INFECTION OF RATS WITH HUMAN T-CELL LEUKEMIA-VIRUS TYPE-1 - SUSCEPTIBILITY OF INBRED STRAINS, ANTIBODY-RESPONSE AND PROVIRUS LOCATION

The susceptibilities of different strains of inbred rats to infection with the human T-cell leukemia virus (HTLV-I) after inoculation of hum an HTLV-I producer cell lines were compared. The Fisher F344 and Brown Norway strains developed the highest antibody response to HTLV-I, whi le the Lewis and BB strains were low responders. Antibodies against th e HTLV-I gag proteins, and env gp21 but not env gp46, were detected in Western blots with sera from HTLV-I-infected Fischer F344 and Brown N orway rats. These sera were inactive in an in vitro syncytium-formatio n inhibition test. The HTLV-I provirus was detected by polymerase chai n reaction in all Fischer F344, and some Lewis and Brown Norway rats, but not in the BB, which lack CD8(+) T lymphocytes. The most frequent locations of the HTLV-I provirus in the Fischer F344, Lewis and Brown Norway rats at 12 weeks after infection were the peripheral blood mono nuclear cells (PBMC) and spinal cord. In a second experiment in Brown Norway rats, the provirus was again detected in the PBMC of rats at 12 weeks, but not at 22 weeks, and among the other organs tested at 22 w eeks the sympathetic nerve ganglia were positive. It is concluded that HTLV-I infection occurs in adult rats, but is suppressed with time.