CUTANEOUS DELAYED-TYPE HYPERSENSITIVITY IN SCID MICE ADOPTIVELY TRANSFERRED WITH LYMPHOCYTES IS B-CELL INDEPENDENT AND H-2 RESTRICTED

Severe combined immunodeficiency (SCID) mice are largely devoid of fun ctional T and B lymphocytes but have normal antigen presenting cell (A PC) capacity. The authors have examined the requirements for cutaneous delayed type hypersensitivity (DTH) in SCID recipients by i.p. transf er of freshly isolated naive mature T cells or non-fractionated spleen cells of H-2 compatible or incompatible origin. Recipient SCID mice w ere epicutaneously sensitized with oxazolone (OXA) within 24 h after c ell transfer. SCID mice injected with as few as 10(5) H-2 compatible B ALB/c (H-2(d)) spleen cells were able to mount DTH ear swelling reacti on upon sensitization and challenge with OXA. Non-fractionated spleen cells from H-2 incompatible B6 or NZW mice were also able to restore D TH capacity in SCID recipients. However, when thymocytes were transfer red, only donor mice expressing H-2(d), but not H-2(b) and H-2(z), hap lotype restored DTH reactivity. Serum levels of IgM and IgM anti-OXA a ntibodies in SCID mice 27 days post-transfer with 10(7) BALB/c spleen cells were similar to that of intact donor mice. In contrast, specific antibodies of IgG isotype were approximately only one-tenth of that f ound in BALB/c controls. The results of this study show that for the d evelopment of cutaneous DTH, in SCID mice transferred with T cells, H- 2 restricted APC-T cell interaction is required, whereas B cells are n ot mandatory. Also, SCID mice transferred with splenocytes show signs of defect immunoglobulin switch function. The authors believe that thi s model of DTH will be useful in delineating the effects of immunomodu latory substances in vivo on distinct host versus donor cell populatio ns.