Synthetic Peptides as an Alternative Tool for the Diagnosis of Cryptococcosis

Abstract

Cryptococcosis is an important systemic mycosis that threatens the lives of humans and animals. The disease is caused by two species of the genus Cryptococcus Cryptococcus neoformans and Cryptococcus gattii. The diagnosis of cryptococcosis is made through microscopy, fungal culture followed by biochemical tests, and detection of the cryptococcal capsular antigen CrAg . Despite the existence of an established diagnostic protocol, the search for new diagnostic tests is necessary due to the high incidence of the disease, with estimates of approximately million cases of cryptococcal meningitis per year and more than , deaths in patients infected with human immunodeficiency virus HIV , the potential for C. gattii to cause the disease in immunocompetent individuals, and the disease's rapid worldwide dissemination. With the development of biotechnology, synthetic peptides have opened up new possibilities as a source of pure epitopes and molecules for the diagnosis of various diseases, based on the detection of circulating antibodies. Synthetic peptides can also be used for the development of vaccines. Studies on Leishmaniasis, Chagas disease, paracoccidioidomycosis, tuberculosis, and, more recently, on cryptococcosis, among others, have shown that this approach shows potential for the early diagnosis of the disease, thus reducing the morbi-lethality of individuals affected by this infection and ultimately changing their prognosis.Keywords: Cryptococcosis, diagnosis, antigens, synthetic peptides, B cell, epitopes . IntroductionCryptococcosis is an important systemic mycosis that threatens the lives of humans and animals. It manifests primarily through respiratory system diseases and meningoencephalitis. Cryptococcosis is among the emergent fungal infections with significant morbi-lethality, and it is the fourth most frequent cause of opportunistic infection in human immunodeficiency © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.virus HIV -positive patients. The disease is caused by two species of the genus Cryptococcus Cryptococcus neoformans and Cryptococcus gattii [ , ].C. neoformans has a worldwide distribution and is responsible for the high morbi-lethality in immunocompromised individuals with AIDS. In contrast, infections with C. gattii are prevalent in tropical and subtropical climate regions, and C. gattii primarily attacks immunocompetent hosts. However, C. gattii has also emerged in countries with temperate climates, e.g., Canada Vancouver and the U.S. Northwest, which demonstrates that the fungus may adapt to new environments and cause surges of infection in animals and humans [ -].Annually, AIDS-related cryptococcal meningitis is responsible for approximately % of the mortality in these individuals [ ]. Sub-Saharan Africa has the largest rate of coinfecti...