The Role of Late Complement Components and the Alternate Complement Pathway in Experimental Cryptococcosis

Duration of survival was comparable in normal and C4D guinea pigs infected iv with cryptococci. Survival was shortened in animals depleted of late complement components by treatment with CVF. Some animals received a single treatment with CVF to allow recovery of complement components after challenge with cryptococci. This resulted in lower counts of fungi in peripheral blood, lung, and liver, but no improvement in levels of fungi in brain, or in survival when compared with animals continuously depleted of C3–9. Late complement components were therefore important in clearance of cryptococci from extraneural sites. However, once infection was established in brain, complement levels in the central nervous system may have been too low to aid in destruction or organisms.