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Protective effect of intranasal immunization with N eospora caninum membrane antigens against murine neosporosis established through the gastrointestinal tract

2013; Wiley; Volume: 141; Issue: 2 Linguagem: Inglês

10.1111/imm.12191

1365-2567

Pedro Ferreirinha, Joana Dias, Alexandra Correia, Begoña Pérez‐Cabezas, Carlos Santos, Luzia Teixeira, Adília Ribeiro, António Rocha, Manuel Vilanova,

Herpesvirus Infections and Treatments

Summary N eospora caninum is an A picomplexa parasite that in the last two decades was acknowledged as the main pathogenic agent responsible for economic losses in the cattle industry. In the present study, the effectiveness of intranasal immunization with N . caninum membrane antigens plus C p G adjuvant was assessed in a murine model of intragastrically established neosporosis. Immunized mice presented a lower parasitic burden in the brain on infection with 5 × 10 7 tachyzoites, showing that significant protection was achieved by this immunization strategy. Intestinal I g A antibodies raised by immunization markedly agglutinated live N . caninum tachyzoites whereas previous opsonization with I g G antibodies purified from immunized mice sera reduced parasite survival within macrophage cells. Although an I g G 1 : I g G 2a ratio < 1 was detected in the immunized mice before and after infection, indicative of a predominant T helper type 1 immune response, no increased production of interferon‐γ was detected in the spleen or mesenteric lymph nodes of the immunized mice. Altogether, these results show that mucosal immunization with N . caninum membrane proteins plus C p G adjuvant protect against intragastrically established neosporosis and indicate that parasite‐specific mucosal and circulating antibodies have a protective role against this parasitic infection.