Genotype E of small ruminant lentivirus has been recently described in goats from different breeds in Italy. In particular, Roccaverano strain is being considered low pathogenic in vitro and in vivo. In fact previous studies showed that major virulence determinant is likely located in the env gene, affecting virus entry and tissue distribution. Moreover animals co-infected with genotype E and genotype B (CAEV-like) strains do not seem to develop arthritis, suggesting a possible protective role of the former. We demonstrated that experimental infection of genotype E induced cytotoxic-T-lymphocyte (CTL) activity in infected animals, surprisingly not strain specific, being higher against genotype B infected antigen presenting cells (APCs). To further support a protective role of Roccaverano strain, eight goats were infected (immunized) with Roccaverano strain and challenged 20 weeks later with CAEV-CO ; an equal number of goats were challenged with CAEV-CO, without vaccination; further 4 animals were used as negative control in all subsequent experiments. Cinetic of proviral load of challenge strain was evaluated in all groups by qPCR in 14 time points. Macroscopic and microscopic lesions were evaluated during necropsy and by histopathological examination of samples collected from different organs. Preliminary evaluation after 52 weeks after challenge revealed lower proviral load of challenge strain in vaccinated animals, being statistically supported between 141 and 274 d.p.i. . This study shows for the first time that animals experimentally infected with Roccaverano strain and challenged with a virulent CAEV strain, develop an adaptive immune response able to reduce CAEV-CO proviral load, reaching in some cases the undetectable level.
Immunization of goats against CAEV infection using Roccaverano strain as live attenuated vaccine
PREZIUSO, Silvia;
2011-01-01
Abstract
Genotype E of small ruminant lentivirus has been recently described in goats from different breeds in Italy. In particular, Roccaverano strain is being considered low pathogenic in vitro and in vivo. In fact previous studies showed that major virulence determinant is likely located in the env gene, affecting virus entry and tissue distribution. Moreover animals co-infected with genotype E and genotype B (CAEV-like) strains do not seem to develop arthritis, suggesting a possible protective role of the former. We demonstrated that experimental infection of genotype E induced cytotoxic-T-lymphocyte (CTL) activity in infected animals, surprisingly not strain specific, being higher against genotype B infected antigen presenting cells (APCs). To further support a protective role of Roccaverano strain, eight goats were infected (immunized) with Roccaverano strain and challenged 20 weeks later with CAEV-CO ; an equal number of goats were challenged with CAEV-CO, without vaccination; further 4 animals were used as negative control in all subsequent experiments. Cinetic of proviral load of challenge strain was evaluated in all groups by qPCR in 14 time points. Macroscopic and microscopic lesions were evaluated during necropsy and by histopathological examination of samples collected from different organs. Preliminary evaluation after 52 weeks after challenge revealed lower proviral load of challenge strain in vaccinated animals, being statistically supported between 141 and 274 d.p.i. . This study shows for the first time that animals experimentally infected with Roccaverano strain and challenged with a virulent CAEV strain, develop an adaptive immune response able to reduce CAEV-CO proviral load, reaching in some cases the undetectable level.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
