OPTIMAL CONDITIONS FOR MEASUREMENT OF BLASTOGENIC RESPONSES OF CHICKENS TO CONCANAVALIN-A IN WHOLE-BLOOD ASSAYS

One-day-old chicks (Cobb 500) were raised in wire cages in clean isola ted conditions and fed on a non-medicated diet. Heparinised peripheral blood samples were taken from the cutanea ulnaris (wing) vein. The ef fect of various parameters including concentration of concanavalin A ( Con A), dilution of blood in medium, volume of blood dilution per cult ure, type of media, percentage of serum, incubation period, concentrat ion of thymidine, pulse-labelling period, and age of chickens on the b lastogenic response of chickens to Con A was evaluated. The results sh owed that despite a certain degree of individual variation among respo nses, the highest response was to 0.4 mu g Con A per culture at a bloo d dilution of 1/50 in serum-free RPMI 1640 during incubation for 90 h at 40 degrees C in a humidified atmosphere containing 5% CO2. Cultures were pulsed with 0.2 mu Ci thymidine per culture for 18 h prior to ha rvesting. The stimulation response of chicken whole blood lymphocytes of chickens to Con A was prominent from 3 weeks of age onwards and the response measured in chickens 3 weeks of age was slightly higher than that of subsequent weeks. The possible applications of this technique in studying the pathogenesis of avian diseases and for quantitative a ssessment of circulating T cells of chickens are discussed.