Inhibition of Staphylococcal protein A precipitation of heat-aggregated IgG(AIgG) by Clq monomers

Conference · Tue Mar 04 23:00:00 EST 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:7092652

Sloand, J; Mehta, R; Knutson, D; Rosenfeld, S

Staphylococcal cells containing protein A are used to detect soluble immune complexes (ICX's). This precipitation of ICX's is dependent on the interaction of protein A with the Fc tail of the IgG molecule. Complement has been demonstrated to alter the physicochemical and biological properties of ICX's both in vivo and in vitro. They studied the effect of incorporation of radiolabelled human Clq (Clq/sup 131/I) into soluble heat aggregates of human IgG (AIgG/sup 125/I, MW = 10/sup 7/) on the subsequent ability of Staphylococcal cells to precipitate the labelled complexes. Clq was shown to be hemolytically active in preliminary red cell binding and hemolytic studies, and purity demonstrated by SDS-PAGE. Clq was incorporated by reacting AIgG 5 ..mu..g with Clq in varying amounts (.2-3 ..mu..g) for 25 min at 30/sup 0/C at normal ionic strength. S. aureus cells containing protein A (7 mg) precipitated up to 94% of AIgG/sup 125/I in the absence of Clq, and up to 10% of Clq/sup 131/I alone. Clq reduced the amount of AIgG/sup 125/I precipitated by S. aureus by 10% to 66% depending upon the dose of Clq. In conclusion, Clq, which binds at the C/sub H/2 domain, inhibits the precipitation of model ICX's by protein A, probably because of competitive binding known to be at the C/sub H/2-3 domains of the Fc portion of IgG. This could explain the inability to detect ICX's in the blood of certain patients with autoimmune diseases using this method.

• Research Organization: Univ. of Rochester, NY
• OSTI ID: 7092652
• Report Number(s): CONF-8604222-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 45:4; ISSN FEPRA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
550901 -- Pathology-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
BACTERIA
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
COMPLEMENT
CPB
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ELECTROPHORESIS
ERYTHROCYTES
GLOBULINS
IMMUNOGLOBULINS
INHIBITION
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE 131
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MATERIALS
MICROORGANISMS
MOLECULAR BIOLOGY
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PRECIPITATION
PROTEINS
RADIOISOTOPES
REACTION KINETICS
SEPARATION PROCESSES
STAPHYLOCOCCUS
TRACER TECHNIQUES