BOVINE LENTIVIRUS INDUCES EARLY TRANSIENT B-CELL PROLIFERATION IN EXPERIMENTALLY INOCULATED CATTLE AND APPEARS TO BE PANTROPIC

Bovine immunodeficiency-like virus (BIV) was first isolated in 1972 (M . J. VanDerMaaten et al., J. Natl. Cancer Inst. 49:1619-1657, 1972). M uch work has been done on the molecular characterization of BIV in stu dies using the original BIV R29 isolate; however, R29 is believed to b e attenuated since it no longer causes either mononuclear cell number increases or detectable enlargement of lymphatic nodules in experiment ally infected cattle. The host cell tropism and changes in host periph eral blood lymphocyte populations following infection with BTV are unk nown. Recently, we isolated and characterized a held isolate of BIV, F L112 (D. L. Suarez et al., J. Virol. 67:5051-5055, 1993) that causes a transient, mononuclear cell lymphocytosis in experimentally infected cattle. In the present study, cattle were inoculated with BIV FL112, a nd data from flow cytometry showed that BIV causes a B-cell lymphocyto sis with no consistent, significant changes in other mononuclear cell populations, including CD3(+), CD4(+), and CD8(+) cells. Cell sorting and PCR amplification were used to show that BIV may be pantropic. Pro viral DNA was present in CD3(+), CD4(+), CD8(+), and B-cells, monocyte s, and WC1 cells (gamma/delta T cells, null cells) by 3 to 6 days post inoculation and also at 2.5 years postinoculation.