Nematospiroides dubius: two H-2-linked genes influence levels of resistance to infection in mice.

Strains of mice sharing common H-2 haplotypes but different genetic backgrounds, and H-2 congenic strains of mice differing only at H-2 genes were studied to assess the role of H-2 and non-H-2 genes in immunity to challenge infections with the nematode parasite Nematospiroides dubius. Strains of mice sharing the H-2k haplotype were uniformly more susceptible to challenge than strains expressing H-2q alleles, regardless of genetic background. However, in some cases strains of mice sharing the k or q haplotypes differed significantly in levels of resistance. Therefore, non-H-2 genes must influence the response observed. H-2 cogenic strains of mice differed markedly in their ability to resist challenge infections. Mice sharing the C57BL/10 background but expressing k alleles were very susceptible to challenge, while the H-2q, H-2f, and H-2s, haplotypes were associated with resistance. Studies of H-2 congenic recombinant strains of mice suggested that two H-2 genes influence the antiparasite response. One of these genes maps to the left of E alpha and the other to the D-end of the H-2 complex. It is concluded also that the unique configuration of H-2 genes in F1 hybrids contributes to increased resistance to challange.