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The Role of Epitope Specificity in the Human Opsonic Antibody Response to the Staphylococcal Surface Polysaccharide Poly N-Acetyl Glucosamine

  1. Casie Kelly-Quintos1,
  2. Andrea Kropec1,
  3. Stacy Briggs2,a,
  4. Claudia L. Ordonez2,
  5. Donald A. Goldmann3 and
  6. Gerald B. Pier1
  1. 1Channing Laboratory, Department of Medicine, Brigham and Women’s Hospital, and Divisions of
  2. 2Respiratory Diseases and
  3. 3Infectious Diseases, Department of Medicine, Children’s Hospital, Harvard Medical School, Boston, Massachusetts
  1. Reprints or correspondence: Casie Kelly-Quintos, Channing Laboratory, Brigham and Women’s Hospital, Harvard Medical School, 181 Longwood Ave., Boston, MA 02115 (casie_kelly{at}student.hms.harvard.edu)
 
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Abstract

BackgroundThe staphylococcal surface polysaccharide poly N-acetyl glucosamine (PNAG) is a target for killing and protective antibody in animals. We investigated the human antibody response and specificity of binding and opsonic antibodies for different epitopes on PNAG in serum samples from patients with cystic fibrosis (CF) colonized and not colonized with Staphylococcus aureus

MethodsSerum samples from patients with CF colonized and not colonized with S. aureus were used to compare levels and specificities of binding and opsonic antibodies to native PNAG (>95% acetylation) and deacetylated PNAG (dPNAG, ∼15% acetylation)

ResultsColonized patients had higher killing activity mediated by opsonic antibody than did noncolonized patients in a PNAG-specific opsonophagocytic assay (P<.0001) but no difference in average levels of antibody to either PNAG or dPNAG by enzyme-linked immunosorbent assay. Killing activity in serum samples of the colonized patients correlated with the level of IgG specific to dPNAG more than to native PNAG. dPNAG and PNAG shared expression of the epitopes binding opsonic antibody, as evidenced by comparable inhibition of opsonophagocytic killing by both antigens. Affinity-purified antibodies specific to dPNAG were superior in mediating opsonic killing

ConclusionHuman antibodies to PNAG that mediate opsonic killing bind primarily to the nonacetylated epitopes of this antigen, which indicates that these antigenic determinants are the dominant targets of the functional human antibody response to staphylococcal PNAG

Staphylococcus aureus and Staphylococcus epidermidis cause a wide range of hospital infections, and S. aureus is also a serious cause of community-acquired infection [1–4]. There is a great deal of interest in finding vaccine targets for these pathogens. One molecule found in animal studies to be a target of protective antibodies is a β-1-6–linked polymer of N-acetyl glucosamine (PNAG), which has a high level (80%–100%) of the amino groups substituted with acetates [5, 6]. PNAG is also referred to as the capsular polysaccharide adhesin of S. epidermidis and the polysaccharide intercellular adhesin of S. epidermidis and S. aureus. PNAG is synthesized by proteins encoded by the ica locus found in nearly all S. aureus strains and a large number of S. epidermidis clinical isolates [7–10]

Previous studies have shown that rabbits and mice immunized with purified PNAG elicit specific opsonic killing antibodies to both S. aureus and S. epidermidis. In addition, mice immunized with purified PNAG were protected against S. aureus challenge in a kidney infection model [11], and rabbits immunized with PNAG (referred to as capsular polysaccharide adhesin) were protected against catheter-related bacteremia and endocarditis caused by S. epidermidis [12]. However, little is known about the epitope specificity of the opsonic protective antibodies, particularly in the context of the human immune response to PNAG

Because prior work has shown that sputum samples and lung tissues taken from patients with cystic fibrosis (CF) colonized with S. aureuscontain PNAG-elaborating strains [11], it was hypothesized the serum samples from these patients could be investigated to define the epitopic specificity of antibodies to PNAG. Therefore, in the present study, we examined the opsonic killing activity in serum samples from patients with CF of antibodies directed at the deacetylated (backbone) and acetylated epitopes of PNAG, using both whole serum and affinity-purified antibody populations directed at the epitopes in question. We found that human antibodies to the deacetylated epitopes on PNAG were superior at eliciting in vitro opsonic killing, a clear correlate of protective activity of antibodies to gram-positive pathogens

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Materials and Methods

Serum samples from patients with CFSamples were obtained after written, informed consent had been obtained and as approved by the institutional review board of Children’s Hospital, Boston. Clinical and demographic data describing patients included are presented in table 1. Colonized patients were defined as having 3 consecutive positive results for S. aureus from culture of oropharyngeal specimens obtained at least 1 month apart during the year before serum samples were obtained. Patients not colonized with S. aureus were defined as having no positive culture results for this organism during the year before serum samples were obtained, with at least 3 cultures available for review. Serum samples from a total of 31 patients (16 colonized with S. aureus and 15 noncolonized) were collected from subjects with an age range of 1–30 years. Approximately 5 serum samples were collected for each of the following age ranges for both colonized and noncolonized patients: 1–10, 11–20, and 20–30 years

Purification and chemical modification of PNAGThe purification of PNAG was done as described elsewhere [5]. To remove >80% of the N- and O-linked substituents from native PNAG, purified PNAG was dissolved at 0.5 mg/mL in 5 mol/L NaOH and incubated for 18 h at 37°C with stirring. The solution was neutralized to a final pH between 6 and 8, dialyzed against deionized water for 24 h, and freeze dried

Quantitation of PNAG- and deacetylated PNAG (dPNAG)–specific IgG A previously described [5] ELISA protocol was used, with modifications to quantify antibody. These included use of Immulon 4 HBX microtiter plates (Thermo LabSystems) coated with 100 μL of a previously determined optimal binding concentration of each antigen (0.6 μg/mL for native PNAG or 3 μg/mL for dPNAG) dissolved in sensitizing buffer (40 mmol/L phosphate buffer) and incubated overnight at 4°C. Plates were washed 3 times with PBS that contained 0.05% Tween 20 (washing buffer) and were blocked with 200 μL of 5% skim milk dissolved in PBS. Plates were then incubated overnight again at 4°C. Addition of primary and secondary antibodies was as described elsewhere [5]. To quantify PNAG- or dPNAG-specific IgG, a standard curve was generated in the assay, using known concentrations of a protein G–purified human IgG1 monoclonal antibody, F598, which binds to both PNAG and dPNAG [13]. The concentration of purified monoclonal antibody F598 was determined by measurement of the optical density at 280 nm. For the standard curve, we plotted nanograms per milliliter of monoclonal antibody versus the optical density at 405 nm and determined the formula for the best-fit line over the linear portion of the curve, using the least-squares method

Quantification of PNAG- and dPNAG-specific IgM PNAG- and dPNAG-specific IgM were quantified using a protocol similar to the IgG quantification described above, with the following modifications. To generate the standard curve, 2 rows of the microtiter plate were coated with 100 μL of a solution of 0.6 μg of anti–human IgM/mL (Sigma). Human IgM (Sigma) was then added to these wells, and alkaline phosphatase–conjugated anti-human IgM (Sigma; 1:1000 dilution) was used as the secondary antibody for the standard curve and to detect IgM antibodies binding to PNAG- or dPNAG-coated wells

Competition ELISATo determine the specificity of antibodies to acetylated epitopes on native PNAG or backbone epitopes on dPNAG, ELISA plates were sensitized with these antigens and blocked as described above. Serum samples to be analyzed were diluted to a concentration twice that which would result in OD405 readings of ∼1.0. Dilutions of the competing antigens (PNAG or dPNAG) were then mixed with an equal volume of the diluted serum samples, and this mixture was added to the antigen-coated and blocked wells. The remainder of the ELISA continued as described above, although no standard curve was included

Opsonophagocytic assaysThe phagocyte-dependent opsonic killing assay was done as described elsewhere [5]. To make the assay specific to the PNAG molecule, patients’ serum samples diluted 1:10 were adsorbed with 109 cfu/mL for 1 h at 4°C with S. aureus strain MN8Δica [14], which cannot synthesize the PNAG antigen. To determine bacterial killing, 4 components of 100 μL each of diluted, adsorbed serum or purified antibody; 7.5% infant rabbit serum as a complement source; 3×106 peripheral blood leukocytes from various human donors; and 3×105 cfu of S. aureus strain Mn8 [15] as the target organism were mixed for 90 min at 37°C. Surviving bacteria were quantified by dilution and plating. No bacterial killing was observed if any of the 3 immune effector components were left out of the assay

Affinity purification of antibodyAffinity columns were made by covalently attaching purified PNAG or dPNAG to cyanogen bromide–activated Sepharose Fast Flow (Amersham Pharmacia), in accordance with the manufacturer’s instructions. To separate the dPNAG-specific antibodies from the specific antibodies that bind to acetylated PNAG, serum samples were first dialyzed into 20 mmol/L phosphate buffer (pH 7.0), filter sterilized, and loaded onto a column with immobilized dPNAG equilibrated in 20 mmol/L phosphate buffer. After extensive washing to remove unbound antibodies, which were collected for later recovery of native PNAG-specific antibody, the dPNAG-bound antibodies were eluted with 0.1 mol/L glycine buffer (pH 2.6) into tubes that contained a volume of 1.0 mol/L Tris-HCl (pH 9.0) sufficient to immediately neutralize the eluate, after which fractions were pooled and dialyzed overnight into PBS (pH 7.2). The affinity-purified antibodies were concentrated and then analyzed in ELISA and opsonophagocytic assay. The flow-through from the dPNAG column was then added to the PNAG column, and, after extensive washing, antibodies binding to the acetate-dependent determinants on PNAG were eluted in 0.1 mol/L glycine and recovered as described above. ELISA using PNAG and dPNAG as coating antigens was used to monitor the success of the affinity purifications and to test the epitope specificity of the recovered affinity-purified antibodies. Affinity-purified antibodies were then quantified with anti–human IgG (Sigma)–coated ELISA plates, a human IgG standard (Sigma), and secondary antibody, using the ELISA methods described above

Statistical analysisTwo-group comparisons were made by an unpaired t test. Curve fitting and regression analysis used the Prism software package (version 3.0; GraphPad)

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Results

Opsonophagocytic activity of patient serumWe initially tested the ability to mediate PNAG-specific antibody– and complement-dependent opsonophagocytic killing of S. aureus strain Mn8 of 16 serum samples from colonized patients with CF from 15 noncolonized patients. Figure 1 shows that patients colonized with S. aureus had significantly higher PNAG-specific opsonophagocytic killing activity than did noncolonized patients (P<.0001, t test). A broad range of opsonophagocytic killing activity was also evident in the colonized patients’ serum samples. We generally found that the serum samples from the colonized patients with the lowest activity were from the youngest patients (⩽2 years old), which may reflect a shorter exposure period or a reduced ability to mount an antibody response to this bacterial carbohydrate antigen in younger patients with CF

Figure 1
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Figure 1

Opsonophagocytic activity to Staphylococcus aureus in serum samples from patients with cystic fibrosis colonized and not colonized with S. aureus. Serum samples were used at a 1:10 dilution and adsorbed for 1 h with the Δica strain of S. aureus Mn8 to remove non–poly N-acetyl glucosamine–specific antibody before being added into the assay. Opsonophagocytic killing activity of colonized patients was significantly different from that of noncolonized patients (P<.0001, t test)

Epitope specificity of the human antibody response to PNAGduring S. aureus infectionBecause we observed that the noncolonized patients with CF had very low PNAG-specific opsonophagocytic activity against S. aureus and because of the range of killing activity in serum samples from the colonized patients, we examined in more detail at the epitope specificity of the antibody response of these patients to both PNAG and dPNAG. The levels of IgG specific to PNAG and dPNAG, as well as IgM specific to PNAG, were quantified in an ELISA. Table 2 shows that there were no significant differences in either IgM or IgG responses in either group to either the acetate-specific or backbone (deacetylated)–specific epitopes in patients with CF. We also noted a large range of antibody concentrations present in serum samples from both patient groups, as indicated by the SDs. The response to PNAG and dPNAG in both patient populations was overwhelmingly IgG2, with only a small amount (<15%) of an IgG1 response detected (data not shown). Overall, simple quantification of antibody to either PNAG or dPNAG failed to differentiate serum samples with PNAG-specific opsonic killing from serum samples lacking such activity

Figure 2
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Figure 2

A Correlation of poly N-acetyl glucosamine (PNAG)–specific IgG concentration and opsonophagocytic activity of patients with cystic fibrosis (CF) colonized with Staphylococcus aureus (R=0.761, sigmoidal curve fit). B Correlation of deacetylated (d) PNAG–specific IgG concentration and opsonophagocytic activity in colonized patients with CF (R=0.927, sigmoidal curve fit)

Figure 3
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Figure 3

Competition ELISA demonstrating the general pattern of inhibition of binding of antibody to poly N-acetyl glucosamine (PNAG) and deacetylated (d) PNAG antigens, showing the average from 6 serum samples. A Binding of defined concentrations of serum samples resulting in an OD405 of ∼1.0 to a PNAG-coated plate was inhibited using various concentrations of PNAG or dPNAG. Error bars indicate SDs from 6 patient samples, each of which was tested in duplicate. B Binding of defined concentrations of serum samples resulting in an OD405 of ∼1.0 to a dPNAG-coated plate was inhibited using various concentrations of either PNAG or dPNAG. Error bars indicate SDs from 6 patient samples, each of which was tested in duplicate

Figure 4
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Figure 4

Opsonophagocytic killing activity of affinity-purified antibodies to deacetylated poly N-acetyl glucosamine (dPNAG), compared with killing in whole serum from patients with cystic fibrosis (CF) colonized with Staphylococcus aureus. Comparisons for 3 serum samples from patients with CF and antibodies affinity purified using a dPNAG column are shown. Points indicate means of duplicate determinations, and error bars indicate SDs

Figure 5
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Figure 5

Opsonophagocytic killing activity of acetate-specific affinity-purified antibodies (white bars ± SDs) and deacetylated poly N-acetyl glucosamine (dPNAG) (backbone)–specific antibodies (black bars ± SDs). Opsonic killing results obtained using affinity-purified antibodies from 8 different serum samples from patients with cystic fibrosis (CF) colonized with S. aureus are shown. Antibody concentrations in the assay were 5 μg/mL except for sample CF9 dPNAG, which was 1.5 μg/mL. *P<.05

Table 1
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Table 1

Characteristics of patients with cystic fibrosis (CF) colonized or not colonized with Staphylococcus aureus

Table 2
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Table 2

Levels of antibody to poly N-acetyl glucosamine (PNAG) and deacetylated (d) PNAG antigens measured in serum samples from patients with cystic fibrosis colonized or not colonized with Staphylococcus aureus

We next determined whether antibody to a defined glycoform of the PNAG antigen would show a relationship with the level of opsonic killing measured in serum samples from colonized patients. As is seen in figure 2A levels of PNAG-specific IgG correlated modestly with opsonophagocytic killing activity (R = 0.761, sigmoidal regression), and PNAG-specific IgM levels (data not shown) correlated poorly (R = 0.15, linear regression; P=.66). dPNAG-specific IgG levels correlated better with opsonophagocytic activity (R=0.927, sigmoidal regression) (figure 2B). These results indicate that, when opsonic killing activity is present, the antibodies directed to the backbone of PNAG are more functional at phagocyte-dependent killing than are antibodies directed at the acetate-dependent epitopes

To understand better the characteristics of the populations of antibodies that may be present in the serum samples from these patients, competition ELISAs were performed using both the native and deacetylated forms of the antigen as the coating and competing antigens. Figure 3A shows the average of the results from 6 serum samples, which indicate that the native form of PNAG was better able than dPNAG to inhibit the binding of human antibody to an ELISA plate coated with the respective antigen. This result indicates that there are some unshared epitope(s) between PNAG and dPNAG. However, when dPNAG was used to coat an ELISA plate (figure 3B), both PNAG and dPNAG comparably inhibited the binding of antibodies to dPNAG. This result shows that all of the epitopes on dPNAG are also expressed on the native PNAG and that the acetate-specific groups do not block the binding of antibodies directed at the backbone of the PNAG antigen

Opsonic killing activity of affinity-purified antibodies PNAG- and dPNAG-specific antibodies were affinity purified using cyanogen bromide–activated Sepharose to which these 2 antigens had been covalently linked. Because PNAG binds antibodies specific to both the acetylated and nonacetylated epitopes, serum samples were first allowed to bind to the dPNAG column to recover the antibodies specific to these epitopes. The flow-through from the dPNAG column contained antibodies specific to acetylated PNAG that were then affinity purified by use of the PNAG column. ELISAs confirmed that the dPNAG-specific affinity-purified antibodies bound well to both native PNAG and dPNAG, whereas the PNAG-specific antibodies bound only to the acetylated PNAG antigen and not to dPNAG (data not shown). The 2 isolated antibody preparations were then analyzed for killing activity in the opsonophagocytic assay, and all samples were run in the same assay whenever possible, to keep variability to a minimum. Ten serum samples from the colonized patients, including those presented in figure 3, were used to isolate dPNAG- and acetate-specific antibody populations. As expected, for 9 of the 10 serum samples, the opsonophagocytic activity was enriched 30–100-fold when the IgG level was correlated to opsonic killing level. Results in the opsonic killing assay for 3 of these 10 serum samples are shown in figure 4. It is clear from this result that antibodies directed at the backbone of PNAG are major mediators of the opsonophagocytic killing of S. aureus

We were able to successfully purify populations of antibodies specific to either dPNAG or native PNAG from the serum samples from 8 colonized patients. When we compared the opsonic killing activity of the affinity-purified backbone-specific antibodies with that of the affinity-purified acetate-specific antibodies, we found a clear superiority in opsonic killing mediated by the backbone-specific antibodies, compared with the acetate-specific antibodies isolated from the same serum, for 5 of the serum samples (figure 5; samples CF9, CF4, CF13, CF16, and CF17). Interestingly, with 2 of the other 3 serum samples (figure 5; CF3 and CF7), the backbone-specific and acetate-specific antibodies had similar killing activity, and in only 1 sample did dPNAG-specific antibody have lower opsonic killing activity (figure 5; CF11). Overall, we consistently found that antibodies specific to the nonacetylated backbone epitopes of PNAG mediated excellent opsonic killing of S. aureus whereas, in a minority of serum samples, the dPNAG-specific antibodies were equivalent to, but not superior to, acetate-specific antibodies, perhaps because of affinity, fine epitope specificity, or other properties of these less-active dPNAG-specific antibodies

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Discussion

PNAG is a surface polysaccharide produced by pathogenic staphylococci that has previously been shown to be a target for protective immunity in mice and rabbits. In the present study, we have shown, using serum samples from patients with CF colonized or not colonized with S. aureus that one particular group of epitopes on PNAG, which is defined by a lack of acetate substituents on the amino group of the glucosamine monomer, predominantly bound opsonophagocytic antibodies. Although not all opsonic killing antibodies to bacterial pathogens are also protective, essentially all protective antibodies, particularly those protective against gram-positive organisms, have this in vitro property. Thus, it is likely that any PNAG-specific immunity will be dependent on antibodies specific to the epitopes on the dPNAG form of this molecule

Using whole serum from colonized patients, we have shown that opsonophagocytosis correlates better with dPNAG-specific IgG antibodies than with PNAG-specific IgG antibodies. The results of competition ELISAs revealed that PNAG contains both acetate- and backbone-specific epitopes and that dPNAG contains only the backbone-specific epitopes. Because of this observation, it is possible to separate the antibody populations and to examine their opsonic activity individually. For 5 of 8 serum samples, antibodies to dPNAG were superior to those against the native PNAG at mediating opsonic killing. For 2 other serum samples, the killing activity of the antibody was comparable, but, importantly, in these serum samples, both populations of antibodies were not as opsonically active as were the dPNAG-specific antibodies in the other 5 serum samples. In all but 1 instance, PNAG-specific antibodies and antigen were never superior to dPNAG-specific antibody and antigen in terms of mediating or inhibiting opsonic killing activity. Overall, antibodies specific to the backbone of the PNAG molecule will likely be the most useful in preventing and treating staphylococcal disease

PNAG and dPNAG both contain the backbone epitopes, which may explain why IgG specific to PNAG in whole serum from the colonized patients did correlate well with the extent of opsonophagocytic killing. In an additional experiment, we found that both purified PNAG and dPNAG were able to inhibit the opsonophagocytic activity of the serum samples from colonized patients when they were added to the assay (data not shown). This result further demonstrated that the backbone-specific epitopes are targets for opsonophagocytic antibodies and that PNAG and dPNAG share these epitopes

The likely importance of dPNAG in protective immunity has been suggested by the recent identification of the IcaB protein from S. epidermidis—which is produced from the icaB gene within the ica locus—as an extracellular N-deacetylase that removes N-linked acetates from PNAG [16]. In an S. epidermidis icaB mutant, only fully acetylated PNAG is produced, and this form of the antigen cannot be retained on the cell surface. Only partially dPNAG is cell associated. Because it is likely that IcaB in S. aureus functions identically to IcaB in S. epidermidis having a reduced-acetate PNAG antigen retained on the cell surface may potentially explain the superiority of dPNAG-specific antibodies in opsonophagocytic assays

We found that colonized and noncolonized patients had comparable serum levels of antibody to both the native and deacetylated forms of PNAG, which indicates that ELISA measurements did not reflect differences in the functional activities of the antibodies found in colonized patients’ serum samples. Attempts to measure a difference in the affinity of the opsonically active versus inactive antibody to dPNAG—including potassium thiocyanate elution, competition ELISAs using both PNAG and dPNAG as competing antigens, and limiting amounts of coating antigen on the ELISA plate—failed to reveal a difference in antibody affinity to PNAG and dPNAG in serum samples from patients with CF. At the moment, the molecular basis for the difference in opsonic activity between the opsonically active and inactive antibodies has not been identified

The most likely reason that noncolonized patients had quantifiable antibody titers to PNAG is previous exposure to this antigen. Because it is now known that not only pathogenic and commensal staphylococci but also Escherichia coli and potentially many other gram-negative pathogens elaborate PNAG [17], it is clear that there are many possible bacterial sources of exposure to this molecule. Of interest, however, is that noncolonized patients with CF mostly did not develop PNAG-specific opsonic killing activity, which indicates that natural exposure to this antigen is insufficient to generate these potentially protective antibodies

Antibodies to carbohydrate antigens often mediate protective immunity against many bacterial, and even some fungal, pathogens [18–21]. However, the importance of different epitopes formed by various chemical substituents in contributing to protective immunity can be quite variable. For example, O-acetyl substituents on the group C Neisseria meningitidis capsule interfered with induction of protective, bactericidal antibodies when used as a conjugate vaccine in humans [22]. In addition, a deacetylated conjugate vaccine using meningococcal C capsular polysaccharide elicited antibodies that were able to kill strains expressing both O-acetylated and deacetylated serogroup C capsule [23]. In contrast, O-acetyl substituents on the S. aureus capsular polysaccharides seem to have no effect on eliciting opsonic antibody that is effective against strains expressing either high or low levels of acetate on the surface capsular polysaccharide antigen [24]. However, opsonic killing and protective polyclonal human antibodies to the Pseudomonas aeruginosa alginate antigen have been shown to be specific to O-acetyl groups on the mannuronic acid component of the alginate polymer [25], and a human monoclonal antibody to nonacetylated blocks of mannuronic acid has also been shown to mediate opsonic killing and protection in animal models [26]. Thus, even on the same molecule, several different epitopes can bind opsonic protective antibody

In conclusion, we have shown that antibodies elicited in response to the PNAG carbohydrate antigen have different functional properties. Antibodies that recognize epitopes present on both highly and poorly acetylated PNAG appear to be superior in mediating phagocyte-dependent opsonic killing, compared with antibodies that require the presence of high levels of acetate to bind to this antigen. The functional antibodies are produced in response to S. aureus colonization in patients with CF, which indicates that a level of exposure beyond commensal encounters with staphylococci or other organisms elaborating PNAG is needed to produce dPNAG-specific opsonic antibody. In terms of using these data to guide vaccine design, the elicitation of dPNAG-specific antibodies is technically simple and is likely to be a more facile means of producing a protective response. Indeed, preliminary data have shown that the conjugation of dPNAG to a carrier protein elicits high titers of opsonic and protective antibody in animals, whereas the conjugation of highly acetylated PNAG to the same carrier does not elicit protective antibody [27]. The correlation of the functional activity of antibody responses in infected humans and immunized animals to the different epitopes on PNAG substantiates the pursuit of a vaccine based on eliciting high titers of antibodies to the backbone epitopes on PNAG

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Acknowledgments

We thank Tomas Maira-Litran, for purifying and providing the PNAG and dPNAG antigen used in the study, and Katherine Metcalf and Meredith Little, for help in collection of patient data

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Footnotes

  • ↵Presented in part: 103rd general meeting of the American Society for Microbiology, Washington, DC, 18–23 May 2003 (abstract E-117)

    Potential conflicts of interest: G.B.P. is a consultant to and receives research funding from GlaxoSmithKline

    Financial support: National Institutes of Health (grant AI-46706); Cystic Fibrosis Foundation (grant PIER04G0)

  • ↵Present affiliation: Department of Pediatrics, Wake Forest University, Baptist Medical Center, Winston-Salem, North Carolina

  • Received November 29, 2004.
  • Accepted June 17, 2005.
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References

  1. ↵
    1. Wisplinghoff H,
    2. Bischoff T,
    3. Tallent SM,
    4. Seifert H,
    5. Wenzel RP
    . Nosocomial bloodstream infections in US hospitals: analysis of 24,179 cases from a prospective nationwide surveillance study. Clin Infect Dis 2004;39:309-17.
    Abstract/FREE Full Text
  2. ↵
    1. Crossley KB
    1. Boyce J
    . Epidemiology and prevention of nosocomial infections. In: Crossley KB, editor. The staphylococci in human disease. New York: Churchill Livingstone; 1997. p. 309-29.
  3. ↵
    1. Goldmann DA,
    2. Pier GB
    . Pathogenesis of infections related to intravascular catheterization. Clin Microbiol Rev 1993;6:176-92.
    Abstract/FREE Full Text
  4. ↵
    1. Fatkenheuer G,
    2. Preuss M,
    3. Salzberger B,
    4. et al
    . Long-term outcome and quality of care of patients with Staphylococcus aureus bacteremia. Eur J Clin Microbiol Infect Dis 2004;23:157-62.
    CrossRefMedlineWeb of Science
  5. ↵
    1. Maira-Litran T,
    2. Kropec A,
    3. Abeygunawardana C,
    4. et al
    . Immunochemical properties of the staphylococcal poly-N-acetylglucosamine surface polysaccharide. Infect Immun 2002;70:4433-40.
    Abstract/FREE Full Text
  6. ↵
    1. Joyce JG,
    2. Abeygunawardana C,
    3. Xu Q,
    4. et al
    . Isolation, structural characterization, and immunological evaluation of a high-molecular-weight exopolysaccharide from Staphylococcus aureus. Carbohydr Res 2003;338:903-22.
    CrossRefMedlineWeb of Science
  7. ↵
    1. McKenney D,
    2. Hubner J,
    3. Muller E,
    4. Wang Y,
    5. Goldmann DA
    . The ica locus of Staphylococcus epidermidis encodes production of the capsular polysaccharide/adhesin. Infect Immun 1998;66:4711-20.
    Abstract/FREE Full Text
  8. ↵
    1. Muller E,
    2. Hubner J,
    3. Gutierrez N,
    4. Takeda S,
    5. Goldmann DA
    . Isolation and characterization of transposon mutants of Staphylococcus epidermidis deficient in capsular polysaccharide/adhesin and slime. Infect Immun 1993;61:551-8.
    Abstract/FREE Full Text
  9. ↵
    1. Tojo M,
    2. Yamashita N,
    3. Goldmann DA,
    4. Pier GB
    . Isolation and characterization of a capsular polysaccharide adhesin from Staphylococcus epidermidis. J Infect Dis 1988;157:713-22. (erratum: J Infect Dis 1988; 158:268).
    Abstract/FREE Full Text
  10. ↵
    1. Fowler VG Jr.,
    2. Fey PD,
    3. Reller LB,
    4. Chamis AL,
    5. Corey GR
    . The intercellular adhesin locus ica is present in clinical isolates of Staphylococcus aureus from bacteremic patients with infected and uninfected prosthetic joints. Med Microbiol Immunol 2001;189:127-31.
    CrossRefMedline
  11. ↵
    1. McKenney D,
    2. Pouliot KL,
    3. Wang Y,
    4. et al
    . Broadly protective vaccine for Staphylococcus aureus based on an in vivo–expressed antigen. Science 1999;284:1523-7.
    Abstract/FREE Full Text
  12. ↵
    1. Kojima Y,
    2. Tojo M,
    3. Goldmann DA,
    4. Tosteson TD,
    5. Pier GB
    . Antibody to the capsular polysaccharide/adhesin protects rabbits against catheter-related bacteremia due to coagulase-negative staphylococci. J Infect Dis 1990;162:435-41.
    Abstract/FREE Full Text
  13. ↵
    1. Kelly-Quintos C,
    2. Muschenborn S,
    3. Cavacini L,
    4. Posner M,
    5. Goldmann D
    . Proceedings of the 104th general meeting of the American Society for Microbiology. Washington, DC: American Society for Microbiology; 2004. Biological characterization of fully human monoclonal antibodies to staphylococcal surface polysaccharide PNAG [abstract A068].
  14. ↵
    1. Jefferson KK,
    2. Cramton SE,
    3. Gotz F,
    4. Pier GB
    . Identification of a 5-nucleotide sequence that controls expression of the ica locus in Staphylococcus aureus and characterization of the DNA-binding properties of IcaR. Mol Microbiol 2003;48:889-99.
    CrossRefMedlineWeb of Science
  15. ↵
    1. Blomster-Hautamaa DA,
    2. Schlievert PM
    . Preparation of toxic shock syndrome toxin-1. Methods Enzymol 1988;165:37-43.
    MedlineWeb of Science
  16. ↵
    1. Vuong C,
    2. Kocianova S,
    3. Voyich JM,
    4. et al
    . A crucial role for exopolysaccharide modification in bacterial biofilm formation, immune evasion, and virulence. J Biol Chem 2004;279:54881-6.
    Abstract/FREE Full Text
  17. ↵
    1. Wang X,
    2. Preston JF III,
    3. Romeo T
    . The pgaABCD locus of Escherichia coli promotes the synthesis of a polysaccharide adhesin required for biofilm formation. J Bacteriol 2004;186:2724-34.
    Abstract/FREE Full Text
  18. ↵
    1. Shapiro S,
    2. Beenhouwer DO,
    3. Feldmesser M,
    4. et al
    . Immunoglobulin G monoclonal antibodies to Cryptococcus neoformans protect mice deficient in complement component C3. Infect Immun 2002;70:2598-604.
    Abstract/FREE Full Text
  19. ↵
    1. Alonso De Velasco E,
    2. Dekker BA,
    3. Verheul AF,
    4. Feldman RG,
    5. Verhoef J
    . Anti-polysaccharide immunoglobulin isotype levels and opsonic activity of antisera: relationships with protection against Streptococcus pneumoniae infection in mice. J Infect Dis 1995;172:562-5.
    MedlineWeb of Science
  20. ↵
    1. Melegaro A,
    2. Edmunds WJ
    . The 23-valent pneumococcal polysaccharide vaccine. Part I. Efficacy of PPV in the elderly a comparison of meta-analyses. Eur J Epidemiol 2004;19:353-63.
    CrossRefMedlineWeb of Science
  21. ↵
    1. Klugman KP,
    2. Koornhof HJ,
    3. Robbins JB,
    4. Le Cam NN
    . Immunogenicity, efficacy and serological correlate of protection of Salmonella typhi Vi capsular polysaccharide vaccine three years after immunization. Vaccine 1996;14:435-8.
    CrossRefMedline
  22. ↵
    1. Michon F,
    2. Huang CH,
    3. Farley EK,
    4. Hronowski L,
    5. Di J
    . Structure activity studies on group C meningococcal polysaccharide-protein conjugate vaccines: effect of O-acetylation on the nature of the protective epitope. Dev Biol 2000;103:151-60.
  23. ↵
    1. Richmond P,
    2. Borrow R,
    3. Findlow J,
    4. et al
    . Evaluation of de-O-acetylated meningococcal C polysaccharide–tetanus toxoid conjugate vaccine in infancy: reactogenicity, immunogenicity, immunologic priming, and bactericidal activity against O-acetylated and de-O-acetylated serogroup C strains. Infect Immun 2001;69:2378-82.
    Abstract/FREE Full Text
  24. ↵
    1. Fattom AI,
    2. Sarwar J,
    3. Basham L,
    4. Ennifar S,
    5. Naso R
    . Antigenic determinants of Staphylococcus aureus type 5 and type 8 capsular polysaccharide vaccines. Infect Immun 1998;66:4588-92.
    Abstract/FREE Full Text
  25. ↵
    1. Pier GB,
    2. Coleman F,
    3. Grout M,
    4. Franklin M,
    5. Ohman DE
    . Role of alginate O acetylation in resistance of mucoid Pseudomonas aeruginosa to opsonic phagocytosis. Infect Immun 2001;69:1895-901.
    Abstract/FREE Full Text
  26. ↵
    1. Pier GB,
    2. Boyer D,
    3. Preston M,
    4. et al
    . Human monoclonal antibodies to Pseudomonas aeruginosa alginate that protect against infection by both mucoid and nonmucoid strains. J Immunol 2004;173:5671-8.
    Abstract/FREE Full Text
  27. ↵
    1. Maira-Litran T,
    2. Kropec A,
    3. Goldmann DA,
    4. Pier GB
    . Comparative opsonic and protective activities against Staphylococcus aureus of conjugate vaccines containing native or deacetylated staphylococcal poly-N-acetyl-β-(1-6)-glucosamine. Infect Immun 2005;73:6752-62.
    Abstract/FREE Full Text
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  1. J Infect Dis. (2005) 192 (11): 2012-2019. doi: 10.1086/497604
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