Quantitative assays for evaluation of HTLV-III inactivation procedures: tri(N-butyl)phosphate:sodium cholate and beta-propiolactone.

Human T-lymphotropic retrovirus type III (HTLV-III) can be quantitatively assayed for infectivity by inoculation of serial dilutions into cultures of the H-9 cell line and testing for reverse transcriptase in the culture supernatants. Sequential harvests revealed that 14 days of incubation of cultures fed twice weekly was sufficient to reveal maximal titers. Stocks prepared from unconcentrated H9:HTLV-IIIb supernatants have contained from 10(4.