Rev Iberoam Micol. 2014;31(1):76–80 Revista Iberoamericana de Micología www.elsevier.es/reviberoammicol Mycologic Forum Effect of Histoplasma capsulatum glucans on host innate immunity Roberto Lara-Lemus a , Noé Alvarado-Vásquez a , Edgar Zenteno b , Patricia Gorocica a,* a Departamento de Bioquímica, Instituto Nacional de Enfermedades Respiratorias, México DF, Mexico b Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, México DF, Mexico a r t i c l e i n f o Article history: Received 27 August 2013 Accepted 1 October 2013 Available online 16 November 2013 Keywords: Histoplasma capsulatum Glucans Polysaccharides Immunomodulation a b s t r a c t -1,3-Glucan is important for infective forms (mycelial phase) of Histoplasma capsulatum and shares many features allotted to pathogen-associated molecular patterns. These cell wall carbohydrates inter- act with phagocytes by binding to Toll and lectin-like receptors, present on cell surfaces of macrophages, neutrophils, and dendritic cells. This review focuses on recent findings of the major H. capsulatum and host carbohydrate-driven interactions that account for internalization of fungal infective forms into phagocytes, and its subsequent avoidance of intracellular elimination. The yeast phase of H. capsulatum possesses different modulating factors of the macrophagic-anti-fungal mechanisms, mainly -1,3-glucan, which is considered relevant for virulence. This manuscript is part of the series of works presented at the “V International Workshop: Molecular genetic approaches to the study of human pathogenic fungi” (Oaxaca, Mexico, 2012). © 2013 Revista Iberoamericana de Micología. Published by Elsevier España, S.L. All rights reserved. Efecto de los glucanos de Histoplasma capsulatum sobre la inmunidad innata del huésped Palabras clave: Histoplasma capsulatum Glucanos Polisacáridos Inmunomodulación r e s u m e n El -1,3-glucano es importante para las formas infectivas (fase micelial) de Histoplasma capsulatum y com- parte varias características asignadas a los patrones moleculares asociados con patógenos. Estos hidratos de carbono de la pared celular interaccionan con los fagocitos uniéndose a receptores tipo Toll y tipo lectina, que están presentes en las superficies celulares de macrófagos, neutrófilos y células dendríticas. En esta revisión se presta atención a los hallazgos recientes sobre las principales interacciones entre H. capsu- latum y las células del huésped mediadas por hidratos de carbono, que permiten la internalización de las formas infectivas del hongo por los fagocitos, así como la posterior evitación de su eliminación intracelu- lar. Se discuten los datos experimentales relevantes publicados recientemente. La fase de levadura de H. capsulatum incluye distintos factores moduladores de los mecanismos de macrófagos y antifúngicos, sobre todo el -1,3-glucano, que se considera relevante para la virulencia. Este artículo forma parte de una serie de estudios presentados en el «V International Workshop: Molecular genetic approaches to the study of human pathogenic fungi» (Oaxaca, México, 2012). © 2013 Revista Iberoamericana de Micología. Publicado por Elsevier España, S.L. Todos los derechos reservados. Pathogens recognition is commonly based on the identifica- tion of molecular patterns by distinct receptors and subsequent activation of signaling pathways, which allow the defense reac- tion to fend off invading microorganisms. Pathogen fungi have several molecular components in the cell wall that play a crit- ical role in their pathogenicity mechanisms. Indeed, cell wall contains adhesins and a broad number of receptors interacting * Corresponding author. E-mail addresses: gorocicap@gmail.com, pgorocica@yahoo.com.mx (P. Gorocica). with environmental factors that, after activation, start a com- plex network of downstream intracellular signals. 14 The dimorphic fungal pathogen Histoplasma capsulatum var. capsulatum causes the respiratory and systemic disease, histoplasmosis. 27 Like most systemic-disease-causing fungal pathogens, this infection is acquired via the respiratory tract by inhalation of infective propagules, mainly microconidia, hypha fragments, and spores produced during the mycelial phase of this fungus. 29,59 Target organs are lungs, where alveolar macrophages and dendritic cells (DCs) are responsible for phagocytosis of infective forms, establish- ing the link with the adaptive immune response. 13,32 Dimorphic switching from the mycelial phase (M-morphotype) to yeast phase 1130-1406/$ – see front matter © 2013 Revista Iberoamericana de Micología. Published by Elsevier España, S.L. All rights reserved. http://dx.doi.org/10.1016/j.riam.2013.10.005