GXM blocks binding of IgG found in normal human serum to the cryptococcal cell wall.
Complement activation differs between capsulated and acapsular strain.
Thus, the cryptococcal capsule downregulates multiple arms of the host immune response in that it is antiphagocytic, prevents the initiation of the classical complement pathway, blocks inflammatory cell recruitment, diminishes Ag presentation in response to infection, suppresses the development of DTH and may reduce Ab production in response to infection. Further, in patients with AIDS, cryptococcal polysaccharide may enhance HIV replication. Figure 1 . Summary of immunomodulatory effects of cryptococcal capsular polysaccharide.