Differential expression of the estrogen-regulated proto-oncogenes c-fos, c-jun, and bcl-2 and of the tumor-suppressor p53 gene in the male mouse chronically infected with Taenia crassiceps cysticerci.

Chronic infection with Taenia crassiceps cysticerci produces a 200-fold increase in serum estradiol levels in male mice. The aim of this study was to investigate the expression pattern of c-fos and c-jun, two estradiol-regulated genes, as well as that of p53 and bcl2 in the testes, spleen, and thymus of male mice infected with T. crassiceps cysticerci. In parasitized animals the c-fos mRNA content was significantly increased in all tissues studied, whereas the c-jun mRNA content was increased only in the thymus. The p53 mRNA content was markedly reduced in all tissues of the parasitized animals analyzed, whereas bcl-2 gene expression was abolished in the thymus. On the other hand, thymic cell analysis performed by flow cytometry showed a diminution in the content of CD3+, CD4+, and CD8+ subpopulations in the parasitized mice. Our results suggest that the increase in estradiol levels of the host should change the expression pattern of several genes that participate in apoptosis regulation in the thymus of male mice during chronic infection with T. crassiceps cysticerci.