Protective efficacy of vaccination with Neospora caninum multiple recombinant antigens against experimental Neospora caninum infection

Abstract

Protective efficacy of vaccination with Neospora caninum multiple recombinant antigens against N. caninum infection was evaluated in vitro and in vivo. Two major immunodominant surface antigens (NcSAG1 and NcSRS2) and two dense granule proteins (NcDG1 and NcDG2) of N. caninum tachyzoites were expressed in E. coli, respectively. An in vitro neutralization assay using polyclonal antisera raised against each recombinant antigen showed inhibitory effects on the invasion of N. caninum tachyzoites into host cells. Separate groups of gerbils were immunized with the purified recombinant proteins singly or in combinations and animals were then challenged with N. caninum. Following these experimental challenges, the protective efficacy of each vaccination was determined by assessing animal survival rate. All experimental groups showed protective effects of different degrees against experimental infection. The highest protection efficacy was observed for combined vaccination with NcSRS2 and NcDG1. Our results indicate that combined vaccination with the N. caninum recombinant antigens, NcSRS2 and NcDG1, induces the highest protective effect against N. caninum infection in vitro and in vivo.

Characterisation of NcGRA7 and NcSAG4 proteins: Immunolocalisation and their role in the host cell invasion by Neospora caninum tachyzoites

“…This conclusion would be in agreement with the normal function assigned to GRA proteins as they are targeted to the vacuolar space very shortly after invasion . Other authors have also found an NcGRA7-related inhibition effect on invasion (Augustine et al 1999, Cho et al 2005 thus supporting this idea.…”

“…In particular, GRA7 is a highly immunogenic, dense granule protein in both T. gondii and N. caninum (Lally et al 1997, Fischer et al 1998, Vonlaufen et al 2004, which has been effectively employed as a diagnostic tool (Aguado-Martínez et al 2008). Moreover, although GRA proteins appear to be related to intracellular parasite development, previous studies Characterisation of Neospora caninum NcGRA7 and NcSAG4 proteins 305 revealed that NcGRA7 might be involved in the initial host cell invasion process of N. caninum (Augustine et al 1999, Cho et al 2005.…”

Intraperitoneal and intra-nasal vaccination of mice with three distinct recombinantNeospora caninumantigens results in differential effects with regard to protection against experimental challenge withNeospora caninumtachyzoites

“…Various strategies have been used to enhance the post-vaccination immune response, such as application of multiple recombinant antigens in one shot (Cho et al 2005 ;Ellis et al 2008), different adjuvants and dosages, various formulations and different routes of administration (Innes and Mattsson, 2007).…”

Immunization with Oligomannose-Coated Liposome-Entrapped Dense Granule Protein 7 Protects Dams and Offspring fromNeospora caninumInfection in Mice

“…Previous studies have shown that immune responses to NcGRA7 have a protective role in preventing the vertical transmission of N. caninum in a pregnant mouse model using plasmid DNA, as well as acute fatal infection of N. caninum in a gerbil model using a recombinant NcGRA7 protein expressed by E. coli (5,24,28). In contrast, Brucella abortus vaccine strain RB51 expressing the NcGRA7 gene did not show any vaccine efficacy against cerebral infection with N. caninum (48).…”