Anti-CD2 antibodies induce T cell unresponsiveness in vivo.
The CD2 receptor functions as an adhesion and signal molecule in T cell recognition. Multimeric binding of CD2 on T cells to its physiologic ligand LFA-3 on cognate partner cells in vitro efficiently augments the antigen-specific T cell signal delivered by the T cell receptor/CD3 complex. The precise contribution of the antigen-nonspecific CD2-LFA-3 interactions to T cell immune responses in vivo, however, has been difficult to assess. Here we analyzed the role of CD2 in the murine immune response using a nondepleting anti-CD2 monoclonal antibody that induces a marked, reversible modulation of CD2 expression on murine T and B cells in situ. This modulation is dose and time dependent, specific for CD2, and does not require the Fc portion of the antibody. Anti-CD2 antibodies [rat IgG1 or F(ab')2] significantly inhibit the CD4+ T cell-mediated response to hen egg lysozyme and the cytotoxic CD8+ T cell response to a syngeneic tumor cell line. In both cases, anti-CD2 antibodies are only effective when administered before or within 24 h after antigen priming. The suppression of the antitumor response corresponds to a sixfold reduction of specific cytotoxic T lymphocyte precursor cells and results in the abrogation of protective antitumor immunity. Anti-CD2 antibodies also affect the humoral immune response to oxazolone: the isotype switch from specific IgM to IgG1 antibodies is delayed, whereas the IgM response is unaltered. In addition, a single antibody injection results in sustained polyclonal unresponsiveness of T cells irrespective of antigen priming and CD2 modulation. These results document that CD2-mediated signals induce a state of T cell unresponsiveness in vivo.
Gückel
B
B
Institute for Immunology and Genetics, German Cancer Research Center, Heidelberg.
Berek
C
C
Lutz
M
M
Altevogt
P
P
Schirrmacher
V
V
Kyewski
B A
BA
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000917:Antibody Formation; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis / Q000276:immunology / Q000502:physiology*; D018801:CD2 Antigens; D015704:CD4 Antigens / Q000032:analysis; D016827:CD8 Antigens / Q000032:analysis; D051379:Mice; D008809:Mice, Inbred C3H; D008811:Mice, Inbred DBA; D009113:Muramidase / Q000276:immunology; D011971:Receptors, Immunologic / Q000032:analysis / Q000276:immunology / Q000502:physiology*; D013601:T-Lymphocytes / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D018801:CD2 Antigens; D015704:CD4 Antigens; D016827:CD8 Antigens; D011971:Receptors, Immunologic; D009113:Muramidase