Role of class II histocompatibility antigens in Staphylococcus aureus protein A-lnduced activation of human T lymphocytes (original) (raw)
Scandinavian Journal of Immunology, 1997
The importance of the MHC class II region for the development of septic arthritis was studied in a murine model of haematogenously induced Staphylococcus aureus arthritis. In the first experiment MHC class II deficient mice (Ab ¹=¹ ) and their heterozygous (Ab þ=¹ ) littermates were intravenously inoculated with a single dose of toxic shock syndrome toxin-1 producing S. aureus LS-1 strain. The results demonstrate that the expression of class II MHC molecules increases the prevalence and severity of arthritis. To analyse the impact of MHC class II haplotypes on the disease onset and progression the authors used congenic C3H.NB, C3H.Q and C3H/HeJ mice in the second set of experiments. The results show that C3H/HeJ mice developed the highest frequency and the most severe course of arthritis compared with C3H.NB and C3H.Q animals. Immunohistochemical analysis of arthritic joints revealed equal number of macrophages, CD4 þ and CD8 þ lymphocytes in the inflamed synovia in all the congenic mice. In contrast, the number of MHC class II expressing cells was higher in the arthritic joints of C3H/HeJ mice compared with the congenic strains (P < 0.001). Furthermore, serum levels of proarthrtitogenic cytokines, such as tumour necrosis factor and interleukin-6 were higher in C3H/HeJ group. This study indicates that MHC class II expression is necessary for the development of S. aureus arthritis in mice and that different MHC class II haplotypes confer varying susceptibility for development of joint inflammation induced by staphylococci.
Human antibody responses against non-covalently cell wall-bound Staphylococcus aureus proteins
Scientific reports, 2018
Human antibody responses to pathogens, like Staphylococcus aureus, are important indicators for in vivo expression and immunogenicity of particular bacterial components. Accordingly, comparing the antibody responses to S. aureus components may serve to predict their potential applicability as antigens for vaccination. The present study was aimed at assessing immunoglobulin G (IgG) responses elicited by non-covalently cell surface-bound proteins of S. aureus, which thus far received relatively little attention. To this end, we applied plasma samples from patients with the genetic blistering disease epidermolysis bullosa (EB) and healthy S. aureus carriers. Of note, wounds of EB patients are highly colonized with S. aureus and accordingly these patients are more seriously exposed to staphylococcal antigens than healthy individuals. Ten non-covalently cell surface-bound proteins of S. aureus, namely Atl, Eap, Efb, EMP, IsaA, LukG, LukH, SA0710, Sle1 and SsaA2, were selected by bioinfor...
Scientific Reports
The immunodominant staphylococcal antigen A (IsaA) is a potential target for active or passive immunization against the important human pathogen Staphylococcus aureus. Consistent with this view, monoclonal antibodies against IsaA were previously shown to be protective against S. aureus infections in mouse models. Further, patients with the genetic blistering disease epidermolysis bullosa (EB) displayed high IsaA-specific IgG levels that could potentially be protective. Yet, mice actively immunized with IsaA were not protected against S. aureus infection. The present study was aimed at explaining these differences in IsaA-specific immune responses. By epitope mapping, we show that the protective human monoclonal antibody (humAb) 1D9 recognizes a conserved 62-residue N-terminal domain of IsaA. The same region of IsaA is recognized by IgGs in EB patient sera. Further, we show by immunofluorescence microscopy that this N-terminal IsaA domain is exposed on the S. aureus cell surface. In contrast to the humAb 1D9 and IgGs from EB patients, the non-protective IgGs from mice immunized with IsaA were shown to predominantly bind the C-terminal domain of IsaA. Altogether, these observations focus attention on the N-terminal region of IsaA as a potential target for future immunization against S. aureus. Staphylococcus aureus can cause a wide variety of diseases and has a strong tendency of developing resistance against multiple antibiotics 1. Methicillin-Resistant S. aureus (MRSA)-associated infections are becoming increasingly harder to treat. Therefore, a renewed focus on the development of alternative means of treatment has arisen. Whereas many infectious diseases are nowadays controlled through vaccination, S. aureus immunity has proven hard to achieve with vaccines 2-5. As an alternative to the active immunization against S. aureus with vaccines, passive immunization with monoclonal antibodies specifically targeting S. aureus is currently explored 6-11. Invariantly expressed cell surface-exposed proteins are attractive potential targets for immunization, due to their high accessibility to the human immune system 12. This focused attention on the immunodominant S. aureus antigen A (IsaA). The IsaA protein was first described in the year 2000 as an antigen recognized by IgGs from patients with sepsis caused by MRSA 13. Subsequent, proteomic analyses of the S. aureus exoproteome revealed that the IsaA protein was invariantly produced by all investigated isolates of this pathogen 14, 15. More specifically, IsaA is a non-covalently cell wall attached protein that is both exposed to the cell surface and secreted 13, 16, 17. The IsaA protein has a putative soluble lytic transglycosylase domain at the C-terminus, indicating a role in peptidoglycan turnover and cell wall hydrolysis 17, 18. Interestingly, this C-terminal active site domain is exposed to the staphylococcal cell surface while the precise localization of the N-terminal domain was so far not known 12, 18 .
Use of staphylococcal protein A as an immunological reagent
Journal of Immunological Methods, 1978
This brief review summarises the major uses of staphylococcal protein A in immunology. Protein A is covalently linked to the cell wall of most strains of Staphylococcus aureus, and binds immunoglobulin molecules with high affinity. The principal molecule bound is IgG, although in many cases binding is restricted to certain IgG subclasses. Some IgM and IgA binds in certain species. This property allows rapid, simple and economical methods for the purification and analysis of immunoglobulins, and the fractionation of subclasses which are difficult to separate by other means. Fractionation on protein A affinity columns is a simple and efficient way of separating immunoglobulin F(ab) and F(ab')2 from Fc fragments. Intact staphylococci are useful as a solid phase adsorbent for isolating antigen--antibody complexes, membrane antigens and receptors, and to replace 'second antibody' in radioimmunoassay. Finally, protein A has proven useful for the study of antigens and receptors on the surface of intact cells, and for the detection of antibody-secreting cells. Thus, the use of protein A is now the method of choice for many preparative and analytical purposes in immunology.
Clinical & Experimental Immunology, 2008
Two cationic proteins, a neutral phosphatase (NP-tase) and a 70-kD protein (p70) were isolated from Staphylococcus aureus by ion exchange chromatography. We compared their properties to those of the well established B cell mitogen of whole, fixed Staph. aureus strain Cowan I cells (SAC). Both purified proteins were able to induce immunoglobulin synthesis in PBMC cultures of healthy donors. NP-tase and p70 also induced immunoglobulin synthesis of PBMC from those patients with CVID who were also responsive to SAC plus IL-2 stimulation. Immunoglobulin synthesis in response to NP-tase and to p70 was time-and dose-dependent and could be inhibited by addition of specific antibodies against the proteins. In contrast to SAC, no addition of exogenous IL-2 was necessary to obtain maximal immunoglobulin synthesis induced by NP-tase or p70. However, neither protein was able to induce immunoglobulin synthesis in B cell-enriched cultures. High amounts of IL-2 were found in supernatants of PBMC from healthy donors following stimulation with low concentrations of NP-tase or p70, and this was associated with vigorous lymphocyte proliferation. Both proteins behave like typical antigens, and not like lectins or superantigens, since an NP-tase-stimulated T cell line showed an antigen-specific, MHCrestricted secondary response. In addition, no preferential T cell receptor V/3 chain usage was found with eight V,3-specific MoAb. It is likely that the two proteins induce antigen-specific T cell activation, which is then followed by polyclonal activation of B cells via CD40 receptors and cytokine release
Induction of specific clonal anergy in human T lymphocytes by Staphylococcus aureus enterotoxins
Proceedings of the National Academy of Sciences of the United States of America, 1990
The exotoxins produced by certain strains of Staphylococcus aureus are able to stimulate powerful polyclonal proliferative responses and to induce nonresponsiveness by clonal deletion of T lymphocytes expressing the appropriate T-cell antigen receptor VP gene products. This paper examines the ability of S. aureus enterotoxins to modulate the respon
PLOS ONE, 2015
Proteomic studies with different Staphylococcus aureus isolates have shown that the cell surface-exposed and secreted proteins IsaA, LytM, Nuc, the propeptide of Atl (pro-Atl) and four phenol-soluble modulins α (PSMα) are invariantly produced by this pathogen. Therefore the present study was aimed at investigating whether these proteins can be used for active immunization against S. aureus infection in mouse models of bacteremia and skin infection. To this end, recombinant His-tagged fusions of IsaA, LytM, Nuc and pro-Atl were isolated from Lactococcus lactis or Escherichia coli, while the PSMα1-4 peptides were chemically synthesized. Importantly, patients colonized by S. aureus showed significant immunoglobulin G (IgG) responses against all eight antigens. BALB/cBYJ mice were immunized subcutaneously with a mixture of the antigens at day one (5 μg each), and boosted twice (25 μg of each antigen) with 28 days interval. This resulted in high IgG responses against all antigens although the response against pro-Atl was around one log lower compared to the other antigens. Compared to placebo-immunized mice, immunization with the octa-valent antigen mixture did not reduce the S. aureus isolate P load in blood, lungs, spleen, liver, and kidneys in a bacteremia model in which the animals were challenged for 14 days with a primary load of 3 × 10 5 CFU. Discomfort scores and animal survival rates over 14 days did not differ between immunized mice and placebo-immunized mice upon bacteremia with S. aureus USA300 (6 × 10 5 CFU). In addition, this immunization did not reduce the S. aureus isolate P load in mice with skin infection. These results show that the target antigens are immunogenic in both humans and mice, but in the used animal models do not result in protection against S. aureus infection. PSMα1-4, or with placebo. Animals were infected by intradermal inoculation of S. aureus isolate P (3 × 10 7 CFU), and were monitored for 7 days. (A) Animal body weight over time after S. aureus skin infection was not affected by vaccination (P > 0.05; Quade's rank analysis of covariance). (B) Lesion size was significantly reduced by vaccination, as indicated by the asterisk (P = 0.005; Quade's rank analysis of covariance). (C) S. aureus load in the skin lesion at day 7 was not reduced by vaccination (P > 0.05; Mann-Whitney U test).