Search

The results of the RV144 vaccine clinical trial showed a correlation between high level of anti-V1V2 antibodies (Abs) and a decreased risk of acquiring HIV-1 infection. This turned the focus of HIV vaccine design to the induction of elevated levels of anti-V2 Abs to increase vaccine efficacy. In plasma samples from HIV-1 infected Cameroonian individuals, we observed broad variations in levels of anti-V2 Abs, and 6 of the 79 plasma samples tested longitudinally displayed substantial deficiency of V2 Abs. Sequence analysis of the V2 region from plasma viruses and multivariate analyses of V2 characteristics showed a significant difference in several features between V2-deficient and V2-reactive plasma Abs. These results suggest that HIV vaccine immunogens containing a shorter V2 region with fewer glycosylation sites and higher electrostatic charges can be beneficial for induction of a higher level of anti-V2 Abs and thus contribute to HIV vaccine efficacy. [ABSTRACT FROM AUTHOR]

Abstract: To investigate essential factors that determine the efficacy of vaccines against lentiviruses, an effective attenuated equine infectious anemia virus (EIAV) vaccine strain and a proviral derivative of the vaccine were compared with respect to differences in inducing protective immunity. Although these two strains replicated equally well in vitro and in vivo, the proviral strain induced significantly less protection from disease and infection caused by viral challenge and significantly lower specific neutralizing capability. These findings indicated that the proviral strain had lost the ability to stimulate immune protection compared to the parental vaccine strain. A further analysis of the envelope gp90 gene variation revealed that compared to the proviral strain, the vaccine strain displayed a wide sequence diversity in immunogen composition. Thus, we inferred that the differences in immunogen composition might be the major cause for the failure of the proviral derivative to elicit the immune protection induced by the parental strain. [ABSTRACT FROM AUTHOR]