Production and characterization of a murine monoclonal IgM antibody to human C1q receptor (C1qR)

Journal Article · Tue Jul 15 04:00:00 EDT 1986 · J. Immunol.; (United States)

OSTI ID:5459240

Ghebrehiwet, B

A hybridoma cell line that produces a monoclonal antibody (MAb) to cell surface C1q receptor (C1qr) has been produced by fusion of the P3 x 63-Ag8.653 mouse myeloma cell line with the spleen cells of a CD-1 mouse that had been hyperimmunized with viable Raji cell suspensions (5 x 10/sup 7/ cells/inoculum). This MAb, designated II1/D1, is an IgM antibody with lambda-light chain specificity. Radiolabeled or unlabeled, highly purified II1/D1 was used to determine that: a) this antibody competes for C1q binding sites on C1qR-bearing cells; b) the molecule recognized by this MAb is the C1qR; and c) cells that are known to bind C1q also bind II1/D1 in a specific manner. Western blot analysis of solubilized Raji, or U937 cell membranes, showed that the /sup 125/I-MAb detected a major protein band of approximately 85000 m.w. in its unreduced state, indicating that the C1qR is similar, if not identical, in both types of cells. Analyses of /sup 125/I-II/D1 binding experiments revealed that the antibody bound to Raji cells or u937 cells in a specific manner. Uptake of the antibody was saturable, with equilibrium virtually attained within 35 min. Scatchard analysis of the binding data using the intact MAb suggests that the affinity constant K/sub D/ is 2.9 x 10/sup -10/ M, and at apparent saturation, 24.6 ng of the antibody were bound per 2 x 10/sup 6/ cells, giving an estimated 7.8 x 10/sup 3/ antibody molecules bound per cell. That the II1/D1 antibody is specifically directed to the C1q was further evidenced by an ELISA in which the ability of C1qR-bearing cells to bind the MAb was abrogated by c-C1q in a specific dose-dependent manner.

• Research Organization: State Univ. of New York, Stony Brook
• OSTI ID: 5459240
• Journal Information: J. Immunol.; (United States), Journal Name: J. Immunol.; (United States) Vol. 137:2; ISSN JOIMA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AFFINITY
ANIMAL CELLS
ANIMALS
ANTIBODIES
ANTIGEN-ANTIBODY REACTIONS
BETA DECAY RADIOISOTOPES
DAYS LIVING RADIOISOTOPES
DOSE-RESPONSE RELATIONSHIPS
ELECTRON CAPTURE RADIOISOTOPES
ENZYME IMMUNOASSAY
GLOBULINS
HYBRIDOMAS
IMMUNOASSAY
IMMUNOGLOBULINS
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
MAN
MEMBRANE PROTEINS
MICE
MOLECULAR STRUCTURE
MONOCLONAL ANTIBODIES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PRIMATES
PROTEINS
RADIOISOTOPES
RECEPTORS
RODENTS
SOMATIC CELLS
SPLEEN CELLS
TRACER TECHNIQUES
VERTEBRATES