Immunosuppressive effects of macrophage antiserum.

Heterologous anti-macrophage serum (MAS) specifically destroys or damages macrophages in vitro. The treatment of mice by MAS results in various immunosuppressive effects: the latter are studied using phage ΦX174 and two pathogenic viruses (EMC virus and Yellow fever virus). It is shown that these effects depend both on the infectious capacity and on the dose of the particulate antigens injected. In the case of phage, MAS greatly inhibits the secondary response obtained by performing the antigenic challenge after a primary stimulation which is itself too weak for producing antibodies. In the case of the pathogenic viruses, the effects of MAS depend on whether the treatment was carried out before or after the intraperitoneal injection of virus. The implications of these results for studying the primary and the secondary responses are discussed.