Peritoneal exudate T lymphocytes with specificity to sheep red blood cells. IV. Fc receptors on specific peritoneal exudate lymphocytes and their role in delayed-type hypersensitivity reactions.

In mice, delayed-type hypersensitivity (DTH) to sheep red blood cells (SRBC) is mediated by T cells. Peritoneal exudate T cells (PETLs) from mice optimally sensitized for DTH to SRBC form rosettes when interacted with sensitized sheep red blood cells (EA). The binding of EA to PETLs is mediated by a receptor specific for the Fc portion of the antibody (FcR). Biological activity (mediation of DTH) depends on the unreacted state of PETLs and is lost when the latter are either rosetted with EA or reacted with aggregated IgG. Transfer of EA or aggregated IgG-treated PETLs from mice with DTH to SRBC does not lead to adoptive sensitization of recipients. It is suggested that FcR found on the membrane of T cells mediating DTH play a role in the regulation of the cellular immune response to SRBC.