[Enhanced SEC2 mutants and their superantigen activities].
As a superantigen protein, Staphylococcal enterotoxin C2 (SEC2) activates the immune system effectively even in extremely low concentrations, and this property could be applied in adjuvant therapy against tumors and infectious diseases. In order to enhance the superantigen activity of SEC2, the residues at position 102-106 of native SEC2 were substituted for WWH, WWT and WWP by over-lap PCR, and three mutants named ST-1, ST-2 and ST-3 were obtained. Stimulating activity to murine lymphocytes proliferation and inhibiting activity to tumor cell growth of the three mutants were significantly improved compared with the native SEC2. Febrile activities of ST-1 and ST-3 were comparable with the native SEC2, but ST-2 showed markedly increased febrile activity than native SEC2. Moreover, the levels of IL-2, IFN-gamma and TNF-alpha secreted by T cells stimulated with the three mutants were significantly improved, which might be the possible reason for enhanced tumor cell growth inhibition activities. Furthermore, mVbeta8.2 gene transcription levels of murine splenocytes stimulated by the three mutants were dramatically increased compared with native SEC2, suggesting their increased affinities to TCR mVbeta8.2 molecular, which might be the main reason for their enhanced superantigen activities.
Institute of Applied Ecology, University of Chinese Academy of Sciences, Shenyang 110016, Liaoning, China.
Guojun
G
Zhang
Mingkai
M
Xu
Jian
J
Sun
Hongyi
H
Li
Hongli
H
Yang
Huiwen
H
Zhang
Chenggang
C
Zhang
D000818:Animals; D004768:Enterotoxins / Q000235:genetics* / Q000276:immunology*; D005260:Female; D007371:Interferon-gamma / Q000378:metabolism; D007376:Interleukin-2 / Q000378:metabolism; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D050505:Mutant Proteins / Q000235:genetics / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D018089:Superantigens / Q000235:genetics / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D004768:Enterotoxins; D007376:Interleukin-2; D050505:Mutant Proteins; D011948:Receptors, Antigen, T-Cell; D018089:Superantigens; D014409:Tumor Necrosis Factor-alpha; C034959:enterotoxin C, staphylococcal; D007371:Interferon-gamma