title: Anti-glucuronoxylomannan IgG1 specific antibodies production in Cryptococcus neoformans resistant mice.
abstract: BACKGROUND
  Cryptococcus neoformans is a widely disseminated fungus shown to be responsible for infections in individuals with impaired cell mediated immunity, such as patients with human immunodeficiency virus (HIV). Cryptococcus neoformans has a polysaccharide capsule composed of glucuronoxylomannan (GXM), which acts as a major virulence factor and is considered to be a thymus independent type-2 antigen (TI-2).
  
  
  OBJECTIVE
  In the current study, the production kinetics were evaluated for IgG subclasses specific for GXM, and assessed with the cross reactive antibodies to Streptococcus pneumoniae polysaccharide. In addition, spleen B cell subpopulations were quantified in murine models of cryptococcosis with different susceptibilities to the infection.
  
  
  METHODS
  Antibodies were detected by ELISA at different time intervals after C. neoformans infection in moderately resistant (Balb/c), highly resistant (CBA/j) and susceptible (C57BL/6) mouse strains. B cells subpopulations were determined by flow cytometry analysis.
  
  
  RESULTS
  Early production of IgG1, described as protector antibodies, coincided with a decrease of the number of C. neoformans colony forming units in the lungs. Polysaccharide cross-reactive antibodies were detected in each of the three mouse strains. Antibody titers were highest in the susceptible strain (C57BL/6), a strain which also showed the highest proportion of splenic CD5+ B lymphocytes. In contrast, CBA/J mice showed the highest levels of CD43+ B.
  
  
  CONCLUSIONS
  These findings suggest that IgG1 antibodies specific for GXM, are implicated in host protection against C. neoformans infection and may be regulated by CD43+ cells. They also suggest that cross reactivity antibodies are not important in the protection against C. neoformans infection.
authors.affiliation: Grupo de Inmunobiología, Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá, D.C., Colombia.
authors.forename: Claudia
authors.initials: C
authors.lastname: Parra
authors.forename: John Mario
authors.initials: JM
authors.lastname: González
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Castañeda
authors.forename: Susana
authors.initials: S
authors.lastname: Fiorentino
mesh_terms: D000818:Animals; D000908:Antibodies, Fungal / Q000097:blood*; D000946:Antigens, Fungal / Q000276:immunology; D003453:Cryptococcosis / Q000276:immunology; D003455:Cryptococcus neoformans / Q000276:immunology*; D005434:Flow Cytometry; D007074:Immunoglobulin G / Q000097:blood*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D011134:Polysaccharides / Q000276:immunology*
chemical_list: D000908:Antibodies, Fungal; D000946:Antigens, Fungal; D007074:Immunoglobulin G; D011134:Polysaccharides; C027478:glucuronoxylomannan