Compounds targeting the nucleocapsid protein zinc fingers inactivate HIV while preserving conformational integrity of virion surface proteins

We have described compounds that inactivate HIV by disruption of nucleocapsid protein (p7) zinc finger motifs. Primary isolates or laboratory strains of HIV were treated with one such compound, aldrithiol-2 (2,2'dipyridyl disulfide) in PBS for 1 hr at 37 degrees C. Serial dilutions of treated or sham-treated control virus were then tested for infectivity by titration on replicate normal human PBMC PHA blast cultures (20 replicates/virus dilution). Day 11 supernatants were tested for p24 antigen content as evidence of productive infection, and residual infectious units were calculated. Parallel aliquots of treated or sham-treated virus dilutions were added to highly purified (greater than 98%) resting human T lymphocytes, along with the superantigen staphylococcal enterotoxin A (SEA). SEA-triggered proliferation in such cultures is dependent on the presence of conformationally intact MHC Class II determinants to present SEA to T cell receptors and was measured at 72 hrs by [3H]-thymidine incorporation. In such resting T cell cultures the necessary MHC Class II determinants can be provided by host cell derived proteins incorporated into the envelopes of budded HIV-1 virions. Aldrithiol-2 treatment of both primary and laboratory isolates of HIV at greater than or equal to 100 mM reduced infectivity by at least 3-4 logs. Despite this decrease in infectivity, virus preparations treated with 100 mM aldrithiol-2 supported good SEA-triggered proliferative responses, indicating that virion-associated MHC Class II proteins were present on the surface of virions in functionally intact conformation. Other virus inactivation treatments such as heating (56 degrees C) diminished infectivity but also eliminated the ability to support SEA-stimulated proliferative responses. Aldrithiol-2 or other related compounds may provide a convenient means for inactivating HIV while preserving the integrity of virion surface proteins, an important consideration for some studies.

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