Genetic control of immune responses of inbred mice: Responses against terpolymers poly(glu57lys38ala5) and poly(glu54lys36ala10)

Murine transfer factor. IV. Studies with genetically regulated immune responses

Transfer factor-containing dialysates from mice that were either high or low responders to GAT10, GLA5, or ovalbumin were assayed for their ability to transfer delayed hypersensitivity to murine recipients of either high or low responder phenotype. Dialysates from high responder strains contained transfer factor that would transfer delayed hypersensitivity to both high and low responder recipients. These transfers were not restricted by disparities at the MHC or Igh loci. Identically prepared materials from low responder donors contained little or no transfer factor activity and would not transfer delayed hypersensitivity to either high or low responder recipients. Thus, administration of transfer factor transfers the high responder phenotype to low responder recipients. The data also suggest that production of transfer factor is regulated by Ir genes but that the immunologic activities of transfer factor are not.

Fine specificities of the murine T cell responses to (Glu Lys Ala) terpolymers

The T cell proliferative responses to GLA terpolymers among mice of H-2 a, b, d, k, q, r and s haplotypes are heterogeneous. Following immunization with GLA20, GLA40 and GLA60, mouse T cells reacted well with the three terpolymers. The cross-reactions of the above T cells to GLA5 decreased as the alanine content in the terpolymers (immunogens) increased, whereas the trend of the cross-reactions to GA40 did not change. The RIII strain showed no cross-reaction with GLA5. Only mice of H-2 haplotypes q and s failed to show cross-reactions to GA40. Mice of the H-2q haplotype are genetic non-responders to GA40, whereas those of the H-2s haplotype are responders. Immunization of SJL mice with GA40 mixed with GLA40 led to reduction of the specific T cell response to GA40. This reduction of GA40 specific T cell responses in SJL mice by GLA40 occurred during the early stage of the immune response. The kinetic study showed that it was necessary to inject the GLA40 intraperitoneally at least 7 days before GA40 in order for the reduction to take place. The PETLES and lymph node T cells from DBA/1 mice were found to respond to GLA40 differently, and these cells from SJL mice responded differently to GA40.

Ir gene control of T and B cell responses to determinants in (Glu Lys Ala) terpolymers

All mice responding to the terpolymer GLA40 make GL, GA and GLA specific antibodies irrespective of their response to GL or GA alone. The mice displayed positive T cell proliferative responses against the homologous terpolymer, but no T cell responses were obtained with GL, which is non-immunogenic in mice. T cells from GLA immune mice, which are also responders to GA, such as mice of H-2 haplotypes a, b, d, k and r, could be stimulated by GA. T cells from GLA immune mice of H-2 haplotypes p and q which are non-responders to GA could not be stimulated by GA. On the other hand, T cells from H-2s mice immune to GLA and which are also responders to GA alone could not be stimulated by GA. Thus mice of H-2 haplotypes p, q and s recognize the terpolymer via 'GLA' determinants alone, whereas mice of H-2 haplotypes a, b, d, k and r may recognize both GA and GLA determinants in GLA terpolymer.

Polygenic control of the immune response to F antigen

The ability to produce an autoimmune response to F antigen in mice is under H-2-linked and non-H-2-linked Ir-gene control. There is an absolute requirement for a k allele at H-2K or I-A in order to produce antiF antibodies. Low and high responsiveness is controlled by a non-H-2-linked Ir gene which behaves in a similar fashion to Ir-3, in that as the dose of F-antigen is lowered, low responders behave as high responders and vice versa. This conversion from low to high responders and vice versa. This conversion from low to high responsiveness also occurs within a month after ATX.-Most F1 hybrids derived from (responder X nonresponder) parents bearing identical F-types behave as dominant nonresponders. As a result of ATX, such F1 mice convert to high responders . This conversion occurs if the animals are not immunized before day 90. If they receive F antigen prior to that time, they remain nonresponders for 7-9 months. One F1 combination showed--AKD2--behaves as an dominant higher responder. Genetic analysis showed that the presence of a K allele at H-2K or I-A, a non-H-2-linked Ir gene inherited from the AKR mice determined dominant responsiveness. No manipulation of the immune response or combination of genes converted nonresponders lacking a k allele into responders. Such complex genetic control suggests regulation by a number of independently segregating loci whose function it is to limit the autoimmune response to F antigen.

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 immune response to ferritin in mice

The immune response to the antigen horse spleen ferritin was tested in sixteen inbred strains of mice. Using a fixed antigen percentage bound isotope technique, it was found that the quantity of antibody produced was related to the genetic status of the responding animal. A continuous distribution of responses was obtained, which were found to be linked to H-2 loci and the 2 non-H-2 loci 'Tla' and 'Theta' and these responses are detectable following primary immunization. It is suggested that the continuous distribution of quantitative antibody responses to ferritin, is compatible either with a large number of IR-genes or with a cross tolerance hypothesis requiring no IR-genes at all.