MedCa Lab Assistant Practice Test

Cryptococcus neoformans is known for its distinctive large capsule, which plays a crucial role in its virulence. This encapsulated yeast is particularly notable for its thick, protective capsule that surrounds the cell body. The capsule is made of a complex polysaccharide known as cryptococcal polysaccharide (CPS), which not only protects the fungus from the host's immune system but also aids in its ability to cause disease, especially in immunocompromised individuals.

This large capsule serves several functions. It inhibits phagocytosis by immune cells, allowing the organism to evade the host's immune response. Additionally, it can assist in the dissemination of the fungus throughout the body, especially to the central nervous system, where it can cause serious infections such as meningitis. The size and structure of this capsule are key identifiers used in laboratory diagnosis to differentiate Cryptococcus neoformans from other fungi.

The other options, while significant in their own right, do not possess the characteristic large capsule. For example, Candida albicans typically forms pseudohyphae and yeast cells but lacks the distinctive large capsule. Aspergillus niger is primarily filamentous and does not have a capsule, and Penicillium chrysogenum, while famous for its