In vitro stimulation of bovine circulating lymphocytes by parainfluenza type 3 virus.

Bovine circulating lymphocytes from animals sero-positive to parainfluenza-3 virus (PIV-3) could be stimulated by PIV-3 antigen in a microculture system. A semiautomatic multiple sample harvester was used to collect the lymphocytes from the microplates. Ultraviolet-killed PIV-3 induced better stimulation values than formalin or heat-treated virus. The highest stimulation values were obtained after a stimulation time of three to five days.