Coexistence of fusion receptors for human T-cell leukemia virus type-I (HTLV-I) and human immunodeficiency virus type-1 (HIV-1) on MOLT-4 cells.
Human immunodeficiency virus type-1 (HIV-1) and human T-cell leukemia virus type-I (HTLV-I) have a similar tropism for target cell types, especially for CD4+ T cells. In this study, we provide evidence that receptors of these two viruses exist independently on the target cell. We established an HTLV-I-producing CD8+ T cell line (ILT-8M2) with a remarkable cell fusion capacity. When cocultured with MOLT-4 cells, ILT-8M2 cells induced giant syncytia more efficiently than any other tested HTLV-I-producer cell lines. In contrast to other HTLV-I-producers, ILT-8M2 cells were minimally susceptible to cytopathic effects of HIV-1 due to very low expression of CD4, although they were able to be persistently infected by HIV-1. The indicator MOLT-4 cells are known to respond well to HIV-1-induced cell fusion, but they lose this ability if they become persistently infected with HIV-1 because of the reduction of CD4 receptor expression. ILT-8M2 was, however, still capable of inducing syncytia with the MOLT-4 cells persistently infected by HIV-1 (MOLT-4/IIIB). This syncytium formation was dependent on the HTLV-I-envelope, as it was inhibited by HTLV-I-positive human sera or a monoclonal antibody to HTLV-I gp46 but not by monoclonal antibodies to HIV-1 gp120 or CD4. Moreover, ILT-8M2 cells persistently infected by HIV-1 (ILT-8M2/IIIB) induced both HTLV-I- and HIV-1-mediated syncytia with uninfected MOLT-4 cells. These results suggest that HTLV-I induces cell fusion utilizing receptors on the target cells independent of HIV-1-receptors.
Kannagi
M
M
Department of Biodefence and Medical Virology, Kumamoto University Medical School, Japan.
Kuroda
M J
MJ
Maeda
Y
Y
Harada
S
S
D016827:CD8 Antigens; D002459:Cell Fusion; D002460:Cell Line; D006800:Deltaretrovirus Infections / Q000150:complications / Q000276:immunology; D015658:HIV Infections / Q000150:complications / Q000276:immunology; D015497:HIV-1 / Q000276:immunology / Q000472:pathogenicity; D015368:Human T-lymphotropic virus 1 / Q000276:immunology / Q000472:pathogenicity; D006801:Humans; D010641:Phenotype; D011533:Proviruses; D015728:Receptors, HIV / Q000032:analysis*; D011991:Receptors, Virus / Q000032:analysis*; D012190:Retroviridae / Q000276:immunology / Q000472:pathogenicity*; D012192:Retroviridae Infections / Q000150:complications / Q000276:immunology / Q000382:microbiology*; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000382:microbiology*; D014407:Tumor Cells, Cultured; D014779:Virus Replication
D016827:CD8 Antigens; D015728:Receptors, HIV; D011991:Receptors, Virus