Immunosuppressive action in vitro by a bovine spleen extract.

Bovine spleen obtained from 1 — 2 years old animals was dissected and the capsule and fibrous tracts removed. The cells from the remaining tissue were washed 3 times with saline solution resuspended in 100 ml of distilled water and left for one hour. The suspension was then homogenized during 1 min with an Ultra-Turrax homogeneisor, left 30 min and then centrifuged at 17,000 rpm for 45 minutes. The pellet was discarded and the supernatant dialysed against deionized water for 24 hours. The precipitation produced by dialysis was eliminated by centrifugation. Ethanol (96%) was then added drop by drop to the supernatant until a 75% ethanol concentration was readied. The