DETECTION OF HIV-SPECIFIC DNA-SEQUENCES IN EPIDERMAL LANGERHANS CELLSINFECTED IN-VITRO BY MEANS OF A CELL-FREE SYSTEM

As dendritic antigen-presenting cells in skin and mucous membranes, La ngerhans cells (LC) are found in areas at risk of inoculation by the h uman immunodeficiency virus (HIV). LC have been reported as targets fo r HIV-1. The aim of the present study was to investigate whether LC ca n be experimentally infected by HIV provided by a cell-free infection system. A cell-free suspensions was prepared from viral particles prov ided by chronically infected cell lines (U937 or H9 cells) by low-spee d centrifugation followed by 0.45-mu m filtration. LC-enriched epiderm al cell (EC) suspensions with no CD3(+) cells (assessed by flow cytome try and electron microscopy) and uninfected U937 cells (cell-free infe ction system control) were infected with two isolates (HTLVIII-B and R F). The infectiousness of the cell-free virus fluids was controlled on U937 cells where proviral DNA was amplified (gag, pol, and env gene s equences by the polymerase chain reaction, PCR) and release of virus p articles into the supernatant was controlled either by measure of the reverse transcriptase (RT) activity or detection of viral RNA amplifie d by RT-PCR for the gag gene sequences). Proviral DNA (gag gene sequen ces) was found in LC-enriched epidermal cellular DNA from day 4 post-i nfection with isolate HTLVIII-B and from day 7 with isolate RF. Althou gh the RT activity did not reach a significantly high level, viral RNA was found in the supernatant of LC-enriched EC cultures at the same t ime as proviral DNA was detected in LC. The findings indicate that the cell-free virus-infection.