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Direct activation of human B lymphocytes by Candida albicans-derived mannan antigen

M Mangeney1, A Fischer, F Le Deist

  • 1U 132 INSERM, Hôpital des Enfants-Malades, Paris, France.

Cellular Immunology
|September 1, 1989
PubMed

Insights

This study shows that mannan, a yeast-derived carbohydrate antigen, directly activates human B cells, leading to increased cell size and RNA synthesis. This activation is specific and can initiate antibody production without T-cell help.

Area of Science:

  • Immunology
  • Cell Biology

Background:

  • B cells are crucial for adaptive immunity, recognizing antigens to initiate antibody production.
  • Mannan, a carbohydrate antigen from Candida albicans, possesses a unique polymannose branched structure.
  • Understanding B cell activation pathways is key to developing immunotherapies.

Purpose of the Study:

  • To investigate the direct activation of human resting B cells by the mannan antigen.
  • To determine the specificity and requirements for B cell proliferation upon mannan stimulation.

Main Methods:

  • Purification of dense G0 B lymphocytes from human tonsils.
  • Stimulation of B cells with purified mannan antigen.
  • Assessment of B cell activation markers (cell volume, RNA synthesis) and proliferation.
  • Evaluation of responses in B cells from mannan-sensitized versus unsensitized subjects.

Main Results:

  • Mannan antigen directly triggered B cell activation, evidenced by increased cell volume and RNA synthesis.
  • B cell proliferation was induced by recombinant interleukin 2, but not by interleukin 4 or BCGF.
  • B cell activation was mannan-specific, observed only in cells from sensitized individuals.

Conclusions:

  • Mannan can directly activate specific dense B lymphocytes.
  • This direct activation pathway may explain previous observations of T-cell independent in vitro anti-mannan antibody production.

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