In vitro studies on the role of the macrophages of resistant and susceptible chickens with Marek's disease

Macrophages, from susceptible S- and resistant K-strain White Leghorn chickens, were studied in vitro to determine their contribution to the dynamics of Marek's disease (MD) and possible role in genetic resistance to this disease. In relation to basic macrophage properties (morphology, cell spreading, enzyme levels, pinocytosis, and phagocytosis) there were no significant differences between S- and K-strain macrophages. Both macrophage strains were observed to respond to JM virus by phagocytic responses, but no viral replication or transference of infectivity was observed within inoculated macrophage cultures. In general, there were no differences between S- and K-strain macrophages in vitro that may account for the genetic resistance or susceptibility to MD.