Monocyte-derived macrophages prime peripheral T cells to undergo apoptosis by cell-cell contact via ICAM-1/LFA-1-dependent mechanism.
We designed the present study to clarify the mechanism of superantigen-induced apoptosis of human mature T cells and to elucidate the pivotal roles of monocyte-derived macrophages in induction of T cell apoptosis. Exposure of unfractionated human peripheral blood mononuclear cells to SEA, SEB or PHA elicited apoptosis in T cells after 5-day culture. In purified T cell preparations, SEB was unable to induce apoptosis, but was inductive when the purified T cells were cocultured with monocyte-derived macrophages adhering to plastic culture dishes. Placing the T cells in the insert wells which physically separated them from the adhering macrophages resulted in a complete loss of SEB-induced apoptosis. The addition of blocking antibodies against LFA-1, ICAM-1 and CD2 to the cocultures significantly inhibited the SEB-induced T cell apoptosis. We concluded therefore that direct contact of macrophages with T cells is critical in SEB-induced T cell apoptosis, and that adhesion molecules such as LFA-1/ICAM-1 and CD2 may be involved in the mechanism of this effect.
Zen
K
K
National Cardiovascular Center, Osaka, Japan.
Masuda
J
J
Ogata
J
J
D017209:Apoptosis / Q000187:drug effects* / Q000276:immunology*; D018801:CD2 Antigens / Q000494:pharmacology; D002448:Cell Adhesion / Q000276:immunology; D002478:Cells, Cultured; D006801:Humans; D007156:Immunologic Memory / Q000276:immunology*; D018799:Intercellular Adhesion Molecule-1 / Q000494:pharmacology*; D008024:Ligands; D008213:Lymphocyte Activation / Q000276:immunology; D016169:Lymphocyte Function-Associated Antigen-1 / Q000494:pharmacology*; D008264:Macrophages / Q000166:cytology / Q000502:physiology*; D018089:Superantigens / Q000276:immunology / Q000494:pharmacology; D013601:T-Lymphocytes / Q000276:immunology*
D018801:CD2 Antigens; D008024:Ligands; D016169:Lymphocyte Function-Associated Antigen-1; D018089:Superantigens; D018799:Intercellular Adhesion Molecule-1