IN-VITRO INFECTION OF HUMAN EPIDERMAL LANGERHANS CELLS WITH HIV-1

Epidermal Langerhans' cells (LC) from human immunodeficiency virus typ e-1 (HIV-1)-infected patients harbour HIV-1 proviral DNA and RNA. In t he present study, we investigated whether LG from epidermis of normal, HIV-seronegative subjects could be infected in vitro with HIV-1. Epid ermal cells (EC) spontaneously detached from epidermal sheet cultures were enriched for LG (10-25% of CD1a(+)/CD4(+) cells), deprived of con taminating T cells and then incubated with HIV-1(IIIB). After 24 hr, p urified LC and LC-depleted EG fractions were obtained by immunomagneti c separation. Polymerase chain reaction (PGR) analysis showed the pres ence of HTV-1 proviral DNA (gag) only in purified LC. In addition, LC- enriched EC, purified LG, LC-depleted EG or the non-permissive cell li ne, TF-1, the latter having being previously challenged with HIV-1(III B) for the same length of time as the EC, were co-cultivated with C816 6 cells, and the co-cultures assessed for the presence of HIV DNA by P CR. Go-cultures of C8166 cells with purified LC or LC-enriched EG prev iously exposed to HIV-1(IIIB) exhibited a time-dependent increase in H IV proviral DNA. In contrast, PCR analysis of C8166 cells co-cultured with either LC-depleted EC or TF-1 cells gave negative results. Finall y, C8166 cells co-cultured with HIV-infected LC formed syncytia, showe d membrane budding and released numerous retroviral particles. The res ults indicate that LC from normal subjects can be infected in vitro wi th HIV and can transmit infection to myeloid cells. This in vitro mode l may help in understanding the regulation of HIV infection of LC.