Genetic control of the murine cell-mediated immune response in vivo. I. H-2-linked responsiveness to the terpolymer L-glutamic acid-60-L-alanine-30-L-tyrosine-10

Mechanisms of genetic control of immune responses. I. Evidence for distinct multi-step helper T-cell pathways in cellular and humoral responses to GAT

We examined multiple genetically regulated humoral and cell-mediated immune (CMI) responses to poly( glu60ala30tyr10 ) (GAT) using a panel of mouse strains. We show that assignment of responder/nonresponder status depends upon the assay method. In addition, two distinct categories of nonresponder mice were found: (1) those which are unresponsive by all parameters tested (H-2q and H-2s haplotypes) and (2) those which are partially nonresponsive [H-2bm12 mutant strain--a low/nonresponder by splenic plaque-forming cell (PFC) and delayed-type hypersensitivity (DTH) responses, but exhibits B6 parental levels of high GAT-specific T-cell proliferation ( Tprlf ) and interleukin-2 production]. The distinction between these two nonresponder types was confirmed by complementation tests in which significant GAT-specific PFC and DTH responses were seen in (H-2q X H-2bm12)F1 hybrids, but not in (H-2q X H-2s)F1 hybrids. Suppressor T cells (Ts) also play a selective role in nonresponsiveness to GAT. Cyclophosphamide treatment of nonresponders (to eliminate Ts activity) as well as immunization with GAT coupled to the immunogenic carrier MBSA result in the development of GAT-specific humoral, but not CMI responses. Our results indicate that the T cell is the cellular site of Ir gene expression and that Tprlf responses do not correlate with functional helper T-cell activity and suggest distinct, multi-step Th/Ts regulatory pathways in the development of humoral and CMI effector functions.

Delayed-type hypersensitivity to ovalbumin in bone marrow chimeric mice

The site of action of the H-2 linked gene regulating the ability of mice to be sensitized to transfer delayed-type hypersensitivity was studied using radiation bone marrow chimeras. Lethally irradiated (non-responder x responder) F1 were reconstituted with bone marrow cells of both parents. Cells of chimeras immunized with limiting doses of ovalbumin responded as did the parental strains. These results suggest that the gene regulating delayed type hypersensitivity is expressed at the level of the delayed-type hypersensitivity effector cels or that restrictions exist on the collaboration of the helper cells for DTH effectors (which differ at several loci including the major histocompatibility complex).