Vol.62 No.6 November 2014
Immune response and immune memory to cryptococcal infection -The relationship to reactivation of this fungal pathogen
Department of Medical Microbiology, Mycology and Immunology, Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Miyagi, Japan
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen, which frequently causes fatal meningoencephalitis in AIDS patients. Host defense to this fungus is mediated by the cellular immune response, and Th1-Th2 cytokine balance plays a critical role in determining the outcome of this infection. Host cells initiate the immune response through recognition of pathogen-associated molecular patterns, in which pattern recognition receptors, such as Toll-like receptors(TLRs) and C-type lectin receptors(CLRs), are deeply involved. In cryptococcal infection, TLRs, like TLR2 and 9, and CLRs, like DC-SIGN, mannose receptor and Dectin-2, are reported to contribute to the host defense. Recently, several pieces of clinical evidence have been reported, which suggested the development of cryptococcal meningitis by reactivation of persistently infected C. neoformans in patients with impaired cell-mediated immunity. Under this condition, it would be important to understand how the reaction of the immune memory system to this fungal pathogen is developed and dysregulated, and further investigation is necessary to address these issues.
Key word
host defense, cryptococcal infection, cytokines, pattern-recognition receptors, immune memory
Received
July 28, 2014
Accepted
August 19, 2014
Jpn. J. Chemother. 62 (6): 674-680, 2014
