LIFE-SPAN, T-CELL RESPONSES, AND INCIDENCE OF LYMPHOMAS IN CONGENIC MICE

Survival, T-cell functions, and postmortem histopathology were studied in H-2 congenic strains of mice bearing H-2(b), H-2(k), and H-2(d) ha plotypes. Males lived longer than females in all homozygous and hetero zygous combinations except for H-2(d) homozygotes, which showed no dif ferences between males anti females. Association of heterozygosity wit h longer survival Iras observed only with H-2(b)/H-2(b) and H-2(b)/H-2 (d) mice, Analysis using classification and regression trees (CART) sh owed that both males and females of H-2(b) homozygous and H-2(k)/H-2(b ) mice had the shortest life-span of the strains studied. In histopath ological analyses, lymphomas were noted to be more frequent in females , while hemangiosarcomas and hepatomas were more frequent in males, Ly mphomas appeared earlier than hepatomas or hemangiosarcomas, The incid ence of lymphomas was associated with the H-2 haplotype-e.g., H-2(b) h omozygous mice had more lymphomas than did mice of the H-2(d) haplotyp e. More vigorous T-cell function was maintained with age (27 months) i n H-2(d), H-2(b)/H-2(d), and H-2(d)/H2(k) mice as compared with H-2(b) , H-2(k), and H-2(b)/H-2(k) mice, which shelved a decline of T-cell re sponses with age.