Blastogenic response of whole blood cells of turkeys to a T-cell mitogen

Cellular immune mechanisms in the turkey are not well understood because adequately standardized, reproducible in vitro assays to measure cellular immunity are not available. Our purpose was to optimize conditions for a whole blood mitogenic assay that would facilitate quantitative assessment of the ability of circulating T cells of turkeys to respond to Con A. Heparinized peripheral blood from normal turkeys was examined. Data indicated that diluting the blood 1:20 or 1:40 and incubating the test cultures at 39 degrees C or 41 degrees C gave the best mitogenic stimulation. Presence of 7.5% turkey serum but not chicken or fetal bovine serum in the culture medium substantially enhanced the blastogenic response. Ontogeny of the whole blood mitogenic response was examined by repeat observations on a group of turkeys at various age levels starting at 1 week of age. Whole blood cells from 1-week-old turkeys responded poorly to Con A, although by 2 weeks of age, the response was well developed. Tests at subsequent ages revealed variable levels of activity. There was a considerable individual variation in the level of blastogenic response of turkeys within the same age group.