A rodent cell line permissive for entry and reverse transcription of human immunodeficiency virus type 1 has a pre-integration block to productive infection

Replication of human immunodeficiency virus type 1 (HIV-1) is restricted to CD4-expressing primate cells. This tropism may be due partly to the absence from non-primate cells of a species-specific factor which has an accessory role to CD4 during virus penetration. In this study we describe a rat B lymphocyte cell line in which there is efficient CD4-dependent entry of HIV-1. However, this cell line has a block to productive infection of HIV-1 at a stage between reverse transcription and integration. Our results demonstrate that the putative accessory factor for HIV-1 penetration is not restricted to primate cells and that there is a novel, uncharacterized cell-virus interaction at a stage between penetration and integration.