Inactivation of HIV-1 infectivity with preservation of conformational and functional integrity of virion surface proteins

HIV-1 virions that had been rendered non-infectious, but which preserved the conformational integrity of virion surface proteins, would be an interesting candidate vaccine antigen and a useful reagent for experimentally probing the postulated involvement of virion surface proteins in HIV-1 pathogenesis. We have used the disulfide compound aldrithiol-2 to covalently modify the essential zinc finger motifs in the nucleocapsid protein (NC7) of HIV-1 virions, thereby inactivating infectivity. The inactivated virus was not detectably infectious in limiting dilution culture (greater than 3 logs inactivation, based on comparison with pretreatment stock). However, in contrast to virions inactivated with conventional methods such as heat or formalin treatment, both viral and host cell derived proteins on virion surfaces retained conformational and functional integrity. Thus, the MHC Class II molecules on the surface of aldrithiol-2 treated virions produced from MHC Class II positive cells retained the ability to support Class II independent, superantigen triggered proliferative responses by resting T lymphocytes. Immunoprecipitation of treated virions was comparable to precipitation of matched untreated virus, even using antibodies to conformational determinants on gp120. Aldrithiol-2 treated virions bound to CD4+ target cells comparably to matched untreated virus. These findings indicate that inactivation via this method results in loss of infectivity with presentation of conformational and functional integrity of virion surface proteins. Results of immunological and functional studies using such virus preparations will be presented, with reference to pathogenesis and vaccine development.

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