Cellular and biochemical responses of human T lymphocytes stimulated with streptococcal M proteins

• Published in: The Journal of immunology (1950) Vol. 142; no. 3; pp. 966 - 970
• Main Authors: Kotb, M, Courtney, HS, Dale, JB, Beachey, EH
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Am Assoc Immnol 01-02-1989; American Association of Immunologists
• Subjects: Analysis of the immune response. Humoral and cellular immunity; Antigens, Bacterial; Bacterial Outer Membrane Proteins; Bacterial Proteins - pharmacology; Biological and medical sciences; Carrier Proteins; Cross Reactions; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Humans; Immunobiology; Lymphocyte Activation - drug effects; Myocardium - immunology; Organs and cells involved in the immune response; Phosphorylation; Serine - metabolism; Streptococcus; T-Lymphocytes - classification; T-Lymphocytes - immunology; T-Lymphocytes - metabolism; T-Lymphocytes, Cytotoxic - drug effects; T-Lymphocytes, Regulatory - drug effects; Tyrosine - metabolism; Human; Modification; Phosphorylation; Cell function; Radiolabelling; Gel electrophoresis; Cytotoxicity test; Helper cell; Cytotoxicity; Biochemistry; Cell differentiation; Cell subpopulation; Cell surface; Proteins; Streptococcaceae; Streptococcus; T-Lymphocyte; Bacteria; Micrococcales; Suppressive cell
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.142.3.966

Purified group A streptococcal M proteins, pep M5 and pep M6, bearing heart cross-reactive epitopes were compared with pep M24, which lacks such epitopes, in their ability to induce functional differentiation of human T lymphocytes. Lymphocytes activated by pep M5 and pep M6 demonstrated cytotoxic activity against cultured heart cells, whereas pep M24-activated cells differentiated into suppressor T cells, which specifically blocked cytotoxic T lymphocytes against cultured human myocardial cells and not NK cell activity against K562 cells. Pep M5 and not pep M24 induced an increase in the number of CD4, 4B4, helper/inducer T cells. In addition, these M proteins appear to induce different biochemical changes in T lymphocytes. Both pep M5 and pep M24 induced the phosphorylation of a 35-kDa cytoplasmic protein; however, only pep M5 induced the phosphorylation of a 28-kDa membrane protein, primarily in CD4 T cells. These data indicate that the virulent M protein Ag of group A streptococci may exert their effect on the human immune system via different mechanisms. Determining these mechanisms and the biochemical pathways involved in T cell differentiation triggered by these Ag may be important in understanding the pathogenesis of post-streptococcal diseases.