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 isolated conditions and fed on a non-medicated diet. Heparinised peripheral blood samples were taken from the cutanea ulnaris (wing) vein. The effect of various parameters including concentration of concanavalin A (Con A), dilution of blood in medium, volume of blood dilution per culture, type of media, percentage of serum, incubation period, concentration of thymidine, pulse-labelling period, and age of chickens on the blastogenic response of chickens to Con A was evaluated. The results showed that despite a certain degree of individual variation among responses, the highest response was to 0.4 μg Con A per culture at a blood dilution of 150 in serum-free RPMI 1640 during incubation for 90 h at 40°C in a humidified atmosphere containing 5% CO2. Cultures were pulsed with 0.2 μCi thymidine per culture for 18 h prior to harvesting. 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 than that of subsequent weeks. The possible applications of this technique in studying the pathogenesis of avian diseases and for quantitative assessment of circulating T cells of chickens are discussed.