Lymphocyte blastogenesis in bluetongue virus or Mycobacterium bovis-inoculated bovine fetuses.

Bovine fetuses were inoculated with Mycobacterium bovis, bluetongue virus or placebo at approximately 125 days of gestation, and blastogenic responses of peripheral blood lymphocytes and lymph node cells were determined at various time intervals after inoculation. Lymphocytes from all fetuses were stimulated by phytohemagglutinin, concanavalin A, and pokeweed mitogen, and peripheral blood lymphocytes gave consistently greater stimulation indices than did prescapular lymph node cells. Bluetongue virus infection did not consistently suppress mitogen induced lymphocyte blastogenesis. Lymphocytes taken from fetuses at 20 or 50 days after Mycobacterium bovis inoculation were not stimulated by purified protein derivative (PPD), whereas lymphocytes taken from adult cattle at similar intervals after Mycobacterium bovis inoculation were stimulated by PPD. Although lymphocytes from bovine fetuses may be stimulated by mitogens, antigen specific blastogenesis to a known inducer of cellular immunity was not detected by 175 days of gestation.