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Association of low levels of mannan-binding protein with a common defect of opsonisation

M Super1, S Thiel, J Lu

  • 1Department of Immunology, University of London.

Lancet (London, England)
|November 25, 1989
PubMed

Insights

A common defect in yeast opsonisation is linked to low mannan-binding protein (MBP) levels. Supplementing MBP corrected this defect, highlighting its crucial role in the immune response.

Area of Science:

  • Immunology
  • Microbiology

Background:

  • 5-7% of the population exhibits a defect in opsonising Saccharomyces cerevisiae (baker's yeast).
  • This defect is associated with reduced levels of mannan-binding protein (MBP), a calcium-dependent serum lectin.

Purpose of the Study:

  • To investigate the link between low mannan-binding protein (MBP) levels and the defect in yeast opsonisation.
  • To determine if purified MBP can correct the opsonic defect in vitro.

Main Methods:

  • An in-vitro assay was used to measure complement moiety deposition on a mannan-coated surface.
  • Serum MBP levels were measured and correlated with C3b opsonin generation in healthy blood donors.
  • MBP levels were compared between children with the opsonic defect and a paediatric control group.

Main Results:

  • Purified MBP corrected the yeast opsonisation defect in a dose-dependent manner.
  • A significant correlation was found between serum MBP levels and C3b opsonin generation.
  • Children with the opsonic defect had significantly lower median MBP levels (4.9 µg/l) compared to controls (143 µg/l).

Conclusions:

  • Low serum mannan-binding protein (MBP) levels are directly linked to the common defect in Saccharomyces cerevisiae opsonisation.
  • MBP plays a critical role in complement-mediated opsonisation and innate immunity.
  • MBP supplementation is a potential therapeutic strategy for individuals with this opsonic defect.

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