Prolonged or permanent survival of skin allografts induced by monoclonal antibodies against lymphocyte subpopulations.

The effect of cytotoxic monoclonal antibodies against T lymphocyte subpopulations on skin allograft survival in mice was compared. Antibodies against cytotoxic lymphocytes (anti-Lyt-2.2) suppressed the allotransplantation reaction more effectively than antibodies against helper/inducer T lymphocytes (monoab anti-Lyt-1.2 and GK1.5). The suppressive effect of anti-Lyt-2.2 antibodies was comparable with that of the antibodies against the whole T lymphocyte population (monoab anti-Thy-1.2). Antibodies anti-Lyt-2.2 led up to a permanent survival (in 40% of animals) of H-2 incompatible skin allografts, when administered for long periods since the day of birth. The effect of the different antibodies, however, depends on the timing of application in relation to skin grafting. The results indicate that prolongation of survival and almost permanent tolerance of skin allografts can be obtained by the specific elimination of T lymphocyte subpopulations by the use of monoab and that Lyt-2 positive T lymphocytes play an important role in rejection allotransplantation reaction.