EFFECTS OF INFESTATION BY RHIPICEPHALUS-SANGUINEUS ON LYMPHOCYTE BLASTOGENIC RESPONSES TO MITOGENS IN DOGS

Mitogen blastogenic responses of lymphocytes from dogs infested with a dult Rhipicephalus sanguineus and the effects of salivary gland extrac ts (SGE) of the tick on the blastogenic responses of lymphocytes from normal dogs were studied. Infestation by R. sanguineus significantly s uppressed concanavalin A, phyto-hemagglutinin and pokeweed mitogen res ponses of lymphocytes from dogs. The inhibition of lymphocyte response s of dogs in the first infestation was greater than that in the second infestation. SGE from R. sanguineus also suppressed all mitogen blast ogenic responses of lymphocytes from healthy dogs in vitro. These supp ressive effects of SGE on the blastogenic responses of PBL to mitogens were significantly inhibited by trypsin digestion. It is suggested th at some proteins in SGE contribute to the suppressive effects of SGE o n the blastogenic responses of peripheral blood lymphocytes from dogs.