title: Monoclonal IgM antibody exhibiting high-affinity binding and cryoglobulin properties.
abstract: A monoclonal IgM antibody (18-2-3) derived from cell fusion of (NZB X NZW) F1 splenocytes following secondary immunization with fluorescein-conjugated keyhole limpet hemocyanin was shown to exhibit high intrinsic binding affinity and cryoinsolubility. Affinity-purified preparations were determined to be IgM by immunochemical, electrophoretic, and chromatographic analyses. An intrinsic association constant (Ka) of 2.9 X 10(10) M-1 (at 2 degrees C) was measured by first-order dissociation-rate analysis. Antibody solubility at low concentration (approximately equal to 50 micrograms/ml) was shown, by absorption spectroscopy, to be temperature dependent between 4 degrees C and 32 degrees C. Insolubility at low temperature (4 degrees C) was reversible in the presence of homologous fluorescyl hapten, indicative of active site involvement in the mechanism of cryoglobulin-18-2-3 complex formation. Characteristics of clone 18-2-3 are discussed in terms of (i) its potential use as a model for examining the mechanism of cryoprecipitation and (ii) the proposed relationship between affinity maturation and the IgM to IgG class switch.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000302:isolation & purification*; D002460:Cell Line; D002846:Chromatography, Affinity; D003450:Cryoglobulins; D005455:Fluorescent Antibody Technique; D006825:Hybridomas / Q000276:immunology; D007075:Immunoglobulin M / Q000302:isolation & purification*; D007700:Kinetics; D008214:Lymphocytes / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D010954:Plasmacytoma / Q000276:immunology; D011485:Protein Binding
chemical_list: D000911:Antibodies, Monoclonal; D003450:Cryoglobulins; D007075:Immunoglobulin M