Open AccessC3d receptors are expressed on human monocytes after in vitro cultivation.
Author(s) -
Shinichi Inada,
Eric J. Brown,
Thelma A. Gaither,
Carl H. Hammer,
Tsuneo Takahashi,
Michael M. Frank
Publication year - 1983
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.80.8.2351
Subject(s) - trypsinization , receptor , complement factor i , microbiology and biotechnology , biology , rosette (schizont appearance) , antibody , complement system , complement receptor , incubation , in vitro , bovine serum albumin , complement factor b , trypsin , monocyte , biochemistry , immunology , enzyme
Highly purified human third component of complement (C3) was used to coat sheep erythrocytes (E) that were sensitized with IgM antibody (EA), forming EAC3b over a wide range of C3 molecules per cell. EAC3b were converted to EAC3bi by incubation with purified C3b inactivator (factor I) and beta 1H globulin (factor H). EAC3bi were in turn trypsinized to produce the cellular intermediate EAC3d. Each of the cell types was carefully characterized to be certain of the type of C3 determinant expressed. These cellular complement intermediates were used to assess by rosette formation the C3 receptor activity on peripheral blood monocytes under various experimental conditions. Uncultivated monocytes from peripheral blood bound EAC3b and EAC3bi well but did not bind EAC3d significantly. However, upon cultivation on glass surfaces in the presence of fetal calf serum but not bovine serum albumin, monocytes showed a progressive increase in expression of the C3d receptor. The Fab' fragment of anti-C3c blocked binding of EAC3b completely, blocked EAC3bi partially, but failed to block binding of EAC3d to cultivated monocytes. In contrast, the Fab' fragment of anti-C3d blocked EAC3d rosette formation completely. These studies demonstrate that monocytes are capable of expressing receptor activity for a determinant on C3d but that the expression of this receptor depends on the state of activation or differentiation of the cells.