Vaccine 30 (2012) 1124–1131 Contents lists available at SciVerse ScienceDirect Vaccine j ourna l ho me pag e: www.elsevier.com/locate/vaccine The immune enhancement of a novel soy lecithin/-glucans based adjuvant on native Neospora caninum tachyzoite extract vaccine in mice Florencia Celeste Mansilla a,1 , Olga Lucía Franco-Mahecha a,1 , María Ángeles Lavoria a , Dadín Prando Moore b , Adrián Nicolás Giraldez a , Marcela Elvira Iglesias c , Maximiliano Wilda a , Alejandra Victoria Capozzo a,∗,1 a Instituto de Ciencia y Tecnología Dr. César Milstein, Saladillo 2468, 1440 Ciudad Autónoma de Buenos Aires, Argentina b Instituto Nacional de Tecnología Agropecuaria (INTA) Balcarce, 7620 Balcarce, Buenos Aires, Argentina c Tecnovax S.A. Luis Viale 2835, 1416 Ciudad Autónoma de Buenos Aires, Argentina a r t i c l e i n f o Article history: Received 16 August 2011 Received in revised form 1 December 2011 Accepted 3 December 2011 Available online 14 December 2011 Keywords: Neospora caninum vaccine Adjuvants Mouse model a b s t r a c t Efficient, cost-effective and safe Th1-immunity-inducing vaccine formulations are paramount for achiev- ing protection against Neospora caninum. In this study, a new adjuvant (Providean-AVEC ® ) was used in the development of a N. caninum vaccine and evaluated in a mouse model. Soluble N. caninum tachy- zoite native protein extract (sNcAg) was selected as vaccine antigen based on its capacity to activate production of pro-inflammatory cytokines on dendritic cells. Vaccines containing 4 and 0.4 g of sNcAg, and Providean-AVEC ® , ISCOM-Matrix or aluminum hydroxide (Alum) were tested in BALB/c mice. While mice vaccinated with 4 g 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 g sNcAg) or with either low or high payload Providean-AVEC ® formulations (0.4 g and 4 g sNcAg, respectively) elicited higher IgG2a than IgG1 serum levels, and IFN- anamnestic responses 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. Vaccine preparations including Providean-AVEC ® as adjuvant limited N. canimum multiplica- tion even with only a tenth 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. © 2011 Elsevier Ltd. All rights reserved. 1. Introduction The intracellular protozoan parasite Neospora caninum is a cyst- forming coccidian recognized worldwide as an important cause of reproductive failure in cattle [1,2]. Neosporosis is generally latent and asymptomatic in non-pregnant cattle, although the conse- quences of infection in a pregnant cow can be abortion, birth of a weak calf or birth of a clinically healthy but persistently infected calf [3]. Currently, there is no effective method for controlling neosporosis, apart from intensive farm management to reduce the probability of infection. Therefore, the development of an effective ∗ Corresponding author. Tel.: +54 11 44816684; fax: +54 11 46866225. E-mail addresses: alejandra capozzo@yahoo.com.ar, acapozzo@cnia.inta.gov.ar (A.V. Capozzo). 1 Current address: Instituto de Virología (INTA), Centro de Investigaciones en Ciencias Veterinarias y Agronómicas, N. Repetto y De los Reseros de S/N. Hurlingham, 1686 Buenos Aires, Argentina. Tel.: +54 11 44816684. and safe vaccine against N. caninum is of great importance due to the significance of the economic losses in the dairy and beef industries [4]. Unlike other protozoan parasites, the development of an effec- tive vaccine against N. caninum may be feasible, since infection is mainly controlled by CD4+ T cell-dependent responses elicited along the IL-12/IFN-/iNOS effector axis [5,6]. Another advantage that favors the development of new N. caninum vaccines is the avail- ability of a mouse model. The BALB/c mouse model has been widely used to evaluate vaccines [7–9] and to study aspects of N. caninum infection [8,10–17] offering a tool to characterize and compare the virulence of N. caninum isolates [13]. Application of the mouse model demonstrated that potent adjuvants can boost immunogenicity and induce cell mediated immunity against N. caninum antigens. Rojo-Montejo et al. [8] showed that efficacy of immunization with inactivated tachyzoites can significantly vary depending on the adjuvant, the antigen dose, and the phase of N. caninum infection during which the vaccine is tested. In this report, 5 × 10 5 inactivated tachyzoites formulated 0264-410X/$ – see front matter © 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.vaccine.2011.12.007