Antigens related to three core proteins of HTLV‐I (p24, p19 and p15) and their intracellular localizations, as defined by monoclonal antibodies

Abstract

Three distinct monoclonal antibodies (MAbs) specific for human T-cell leukemia virus type-I (HTLV-I) core proteins with molecular weights of 24 kDa (p24), p19 or p15 were produced, characterized and compared. These antibodies were named NOR-1 (anti-p24, IgG2a), GIN-7 (anti-p19, IgG2b) and FR-45 (anti-p15, IgG2a). Immunofluorescence assay showed that they reacted specifically with methanol-fixed cells of virus-bearing cell lines, and that only GIN-7 bound, albeit weakly, to the surface of a small percentage of viable cells. Like natural antibodies to HTLV-I in human serum, GIN-7 stained the fixed cells brightly and diffusely, and gave more intense fluorescence than NOR-1 and FR-45, which stained restricted areas of the cells. NOR-1, GIN-7 and FR-45 specifically precipitated core proteins p24, p19 and p15, respectively, from a lysate of HTLV-IMT-2 labelled with 35S-cysteine. NOR-1 precipitated p53, p36, and p24, GIN-7 precipitated p53, p32, p28 and p19, and FR-45 precipitated p53, p36, and p15 from a lysate of 35S-cysteine-labelled MT-2 cells. GIN-7 also precipitated p32, p28 and p19 from a lysate of MT-2 cells, labelled by surface iodination, but NOR-1 and FR-45 did not detect any proteins in this lysate. GIN-7 also detected p28 in 3H-glucosamine-labelled MT-2 cells. Antibody binding competition assay showed that the sera of ATL patients significantly interfered with the binding of NOR-1 and GIN-7 but not with that of FR-45, to antigens of disrupted virus of MT-2 cells. This complete set of MAbs against the HTLV-I gag gene products is useful for biological and functional studies of the HTLV-I core proteins.

Immunoelectron microscopic localization of human T-cell leukemia virus type-I antigens.

“…This p68X seems to be the same as gp68, which has been considered to be the env precursor protein in MT-2 cells, but the identification must await further study. The anti-p19 MoAb was shown to react with p19 in HUT 102, and with p19 and p28 in MT-2 as previously mentioned (40,41). Anti-p19 MoAbs from some clones were shown to react with, in addition to p19, normal thymic epithelial cells and some of the embryonal cells (7,27,38).…”

“…p27x-III was suggested to control the level of gag mRNA by post-transcrip-253 tional modulation (10). ATL-associated antigens (ATLA) reactive with sera from ATL patients were shown to be localized in the cytoplasm of HTLV-I-producing Tcells by means of immunofluorescence (8,41). p40X was shown to be contained in both the nuclei and the cytoplasm by means of immunofluorescence and cell fractionation (5,12,33,43).…”

Human T-lymphotropic Virus, Type 1, Tax Protein Triggers Microtubule Reorientation in the Virological Synapse

“…Antibodies and Reagents-To detect HTLV-1 proteins in infected cells, we used the mouse IgG3 monoclonal antibody (mAb) directed against HTLV-1 Tax protein (Lt-4) (20) and the mouse IgG2b mAb directed against HTLV-1 Gag p19 (Gin7) (21). The microtubule network was stained with the anti-␤-tubulin (CY 3-conjugated) mAb TUB2.1 obtained from Sigma.…”

Potential immunogenicity of adult T cell leukemia cells in vivo

“…To detect intracellular HTLV-I antigens, mouse monoclonal antibodies (mAbs), Lt-4 (anti-p40 Tax, mouse IgG3), 34 NOR-1 (anti-p24 and p53 Gag; mouse IgG1), 35 GIN-7 (anti-p19, p28 and p53 Gag; mouse IgG2b) 35 and biotinylated GIN-7 were used.…”