CHITINASE LEVELS IN GUINEA-PIG BLOOD ARE INCREASED AFTER SYSTEMIC INFECTION WITH ASPERGILLUS-FUMIGATUS

The presence of chitinase activity in human serum has recently been de scribed by us. On that occasion we speculated on the possible role of mammalian chitinases as a defense mechanism against chitin-containing pathogens. The results of the present study substantiate our hypothesi s, We demonstrate and partially characterize the chitinase activities that are present in plasma of guinea pigs and in homogenates of A.fumi gatus with the aid of the substrates MU-[GlcNAc](2,3) and also with gl ycol [H-3]chitin. Upon infection with A. firmigatus the serum chitinas e activity levels in the circulation of pathogen-free guinea pigs incr eased in a time-dependent manner. The increase was also dependent on t he size of the infecting fungal inoculum, Antifungal treatment diminis hed the increases, The increased chitinase activity was of guinea pig origin. The activity of beta-hexosaminidase showed a very slight incre ase subsequent to the infection, The activities of three other enzymes of lysosomal origin (alpha-mannosidase, beta-galactosidase and beta-g lucosidase) did not increase.