Differential presentation of group A streptococcal superantigens by HLA class II DQ and DR alleles.
Superantigens have been implicated as pivotal mediators of severe invasive group A streptococcal (GAS) infections, by virtue of their potent immunostimulatory activity. HLA polymorphism has been suggested to influence the susceptibility to severe invasive GAS infection. Here we studied the influence of allelic and isotypic variation of HLA class II molecules on GAS superantigen-induced immune responses using cells derived from patients with bare lymphocyte syndrome, untransfected or transfected with various HLA class II alleles. Significantly higher proliferative responses were detected when streptococcal pyrogenic exotoxin (Spe) A was presented by cells expressing DQA1*0101/DQB1*0302 (DQ3.2), as compared to cells expressing DR1, DR4, or DR5 alleles (p=0.0002-0.01). In contrast to SpeA, SpeC was preferentially presented by DR4 as compared to DQB1*03 (p=0.04). In agreement with the proliferation results, a significantly higher frequency of IL-2-, TNF-alpha-, TNF-beta-, and IFN-gamma-producing cells was detected when SpeA was presented by HLA class II DQB1*03 alleles as compared to DR4 (p=0.0002-0.04). Binding experiments showed a high affinitybinding of SpeA to both class II DR4 and DQB1*0302, and there was no significant difference in SpeA binding affinity between the two alleles. The data confirm the effect of allelic polymorphism in superantigen responses and show that different superantigens are preferentially presented by distinct class II alleles.
Karolinska Institutet, Center for Infectious Medicine - I63, Huddinge University Hospital, Stockholm, Sweden. Anna.Norrby-Teglund@medhs.ki.se
Anna
A
Norrby-Teglund
Gerald T
GT
Nepom
Malak
M
Kotb
D000483:Alleles; D017951:Antigen Presentation; D000942:Antigens, Bacterial / Q000276:immunology*; D001426:Bacterial Proteins; D002478:Cells, Cultured; D005098:Exotoxins / Q000276:immunology*; D005802:Genes, MHC Class II; D006683:HLA-DQ Antigens / Q000235:genetics / Q000276:immunology*; D006684:HLA-DR Antigens / Q000235:genetics / Q000276:immunology*; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis; D008213:Lymphocyte Activation; D008233:Lymphotoxin-alpha / Q000096:biosynthesis; D008565:Membrane Proteins; D016511:Severe Combined Immunodeficiency / Q000473:pathology; D013297:Streptococcus pyogenes / Q000276:immunology*; D018089:Superantigens / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D005098:Exotoxins; D006683:HLA-DQ Antigens; D006684:HLA-DR Antigens; D008233:Lymphotoxin-alpha; D008565:Membrane Proteins; C117980:SpeA protein, Streptococcus pyogenes; D018089:Superantigens; D014409:Tumor Necrosis Factor-alpha; C027951:erythrogenic toxin; D007371:Interferon-gamma