Genetic control of the immune response to a thymus independent synthetic polypeptide

Codominant inheritance in immunogenetic (IR-gene) systems

Immunogenetic (IR-gene) systems consist of animals showing different quantitative antibody responses when immunized with similar doses of a given antigen. Strains of animals giving high and low antibody titres are described as high and low responders, respectively. The degree of dominance in F1 hybrid strains, obtained from a cross between high and low responder parents, can readily be calculated using the dominance index formula, which takes the value of +1 for complete dominance, -1 for complete recessivity and the value of zero for no dominance. In reviewing 1527 F1 animals, obtained from ninety-one immunogenetic systems, the degree of diminance (d) was found to be: +0-0076 +/- 0-1053 (mean +/- s.e.), which is close to a value of zero and this is consistent with codominant inheritance. It is suggested that in immunogenetic systems, both alleles are expressed as codominant genes.

Genetic control of the antibody response to type III pneumococcal polysaccharide in mice. III. Analysis of genes governing the expression of regulatory T cell activity

Recombinant-inbred strains of mice, as well as the progenitor strains from which they were derived, were evaluated with respect to the capacity of B cells to respond to an optimally immunogenic dose of Type III pneumococcal polysaccharide (SSS-III) and the amount of suppressor and amplifier T cell activity present. None of these functional activities was found to be linked to genes within the major histocompatibility (H-2) or the IgCH allotype complex, and several autosomal genes appeared to govern the expression of each of these characteristics.

Analysis of the role of different cell types in the genetic regulation of antibody production to the thymus-independent synthetic polypeptide poly (DTyr, DGlu)-poly (DPro)--poly (DLys)

The immune response potential of mice to the thymus-independent synthetic polypeptide poly (DTyr, DGlu)-poly(DPro)--poly(DLys)[D(T,G)-Pro--L] is genetically regulated. The defect in the ability of low responder mice to mount an immune response to this antigen appears to be expressed in their B cell population since the presence of thymocytes, or addition of "educated T cells" or supernatant of T cells after stimulation with the antigen neither enhanced, nor suppressed the level of antibodies produced in both low and high responder mice. Low responsiveness could not be enhanced either by stimulation of macrophages or by injection of poly(A) - poly(U) in contrast to the significant effect of these agents on low responses to the thymus-dependent poly(LTyr, LGlu)-poly(LPro)--poly(LLys) [L(T,G)-Pro--L]. These results suggest that macrophages do not participate in the limiting step, or are not involved at all, in antibody production towards the thymus-independent polypeptide. The antibodies produced in response to D(T,G)-Pro--L were found to be mainly of the 7 S class. T cells are not required for the production of mercaptoethanol resistant antibodies to this immunogen since they were found in intact mice as well as in T cell depleted animals.