A binding assay to identify HIV (LAV) target cells

Abstract

Summary As an approach to identifying HIV (LAV) target cells, viral particles were labelled with fluorescein isothiocyanate (FITC-HIV) and the binding of FITC-HIV to lymphocytes and HIV permissive cells was analysed by fluorescence microscopy and by flow cytometry. No B cells or T8 cells were stained by FITC-HIV in contrast to normal CD4 + lymphocytes and HIV permissive cells. Preincubation with either unlabelled HIV or anti-CD4 monoclonal antibodies blocked further FITC-HIV binding on these cells, indicating the specificity of this binding assay. Similarly, pre-incubation of T lymphocytes with FITC-HIV prevented a subsequent HIV infection. Ten per cent of normal CD4 + lymphocytes and CD4 − bone marrow immature T cells as well as 10 to 30 % of CD4 + cell lines were stained by FITC-HIV. These results provide an experimental model for the further study of HIV (LAV) receptor(s) and for determining whether, in addition to CD4, other molecules are involved in HIV functional receptors.