Expression of human immunodeficiency virus type 1 (HIV-1) gag antigens on the surface of a cell line persistently infected with HIV-1 that highly expresses HIV-1 antigens

Persistent infection of MT-4 cells by human immunodeficiency virus type 1 becomes increasingly likely with in vitro serial passage of wild-type but not nef mutant virus

“…A cell-free fraction was prepared by low-speed centrifugation, followed by centrifugation of the supernatant at 70000 r.p.m, for 30 min at 4 °C in a TLA-100.3 rotor (Beckman) to pellet virus particles and give a supernatant containing the soluble protein fraction. The cell and virus particle lysates in lysis buffer (0-5% Nonidet P40, 0.5% sodium deoxycholate, 0-05 M-Tris HC1 pH 7.2, 0.1 M-NaC1, 1 mM-EDTA, 1 mM-PMSF) and the soluble protein fraction diluted with lysis buffer were immunoprecipitated with the serum from an HIV-1 seropositive subject as described previously (Ikuta et al, 1989). Proteins in the immunoprecipitates were analysed by SDS PAGE (separation gel, 10 to 15% linear gradient acrylamide; spacer gel, 4% acrylamide) as described previously (Ikuta et al, 1989).…”

“…An indirect IF test was carried out using cell smears fixed with cold acetone. The cells were incubated with a 500-fold serum dilution from an HIV-1 seropositive subject (IF titre 1:4096) and then reacted with a 40-fold dilution of fluorescein isothiocyanate (FITC)-conjugated rabbit anti-human IgG (Dakopaus) as described previously (Ikuta et al, 1989).…”

Antibody-Dependent Cellular Cytotoxicity via Humoral Immune Epitope of Nef Protein Expressed on Cell Surface

“…Rook et al (10) described that Ab reactivity with the p24 (Gag) protein of patient's serum correlates inversely with disease progression. It has been reported that Gag proteins are expressed on the cell surface (27,28); nevertheless, the inductions of ADCC via Gag have never been succeeded (29). And, furthermore, there has been no evidence that Pol proteins are expressed on the HIV-1-infected cells; therefore, Pol Ags could not be exposed to the extracellular enviroment as ADCC target.…”

Highly conserved epitope domain in major core protein p24 is structurally similar among human, simian and feline immunodeficiency viruses

“…Therefore it is of particular importance to clarify, at the molecular level, the antigenic structure of p24 and p17, particularly those expressed on the surface of HIV-l-infected cells. In our previous work, we demonstrated the surface expression of the HIV-1 gag p24 and p17 antigens on persistently HIV-l-infected cells by immunofluorescence and radioimmune techniques with murine anti-gag monoclonal antibodies (MAbs) (Ikuta et al, 1989). The regions recognized by these MAbs must be on the surface of HIV-l-infected cells and could be exposed to the host immune systems, implying that they could be potential candidates for vaccines, and could therefore prevent the onset of AIDS.…”