Oral vaccination with chlGRA4 derived from Toxoplasma gondii prevents deleterious effects associated with congenital toxoplasmosis in mice

SANDER VA; CORIGLIANO, M; ALBARRACÍN, RM; ROMANO, I; CLEMENTE, M

Lima

Simposio; Enfoque multidisciplinario de las enfermedades infecciosas emergentes:de la Biología Molecular al la vigilancia epidemiologica Nacional.; 2014

International Centre for Genetic Engennering and Biotechnology- Universidad Cayetano Heredia

Toxoplasma gondii is the most succesful parasite, which can infect any warm-blooded animal, including humans. In pregnant women, the primary infection with T. gondii may cause serious problems leading to abortion or neonatal malformation. In the present work we determined the protective efficacy of a T. gondii GRA4 antigen obtained by chloroplast transformation (chlGRA4) in tobacco plants to prevent abortion and deleterious effects associated with primary infection during pregnancy. Briefly, female BALB/c mice were orally immunized with tobacco plant extracts expressing chlGRA4 (GRA4 group). Buffer solution was administered to the control group (PBS group). The humoral immune response was evaluated two weeks after the last immunization in mice from the different groups. Mice immunized with chlGRA4 showed GRA4-specific serum antibodies. Immunized mice were paired with Balb/c males and the day of appearance of a coital plug was taken as day 0,5 of pregnancy (P). On day 1,5 of pregnancy, mice from each experimental group were orally challenged with 10 cysts of ME49 T. gondii, excluding 10 animals from PBS group that were not infected (PBS-NI). On day 8,5 of pregnancy, animals were euthanized. Only 30% of PBS infected pregnant mice showed implantation sites (IS) along with diminished serum progesterone levels. In contrast, 60% of GRA4 mice showed IS and serum progesterone levels similar to PBS-NI. Interferon-gamma (IFN-γ) was non detectable in serum from non infected pregnant mice (PBS-NI), while PBS infected females showed high concentration of this cytokine. GRA4 immunized mice showed lower levels of IFN-γ compared to PBS infected mice. IL-5 serum levels were similar between groups. In summary, oral immunization with chlGRA4 elicits an especific immune response and improves reproductive parameters during pregnancy.