Genetic control of two independently segregating loci in mice to the sequential polypeptide (Tyr-Ala-Glu-Gly)n

Murine Gc globulin binds to a synthetic sequential polypeptide that is a murine B lymphocyte mitogen

A non-immunoglobulin component in mouse serum was found to compete with antibody for the binding of a polyanionic antigen, poly (Tyr-Glu-Ala-Gly). The percent of the polymer (44 ng/ml) bound at physiological pH by the serum component in normal mouse serum was low (18%), but was much higher at pH 6.0 (85%). As a result, the binding of the polyanionic peptide antigen by antibody in immune serum was considerably lower at pH 6.0 than it was at physiological pH. These results should be taken into account when dealing with similar antigens that have been frequently studied in immunology, such as poly (Glu60 Ala40) and poly (Glu60 Ala30 Tyr10). The non-immunoglobulin serum component has been identified as Gc globulin, a vitamin D-binding protein that has been shown to be present on the surface of B lymphocytes. This binding might be responsible for the murine B cell mitogenicity of poly (Tyr-Glu-Ala-Gly) that has been previously reported.

Genetic control of the immune response to haemoglobin. II. Studies using purified alpha-chain and beta-chain as immunogens

Mice of independent haplotypes and several recombinant inbred strains were immunized with highly purified preparations of either the alpha-chain or beta-chain subunit of human adult haemoglobin. Cells from the sensitized lymph nodes were challenged in vitro with the appropriate subunit (or in some cases both chains) and cell proliferation assessed by 3H-thymidine incorporation. Mice of the H-2b and H-2d haplotypes were high responders to alpha-chain while mice of the H-2f, H-2j, H-2k, H-2r, H-2s, H-2u, and H-2v haplotype were low responders. the low responsivenesss of B10.A(4R) and B 10.MBR and high responsiveness of B10 indicated that the Ir gene(s) determining responsiveness to the alpha-chain subunit resides in the I-A subregion of the mouse major histocompatibility complex. Mice of the H-2d, H-2f, and H-2s haplotypes were high responders and H-2b, H-2j, H-2a, and H-2u haplotype mice were low responders to beta-chain. H-2k, H-2p, H-2r, and H-2v haplotype mice were intermediate responders to beta-chain. The low responsiveness of B10.S(8R) and B10.TL and the high responsivenes of B10.S(9R) mapped the Ir gene(s) to beta-chain to the I-A subregion. Data collected from challenging high responder cells with both subunit indicated that alpha-chain and beta-chain do not crossreact. These results are discussed in reference to earlier observations suggesting that the low responsiveness of some strains of mice to priming and challenging using the intact haemoglobin molecule might be due to a negative regulatory influence mediated by one of the subunits. In the absence of this influence these mice would respond normally.

Genetic regulation of antibody response to sheep red blood cells: linkage to H-2 complex

The analysis of anti-sheep red blood cell (SRBC) antibody production in the congenic resistant (CR) mouse strains A/J and A.BY, B10 and B10.A showed that the level of IgG antibodies after immunization with SRBC is controlled by a gene(s) localized in the H-2 complex. The use of h2,h4, and i5H-2 recombinant haplotypes allowed us to map this gene into a region proximally defined by subregion I-J and distally by region H-2G. The IgG antibody level is simultaneously under the influence of non-H-2 genes, of which those of the A/J strain origin determine the high IgG level and those of the B10 strain origin determine the low IgG level. Weights of spleens of the A/J and B10 mice before and after primary and secondary immunization with SRBC were compared. Before immunization, spleens of the A/J mice were approximately 10% lighter than those of the B10 mice (0.08 g vs 0.09 g). After the first immunization the spleen weights equalized (0=0.12 g). Four days after the second immunization the weight of the spleens of A/J mice increased by 312% (relative to the nonimmune state) while that of the B10 mice increased by only 74%. These findings indicate that the cell antigen-specific proliferation in spleens of A/J mice was considerably higher than that in spleens of B10 mice.

Immune responses of inbred guinea pigs and mice to helical sequential polymers of amino acids

The immune responses against the sequential polypeptides; (T-G-A-Gly)n, (T-A-G-Gly)n, (Phe-G-A-Gly)n and (Phe-A-G-Gly)n were studied in inbred guinea pigs and mice. Strain 13 guinea pigs responded to (Phe-G-A-Gly)n and (T-G-A-Gly)n whereas strain 2 guinea pigs responded to (T-A-G-GLY)n and (Phe-A-G-Gly)n. These responses which are linked to MHC, are only against the helical form of the polymers which have conformational determinants. Significant cross reactions at the humoral and T cell levels (PELS) are exhibited with the following reciprocal combinations: (Phe-G-A-Gly)n and (T-G-A-Gly)n; (T-A-G-Gly)n and (Phe-A-G-Gly)n. With mice, the polymers were shown to be T dependent with the following response patterns: mice of H-2b haplotype respond against (T-G-A-Gly)n; those of H-2b, f and r haplotypes respond against (T-A-G-Gly)n. There are no responders against (Phe-G-A-Gly)n and only mice of H-2f respond against (Phe-A-G-Gly)n. "Nonresponders" respond against the MBSA aggregates of all of these polymers. The Ir gene(s) controlling these T cell dependent H-linked responses mapped to the IA subregion. Antibody responses against (T-G-A-Gly) and (T-A-G-Gly) were quite variable, and were most marked in, F1 mice of (responder and nonresponder) and in backcross populations of (F1 x R) and (F1 x NR). However, the T cell proliferative responses performed with nylon wool purified T cells gave clear cut and predictable distinctions between "responders" and nonresponders and linkage with responding haplotype. Hypotheses advanced to explain these findings relate to the poor immunogenicity (antibody) of these polymers, which have a restricted number of repeating determinants, the B cell mitogenic properties of these polymers and the possible involvement of suppressor cells. The specificities of the humoral responses, i.e. cross reactions, were similar to those found in guinea pigs. However, in contrast to the guinea pig studies cross stimulation with structurally related polymers occurred only in those situations where the immunizing and "crossreacting" polymers were both immunogenic in mice of the same haplotype, i.e., (T-A-G-Gly)n and (Phe-A-G-Gly)n in mice of H-2f haplotypes.