Do interleukin-6 and macrophage-migration inhibitory factor play a role during sex-associated susceptibility in murine cysticercosis?

In murine Taenia crassiceps cysticercosis, females sustain larger intensities of infection than males. However, during chronic infection, this difference disappears and males show a feminization process. To further study the role of two cytokines, interleukin-6 (IL-6) and macrophage-migration inhibitory factor (MIF), known to be involved in immunoendocrinological processes during sex-associated susceptibility in cysticercosis, IL-6 and MIF gene knockout (KO) mice were infected, and the number of parasites and serum sex-steroid levels were measured. Results show that IL-6 and MIF KO mice of both genders infected with T. crassiceps cysticerci harbor similar numbers of parasites, with no change in sex-hormone levels. However, in wild-type strains, females have twice as many parasites as males. At the same time, there is a decrease of 80% in testosterone and dihydrotestosterone serum levels, and a 100-fold increase in the levels of estradiol in infected male mice. These results suggest a role for both IL-6 and MIF genes in sex-associated susceptibility in murine T. crassiceps cysticercosis.