THE IMMUNE ENHANCEMENT OF A NEOSPORA CANINUM VACCINE BY A NOVEL SOY LECITHIN/â -GLUCANS BASED ADJUVANT

MANSILLA, F; MOORE DP; FRANCO MAHECHA O; LAVORIA M; GIRALDEZ A; IGLESIAS M; WILDA M; CAPOZZO A

Lima

Congreso; X Congress of the Latin Asociation of Immunology; 2012

Efficient, cost-effective and safe Th1-immunity-inducing vaccine formulations are paramount for achieving protection against Neospora caninum. In this study, a new adjuvant ( Providean-AVEC ® ) was developed and tested in a N. caninum vaccine. Potency was assessed by evaluating cerebral infection of BALB/c mice. Soluble N. caninum tachyzoite native protein extract (sNcAg), the insoluble extract (iNcAg) and killed tachyzoites were evaluated as vaccine-antigen candidates based on their capacity to activate dendritic cells (DC) invitro. sNcAg was the only preparation that activated the production of pro-inflammatory cytokines on DC. Vaccines were formulated with two different antigen payload, 4 and 0.4 µg of sNcAg, adjuvanted with Providean-AVEC ®, ISCOM-Matrix or aluminum hydroxide (Alum). Mice were immunized subcutaneously at 2 weeks interval (2 doses). While mice vaccinated with4 µg of sNcAg + Providean-AVEC ® developed specific   antibodies shortly after the first dose, the rest of the high antigen payload formulations only induced seroconversion after the booster. Mice immunized with the high payload ISCOM vaccine (4 µg sNcAg) or with either low or high payload Providean -AVEC ® formulations (0.4 µ g and 4 µg sNcAg, respectively) elicited higher IgG2a than IgG1 serum levels, and IFN-gamma anamnesticresponses with a Th1-cytokine biased profile.   These   animals   had   no histological   signs   of   cerebral lesions and parasite burden assessed by quantitative real-time PCR was not detected. Both vaccine preparations including Providean-AVEC ® as adjuvant, limited N. canimum multiplication. Notably, the use of this adjuvant induced protection even with only atenth of antigen payload compared to vaccines containing other adjuvants. Using adjuvants to specifically activate dendritic cells, combined with a careful antigen selection can enhance cellular responses to inert N. caninum vaccines.