Cell Division Cycles of Equine Lymphocytes Cultured In Vitro

Cell division cycles of equine lymphocytes were studied in in vitro cultures of blood samples from seven horses. The first peak of the mitotic index was observed at 36-42 hr after incubation, and the population of mitotic cells at the time consisted of many at the first (97-62%) and the others at the second (3-38%) division. The frequency of cells at the second division increased gradually and reached a peak at 48 hr (62%) after incubation. The third division started at 48 hr after incubation and frequency reached 55% at 60 hr and 80% or more at 72 hr.