Bovine interleukin 2 (IL-2) production and activity on bovine and murine cell lines

Long-term growth of T cell cultures requires addition of Interleukin 2 (IL-2). In order to maintain bovine cultures, optimal conditions for bovine IL-2 production were defined using peripheral blood mononuclear cells (PBM). Irradiation and preculture enhanced IL-2 production possibly by reducing suppressor activity. IL-2 activity was also detected in Bovine Herpesvirus Type 1-stimulated cultures. Unlike mitogen-stimulated cultures, a wide variation in IL-2 activity was seen between supernatants produced by virus-stimulated cells from different animals indicating the clonal nature of antigen specific cells from individuals. Bovine IL-2-dependent cells used to quantitate IL-2 activity were characterized as: PNA, esterase negative, H4+ (anti Ia-like), B29+ (anti-pan T cell), and C5- (anti-monocyte). The observations that bovine IL-2 can maintain activated murine cells, CTLL-20 and HT-2, could lead to the replacement of rat IL-2 with bovine IL-2 in long-term murine cultures. Conditions described here result in large volumes of active medium.