Molecular characterization of a mannoprotein with homology to chitin deacetylases that stimulates T cell responses to Cryptococcus neoformans

Proc Natl Acad Sci U S A. 2001 Aug 28;98(18):10422-7. doi: 10.1073/pnas.181331398. Epub 2001 Aug 14.


The fungus Cryptococcus neoformans is a major cause of morbidity and mortality in patients with impaired CD4(+) T cell function, particularly those with AIDS. To identify cryptococcal antigens that could serve as vaccine candidates by stimulating T cell responses, C. neoformans-reactive CD4(+) T cell hybridomas were generated by immunization of C57BL/6 mice and fusion of splenocytes with thymoma cells. The antigen that stimulated one of the hybridomas, designated P1D6, to produce IL-2 was purified to homogeneity by sequential anion exchange chromatography, hydrophobic interaction chromatography, and SDS/PAGE. Based on its apparent molecular mass of 98 kDa and mannosylation, the antigen of interest was named MP98. MP98 was N terminal-sequenced, and the gene encoding the protein was cloned and sequenced. Recombinant MP98, expressed in Saccharomyces cerevisiae, stimulated P1D6 to produce IL-2. Analysis of the derived 458-aa sequence of MP98 reveals an N-terminal cleavable signal sequence, a polysaccharide deacetylase domain found in fungal chitin deacetylases, and a serine/threonine-rich C-terminal region. Overall, there were 103 serine/threonine residues serving as potential O-linked glycosylation sites as well as 12 possible N-linked glycosylation sites. Thus, a C. neoformans mannoprotein has been characterized that stimulates T cell responses and has molecular properties of a chitin deacetylase.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amidohydrolases / chemistry
  • Amidohydrolases / genetics
  • Amidohydrolases / immunology*
  • Amino Acid Sequence
  • Animals
  • Antigens, Fungal / chemistry
  • Antigens, Fungal / genetics
  • Base Sequence
  • Cloning, Molecular
  • Cryptococcosis / immunology
  • Cryptococcus neoformans / enzymology*
  • Cryptococcus neoformans / genetics
  • Cryptococcus neoformans / immunology*
  • DNA Primers / genetics
  • Fungal Proteins / chemistry
  • Fungal Proteins / genetics
  • Fungal Proteins / immunology*
  • Fungal Vaccines / isolation & purification
  • Hybridomas / immunology
  • Male
  • Membrane Glycoproteins / chemistry
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / immunology*
  • Mice
  • Mice, Inbred C57BL
  • Molecular Sequence Data
  • Molecular Weight
  • Sequence Homology, Amino Acid
  • T-Lymphocytes / immunology*


  • Antigens, Fungal
  • DNA Primers
  • Fungal Proteins
  • Fungal Vaccines
  • Membrane Glycoproteins
  • mannoproteins
  • Amidohydrolases
  • chitin deacetylase

Associated data

  • GENBANK/AF361369