Immune Sexual Dimorphism During Acute Infection by Toxocara canis: A Novel Approach for an Old Infection

Toxocara canis is a helminth parasite with importance in public and veterinary health. Although different studies have evaluated the immune response, to date there are no studies where it is analyzed from the point of view of sexual dimorphism. At 7 days of infection, female rats had a higher number of larvae in the liver, while male rats had them in the lungs. The percentages of immune cells were evaluated, and in most cases, no significant differences were observed. Regarding the cytokines production, infection can generate a decrease in Th1 such as IL-1β in both sexes and IL-6 only in females. In the case of Th2, IL-4 increases only in infected males and IL-5 increases in males and decreases in females due to the effect of infection. IL-10 also decreases in both sexes as a consequence of the infection and TGF-β only in females. Finally, the infection generates the production of antibody against the parasite, however, their quantity is lower in females. Thus, this study demonstrates that Toxocara canis infection is dimorphic and affects females more than males. This is due to a polarization of the inadequate immune response, which is reflected as a higher parasite load in this sex.