|
Factor | Function |
|
Capsule and its associated polysaccharides | Evasion of
phagocytosis [67]
|
Reduction of antigen
presentation [68] |
Reduction of
cytokine production [69] |
Induction of
suppressor T-cells which inhibit cell-mediated immunity [70] |
Inhibition of T-cell
responses by GXM [31] |
Inhibition of leukocyte migration into inflammatory sites by GXM [31, 71] |
|
Melanin | Protection against
UV radiation [72] |
Protection against
oxygen and nitrogen free radicals [73, 74] |
May contribute to central nervous system tropism [6] |
Contributes to
negative cellular charge [75] |
|
Mannitol | Suggested increase
in intracranial pressure [76] |
Protection against
stress [77] |
Protection against
oxygen free radicals [78] |
|
Extracellular protease | Proteolytic activity
[79] |
May contribute to
degradation of proteins involved in tissue integrity and host immunity [79–82] |
|
Products of laccase pathway | Diphenol oxidation [83]
|
Synthesis of melanin
[84] |
Degradation of wood
lignin [15] |
|
Superoxide dismutase | Protection against
oxidative stress [85] |
Protection against
oxidative burst produced by immune effector cells [85] |
|
Phospholipases | Tissue invasion via
degradation of mammalian membrane lipids and lung surfactant [15, 86] |
|
Urease | Exact function is
unknown [87] |
May aid in transfer
of Cryptococcus to central nervous
system [88] |
|
STE1 transcription factor (in cells of
mating type) | Upregulation leads
to synthesis of diphenol oxidase (which is a laccase) [89, 90] |
|
Growth at physiological temperature (37) | Survival and
persistence in the host [15] |
|
Tolerance of low pH | Survival and
persistence in the environment [47] |
|
Tolerance of elevated salt | Survival and
persistence in the environment [47] |
|
Phenotypic switching | Change in capsule
size—mucoid variant more virulent, smooth variant
suggested to be able to cross blood-brain barrier [91] |
|