Heterokaryons Formed between a Rat Myeloma and a Mouse Fibroblast Are Permissive for Entry of HIV Type 1

Abstract

Expression of CD4 is not sufficient for cellular susceptibility to HIV-1 entry. The majority of nonprimate cells appear to lack a factor that plays an accessory role to CD4 during virus-cell fusion. We have previously reported CD4-dependent entry in rat myeloma Y3 cells, and here we show that Y3 and CD4-expressing mouse L929 cells fuse spontaneously to produce heterokaryons susceptible to entry by HIV-1. The results suggest that a putative accessory factor necessary for entry of HIV-1 into cells is expressed by the nonprimate Y3 cell line.