Lymphocyte transformation abnormalities in bovine immunodeficiency-like virus infected calves.

Bovine immunodeficiency-like virus (BIV) is a lentiviral pathogen of cattle which is genetically and antigenically related to the human immunodeficiency virus (HIV-1). To determine the impact of BIV infection on the bovine immune system we studied the lymphocyte transformation responses of male Holstein calves inoculated with BIV strain R-29 to three mitogens: pokeweed mitogen (PWM), concanavalin A (Con A), and phytohemagglutinin (PHA) at two and six months post-infection. By six months post-inoculation the response to all three mitogens was diminished compared to control animals and remained depressed 10 months post-inoculation. These results demonstrate that a functional impairment of lymphocytes can be observed early in the course of BIV infection, and prior to the onset of overt clinical disease.