Basophil chemotaxis under agarose: variability among guinea pig donors and response to sera of different species

Guinea pig basophils were tested against chemotactic factor(s) generated from homologous and heterologous sera. An "under agarose" method of quantitating leukocyte chemotaxis was adapted to measure serum-derived basophil chemotactic factor(s) (BCF). The method was found to be simple, reproducible, and sparing of time and reagents and it provided simultaneous controls. Because of the economy of reagents compared with the Boyden chamber technique, basophils from individual guinea pigs could be studied and were found to be variable in responsiveness. A definite difference in the response of guinea pig basophils to zymosan-activated sera of various other species was demonstrated. Guinea pig basophils responded to zymosan-activated serum from guinea pig and rat but failed to respond to zymosan-activated serum from human, hamster, rabbit, or cow. Optimal conditions were determined for cell numbers, serum activation and dilution, and migration times for studies of guinea pig BCF. The under agarose technique provides a practical alternative to chamber methods for the study of basophil chemotaxis. Although guinea pig basophils do not respond to human serum-derived BCF, the economy of reagents with this technique gives promise toward adaptation of the method to studies of human basophil chemotaxis.