Polyclonal activation of canine B lymphocytes evaluated by a protein A reverse hemolytic plaque assay

This paper describes the optimal culture and assay conditions for the polyclonal activation of canine lymphocytes with pokeweed mitogen and the quantitation of immunoglobulin secreting plaque-forming cells (PFC) using a staphylococcal protein A-reverse hemolytic plaque assay. The assay permits the quantitation of total immunoglobulin secreting PFC as well as class-specific immunoglobulin secreting PFC. On the optimal day of culture, a mean of 176 IgA PFC/10(6), 575 IgM PFC/10(6), 1276 IgG PFC/10(6), and 2158 total PFC/10(6) cells were generated following polyclonal activation. This study provides a simple and reproducible assay for the delineation of the immunoregulatory mechanisms involved in the differentiation of canine B lymphocytes.