Selective reconstitution of T lymphocyte subsets in scid mice.

The 'empty' splenic T-cell compartment of young scid mice was partially and selectively reconstituted by low numbers of adoptively transferred congenic (C.B-17, BALB/c) or semi-allogeneic (dm2), but not completely allogeneic (C57BL/6) CD4+ T cells from adult donor mice. Under the same experimental conditions, the CD8+ T-cell compartment of young scid mice could only be reconstituted in scid mice continuously substituted with IL-2. CD4+ T cells engrafted in the spleen of H-2d scid recipients displayed specific, anti-Ad-associated proliferative reactivity. (Semi)allogeneic CD8+ T cells engrafted in spleens of scid recipients showed no anti-host H-2 class I-associated cytotoxic reactivity, i.e., this T-cell compartment was specifically tolerized against host (allo)antigens. Reconstitution of lymph nodes was not observed following transplantation of purified CD4+ or CD8+ T cells. Antigen-specific, cellular immune responses could not be induced in scid mice selectively reconstituted with either CD4+ T cells or CD8+ T cells. Partial reconstitution of the CD4+ T-cell compartment was always associated with the appearance of scid-derived, 'endogenous' IgM-producing B cells. Serum antibodies of scid mice with this T cell-induced B-cell leakiness stained an immature subset of congenic thymocytes.