Nonspecific immunosuppression induced in mice with killed Pasteurella haemolytica in Freund's complete adjuvant

Killed Pasteurella haemolytica type I in combination with Freund's complete adjuvant, induced suppression of murine primary response to SRBC. The suppression could be adoptively transferred with spleen cells depleted of T or B lymphocytes and was best expressed when viable cells were transferred. Some normal rabbit serum has the ability to nullify immunosuppressive effects of the transferred cells.