possible to ensure the specificity of rabbit antisera to a virus before the virus has been isolated? Similarly, how was it possible, before viral isolation, to ascertain that patient serum used to test material from the cultures did indeed interact specifically with the same virus? (c ) The OSI found the claim that "the culture" was continuously producing HTLV-III (RT activity), was incorrect since the culture was "reinoculated on at least two occasions" with more supernatant.(11,22) In the second paper,(7) the authors describe their attempt to isolate HTLV-III from mitogenically stimulated T-cell cultures obtained from 115 patients with AIDS, pre-AIDS and clinically normal homosexual men. In Table I entitled "Detection and Isolation of HTLV-III from patients with AIDS and pre-AIDS", they state: "Samples exhibiting more than one of the following were considered positive: repeated detection of a Mg2+- dependent reverse transcriptase activity in supernatant fluids;virus observed by electron microscopy [retroviral particles in the cultures]; intracellular expression of virus-related antigens detected with antibodies from seropositive donors or with rabbit antiserum to HTLV-III; or transmission of particles". By transmission of particles was meant detection of reverse transcriptase or particles in cultures of "human cord blood, bone marrow, or peripheral blood T lymphocytes", cultured with concentrated fluids from the cell cultures from tissues obtained from AIDS patients. In further experiments (8,9): 1. Lysates of the H4/HTLV-III and H17/HTLV-III "infected" cell lines were tested with patient sera using the Western blot (WB) technique.[Footnote 1]; 2. "The specificity of these reactions [for HTLV-III] was studied by comparing lysates of H4/HTLV-III and H17/HTLV-III with lysates of the same clones, H4 and H17, before viral infection (Fig.2A). No antigen from uninfected clones reacted with the sera, with the exception of a protein with a m...
