Evaluation of Cryptococcus neoformans galactoxylomannan-protein conjugate as vaccine candidate against murine cryptococcosis

Siu Kei Chow, Arturo Casadevall

Research output: Contribution to journalArticle

Abstract

Galactoxylomannan (GalXM) is a complex polysaccharide produced by the human pathogenic fungus Cryptococcus neoformans that mediates profound immunological derangements in murine models. GalXM is essentially non-immunogenic and produces immune paralysis in mice. Previous studies have attempted to enhance immunogenicity by conjugating GalXM to a protein carrier, but only transient antibody responses were elicited. Here we report the generation of two GalXM conjugates with bovine serum albumin (BSA) and protective antigen (PA) of Bacillus anthracis, respectively, using 1-cyano-4-dimethylaminopyridinium tetrafluoroborate (CDAP) as the cyanylating reagent. Both conjugates induced potent and sustained antibody responses as detected by both cross antigen-based and CovaLink direct ELISAs. We confirmed the specificity of the response to GalXM by inhibition ELISA and immunofluorescence. The isotype composition analysis revealed that IgG and IgM were abundant in the immune sera against GalXM, consistent with the induction of a T cell-dependent response. IgG1 was the predominant IgG subclass against GalXM, while immunization with Quil A as adjuvant elicited a significantly higher production of IgG2a than with Freund's adjuvant. Immune sera were not opsonic for C. neoformans and there was no survival difference between immune and non-immune mice challenged with C. neoformans. These results demonstrated the effectiveness of the GalXM-protein conjugate to induce robust immune responses although no evidence was obtained that such responses contributed to host defense.

Original languageEnglish (US)
Pages (from-to)1891-1898
Number of pages8
JournalVaccine
Volume29
Issue number10
DOIs
StatePublished - Feb 24 2011
Externally publishedYes

Fingerprint

Cryptococcosis
Conjugate Vaccines
Cryptococcus neoformans
vaccines
animal pathogenic fungi
adjuvants
antiserum
mice
immune response
enzyme-linked immunosorbent assay
antigens
Bacillus anthracis
Proteins
antibodies
proteins
transport proteins
paralysis
bovine serum albumin
fluorescent antibody technique
Immunoglobulin G

Keywords

  • Capsule
  • Cryptococcus neoformans
  • ELISA
  • Galactoxylomannan
  • Immunoglobin
  • Polysaccharide

ASJC Scopus subject areas

  • Immunology and Microbiology(all)
  • Infectious Diseases
  • Public Health, Environmental and Occupational Health
  • veterinary(all)
  • Molecular Medicine

Cite this

Evaluation of Cryptococcus neoformans galactoxylomannan-protein conjugate as vaccine candidate against murine cryptococcosis. / Chow, Siu Kei; Casadevall, Arturo.

In: Vaccine, Vol. 29, No. 10, 24.02.2011, p. 1891-1898.

Research output: Contribution to journalArticle

@article{226924995ac94bcdaabb6c24e766d52f,
title = "Evaluation of Cryptococcus neoformans galactoxylomannan-protein conjugate as vaccine candidate against murine cryptococcosis",
abstract = "Galactoxylomannan (GalXM) is a complex polysaccharide produced by the human pathogenic fungus Cryptococcus neoformans that mediates profound immunological derangements in murine models. GalXM is essentially non-immunogenic and produces immune paralysis in mice. Previous studies have attempted to enhance immunogenicity by conjugating GalXM to a protein carrier, but only transient antibody responses were elicited. Here we report the generation of two GalXM conjugates with bovine serum albumin (BSA) and protective antigen (PA) of Bacillus anthracis, respectively, using 1-cyano-4-dimethylaminopyridinium tetrafluoroborate (CDAP) as the cyanylating reagent. Both conjugates induced potent and sustained antibody responses as detected by both cross antigen-based and CovaLink direct ELISAs. We confirmed the specificity of the response to GalXM by inhibition ELISA and immunofluorescence. The isotype composition analysis revealed that IgG and IgM were abundant in the immune sera against GalXM, consistent with the induction of a T cell-dependent response. IgG1 was the predominant IgG subclass against GalXM, while immunization with Quil A as adjuvant elicited a significantly higher production of IgG2a than with Freund's adjuvant. Immune sera were not opsonic for C. neoformans and there was no survival difference between immune and non-immune mice challenged with C. neoformans. These results demonstrated the effectiveness of the GalXM-protein conjugate to induce robust immune responses although no evidence was obtained that such responses contributed to host defense.",
keywords = "Capsule, Cryptococcus neoformans, ELISA, Galactoxylomannan, Immunoglobin, Polysaccharide",
author = "Chow, {Siu Kei} and Arturo Casadevall",
year = "2011",
month = "2",
day = "24",
doi = "10.1016/j.vaccine.2010.12.134",
language = "English (US)",
volume = "29",
pages = "1891--1898",
journal = "Vaccine",
issn = "0264-410X",
publisher = "Elsevier BV",
number = "10",

}

TY - JOUR

T1 - Evaluation of Cryptococcus neoformans galactoxylomannan-protein conjugate as vaccine candidate against murine cryptococcosis

AU - Chow, Siu Kei

AU - Casadevall, Arturo

PY - 2011/2/24

Y1 - 2011/2/24

N2 - Galactoxylomannan (GalXM) is a complex polysaccharide produced by the human pathogenic fungus Cryptococcus neoformans that mediates profound immunological derangements in murine models. GalXM is essentially non-immunogenic and produces immune paralysis in mice. Previous studies have attempted to enhance immunogenicity by conjugating GalXM to a protein carrier, but only transient antibody responses were elicited. Here we report the generation of two GalXM conjugates with bovine serum albumin (BSA) and protective antigen (PA) of Bacillus anthracis, respectively, using 1-cyano-4-dimethylaminopyridinium tetrafluoroborate (CDAP) as the cyanylating reagent. Both conjugates induced potent and sustained antibody responses as detected by both cross antigen-based and CovaLink direct ELISAs. We confirmed the specificity of the response to GalXM by inhibition ELISA and immunofluorescence. The isotype composition analysis revealed that IgG and IgM were abundant in the immune sera against GalXM, consistent with the induction of a T cell-dependent response. IgG1 was the predominant IgG subclass against GalXM, while immunization with Quil A as adjuvant elicited a significantly higher production of IgG2a than with Freund's adjuvant. Immune sera were not opsonic for C. neoformans and there was no survival difference between immune and non-immune mice challenged with C. neoformans. These results demonstrated the effectiveness of the GalXM-protein conjugate to induce robust immune responses although no evidence was obtained that such responses contributed to host defense.

AB - Galactoxylomannan (GalXM) is a complex polysaccharide produced by the human pathogenic fungus Cryptococcus neoformans that mediates profound immunological derangements in murine models. GalXM is essentially non-immunogenic and produces immune paralysis in mice. Previous studies have attempted to enhance immunogenicity by conjugating GalXM to a protein carrier, but only transient antibody responses were elicited. Here we report the generation of two GalXM conjugates with bovine serum albumin (BSA) and protective antigen (PA) of Bacillus anthracis, respectively, using 1-cyano-4-dimethylaminopyridinium tetrafluoroborate (CDAP) as the cyanylating reagent. Both conjugates induced potent and sustained antibody responses as detected by both cross antigen-based and CovaLink direct ELISAs. We confirmed the specificity of the response to GalXM by inhibition ELISA and immunofluorescence. The isotype composition analysis revealed that IgG and IgM were abundant in the immune sera against GalXM, consistent with the induction of a T cell-dependent response. IgG1 was the predominant IgG subclass against GalXM, while immunization with Quil A as adjuvant elicited a significantly higher production of IgG2a than with Freund's adjuvant. Immune sera were not opsonic for C. neoformans and there was no survival difference between immune and non-immune mice challenged with C. neoformans. These results demonstrated the effectiveness of the GalXM-protein conjugate to induce robust immune responses although no evidence was obtained that such responses contributed to host defense.

KW - Capsule

KW - Cryptococcus neoformans

KW - ELISA

KW - Galactoxylomannan

KW - Immunoglobin

KW - Polysaccharide

UR - http://www.scopus.com/inward/record.url?scp=79951726019&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=79951726019&partnerID=8YFLogxK

U2 - 10.1016/j.vaccine.2010.12.134

DO - 10.1016/j.vaccine.2010.12.134

M3 - Article

VL - 29

SP - 1891

EP - 1898

JO - Vaccine

JF - Vaccine

SN - 0264-410X

IS - 10

ER -