TY - JOUR
T1 - Cytoplasmic Membrane-Associated Protein (CAP) Isolated from Streptococcus pyogenes
T2 - As a New Bacterial Superantigen
AU - Sato, Hideki
AU - Itoh, Tetsuro
AU - Rikiishi, Hidemi
AU - Kumagai, Katsuo
N1 - Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 1994
Y1 - 1994
N2 - A protein isolated from the cytoplasmic membranes of Streptococcus pyogenes (cytoplas- mic membrane-associated protein, CAP) stimulated human T cells in vitro to induce their mitogenic response. This CAP-induced T cell proliferation required the presence of nylon-adherent accessory cells (AC) of either autologous or allogeneic origin in the reaction mixtures. In addition, the reaction was inhibited by monoclonal antibodies (mAbs) against major histocompatibility complex (MHC) class II molecules, HLA-DR and -DQ, but not -DP. Human lymphoid cell lines positive for HLA-DR but not those lacking it were also effective as AC for the reaction. A binding test using fluorescein-labeled protein revealed that CAP bound to the adherent monocytes and HLA-DR+ but not to -DR- lymphoid cell lines. The proliferative response of T cells to CAP was, however, not inhibited by the addition of the lysosomotrophic agent NH4Cl to the reaction mixtures. These results suggest that the presentation of CAP by AC to human T cells is mediated through binding of the protein to the MHC class II molecules but without being processed in the AC. The proliferative response of T cells was also found to be inhibited by addition of anti-CD2, -CD3 or -T cell receptor (TcR) mAbs. A major population responding to CAP was CD3+4+8- T cells. CAP also appears to stimulate T cells bearing Vβ8 sequences much more selectively than T cells bearing other Vβs. These results indicate that this streptococcal membrane protein, CAP, may be a new protein belonging to a group of bacterial superantigens.
AB - A protein isolated from the cytoplasmic membranes of Streptococcus pyogenes (cytoplas- mic membrane-associated protein, CAP) stimulated human T cells in vitro to induce their mitogenic response. This CAP-induced T cell proliferation required the presence of nylon-adherent accessory cells (AC) of either autologous or allogeneic origin in the reaction mixtures. In addition, the reaction was inhibited by monoclonal antibodies (mAbs) against major histocompatibility complex (MHC) class II molecules, HLA-DR and -DQ, but not -DP. Human lymphoid cell lines positive for HLA-DR but not those lacking it were also effective as AC for the reaction. A binding test using fluorescein-labeled protein revealed that CAP bound to the adherent monocytes and HLA-DR+ but not to -DR- lymphoid cell lines. The proliferative response of T cells to CAP was, however, not inhibited by the addition of the lysosomotrophic agent NH4Cl to the reaction mixtures. These results suggest that the presentation of CAP by AC to human T cells is mediated through binding of the protein to the MHC class II molecules but without being processed in the AC. The proliferative response of T cells was also found to be inhibited by addition of anti-CD2, -CD3 or -T cell receptor (TcR) mAbs. A major population responding to CAP was CD3+4+8- T cells. CAP also appears to stimulate T cells bearing Vβ8 sequences much more selectively than T cells bearing other Vβs. These results indicate that this streptococcal membrane protein, CAP, may be a new protein belonging to a group of bacterial superantigens.
KW - Cytoplasmic membrane-associated protein (CAP)
KW - Streptococcus
KW - Superantigen
KW - pyogenes
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U2 - 10.1111/j.1348-0421.1994.tb01755.x
DO - 10.1111/j.1348-0421.1994.tb01755.x
M3 - Article
C2 - 8041301
AN - SCOPUS:0028265511
VL - 38
SP - 139
EP - 147
JO - Microbiology and Immunology
JF - Microbiology and Immunology
SN - 0385-5600
IS - 2
ER -