Cryptococcosisis is an infectious disease caused by yeasts from the gender Cryptococcus, being C.
neoformans and C. gattii the species more offenly isolated. Cryptococcus neoformans is a
cosmopolitan environmental pathogen of major concern among HIV patients which has a significant
incidence in developing areas. Cryptococcus neoformans blastoconidia or desiccated spores are
inhaled and can cause pneumonia and meningitis in immunosuppressed individuals. Its sibling
species, Cryptococcus gattii, is more restricted to tropical areas and infects principally
immunocompetent individuals and causes mainly pneumonia. Cryptococcus interaction with the
host has been widely studied for its capacity to modulate the immune response, replicate within
macrophages, disseminate from the lungs to the central nervous system, and/or stay in a latent
state for years. The main cryptococcal virulence factors are a polysaccharide capsule and melanin
accumulation, although this yeast has also other traits, such as urease and phospholipases that
confer adaptation to the host.
Morphogenesis is a common feature among fungal pathogens. Cryptococcus neoformans does not
form filaments nor pseudohyphae. However, during infection, this yeast undergoes cellular changes
which result in the appearance of different cellular types. These changes are: 1) Capsule
enlargement; and 2) Significant growth of the whole cell, which leads to the formation of
“Giant/Titan” cells. However, the molecular mechanisms involved in the regulation of these
processes are not known..