Mannose binding protein (MBP) enhances mononuclear phagocyte function via a receptor that contains the 126,000 M(r) component of the C1q receptor

Immunity. 1995 Oct;3(4):485-93. doi: 10.1016/1074-7613(95)90177-9.


Mannose-binding protein (MBP), C1q, the recognition component of the classical complement pathway, and pulmonary surfactant protein A (SP-A) are members of a family of molecules containing a collagen-like sequence contiguous with a noncollagen-like sequence, and usually having the properties of a lectin. C1q and SP-A have been shown to enhance monocyte FcR- and CR1-mediated phagocytosis, suggesting that the common structural features of the collagen-like domains may provide a basis for this immunologically important function. Results presented here demonstrate that MBP also enhanced FcR-mediated phagocytosis by both monocytes and macrophages, and stimulated CR1-mediated phagocytosis in human culture-derived macrophages and in phorbol ester-activated monocytes. Furthermore, a monoclonal antibody that recognizes a 126,000 M(r) cell surface protein and inhibits C1q-enhanced phagocytosis, inhibited the MBP-mediated enhancement of phagocytosis. Thus, the receptors that mediate the enhancement of phagocytosis by MBP and C1q share at least one critical functional component, the 126,000 M(r) ClqRP.

Publication types

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

MeSH terms

  • Carrier Proteins / metabolism*
  • Cells, Cultured
  • Complement C1q / metabolism
  • Humans
  • Macrophages / immunology*
  • Macrophages / metabolism
  • Mannose-Binding Lectins
  • Monocytes / immunology*
  • Monocytes / metabolism
  • Phagocytosis
  • Receptors, Cell Surface / immunology
  • Receptors, Cell Surface / metabolism*
  • Signal Transduction


  • Carrier Proteins
  • Mannose-Binding Lectins
  • Receptors, Cell Surface
  • Complement C1q