Growth properties of a feline immunodeficiency virus mutant which lacks an AP-1 binding site in primary peripheral blood mononuclear cells.

Thirty-one base pairs (bp) containing putative AP-1 and AP-4 binding sequences in the U3 region of feline immunodeficiency virus (FIV) long terminal repeat (LTR) were deleted from an infectious molecular clone of FIV for construction of a mutant virus, and the replication rate and the cytopathogenic activity of the virus were compared with those of the wild type virus in concanavalin-A (Con-A) stimulated primary feline peripheral blood mononuclear cells (fPBMCs). It was found that the replication rate and cytopathogenic activity of the mutant were almost the same as those of the wild type. The deletion of the mutant virus was stable during the infection experiments. From these data, we concluded that the 31 bp fragment in the LTR is not required for the replication of FIV in Con-A stimulated primary fPBMC.