GENETIC-CONTROL OF SUSCEPTIBILITY TO TAENIA-CRASSICEPS CYSTICERCOSIS

We previously reported that genes within the major histocompatibility complex influence the intensity of Taenia crassiceps murine cysticerco sis. This genetic control, readily apparent in mice of BALE background , was further studied in H-2 congenic and recombinant B10 mice as well as in BALB/c substrains differing in expression of Qa-2 antigens. Sim ilarly low parasite numbers were found in all B10-derived strains infe cted, regardless of H-2 haplotype, indicating that the effect of H-2 g enes in controlling susceptibility is overridden in mice of B10 backgr ound. BALB/c substrains differed significantly in susceptibility. BALB /cAnN was highly susceptible, whereas BALB/cJ, in contrast, was highly resistant and BALB/cByJ showed intermediate susceptibility. Susceptib ility or resistance in BALB/c substrains may be associated to differen ces known to distinguish them, such as serum testosterone levels and Q a-2 protein expression. In bidirectional F1 hybrids of C57BL/6J and BA LB/cAnN resistance to cysticercosis was inherited as a dominant autoso mal trait. In F1 hybrids of BALB/cJ with BALB/cAnN, BALB/cByJ and BALB .K resistance was also inherited as a dominant trait. However, in (BAL B/cAnN x BALB/cByJ)F1 and (BALB/cAnN x BALB.K)F1 hybrids, dominant sus ceptibility to cysticercosis was observed.