B/T cell ratio of rabbit peripheral blood lymphocytes. Influence of separation technique on results.

Spontaneous in vitro T cell rosette formation at room temperature leading to enrichment of B cells has been reported. We tested 10 individual New Zealand White rabbits sequentially, separating the lymphocytes either at room temperature or at 37 degrees C. T cells are lost constantly at room temperature but to a lesser extent at 37 degrees C. The determination of the yield of lymphocytes after Ficoll separation gives the best control for the accuracy of the results. If lymphocytes are separated at 37 degrees C and if the yield of lymphocytes is greater than 45%, the variation in T cells is small and their number is constant between 62 and 74%. These data show that the reported wide range of T cells in rabbit peripheral blood is due to methodological errors and not inherent in the rabbit.