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R L Guyer

Publications and source records attributed to R L Guyer.

8 recordsLinked to original sources
PubMed1979

Complement fixation by model immune complexes free in solution and bound onto cell surfaces.

Immunoglobin (IgG) molecules with anti-2,4-dinitrophenyl activity were covalently cross-linked by using three cross-linking reagents. The resulting oligomers were separated into monomer, dimer, trimer, and heavy fractions. These stable assemblages of IgG molecules were capable of fixing dilute whole guinea pig complement in solution. When oligomers were further aggregated noncovalently into larger complexes, all were able to fix complement. Radioiodinated oligomers were attached to 2,4,6,-trinitrophenylsulfonic acid treated sheep red blood cells (N3ph-SRBC), and the number of bound molecules was determined from the cell-associated radioactivity. Complement-mediated lysis of N3ph-SRBC was then assayed over a range of levels of bound protein and at increasing concentrations of complement. The lytic efficiencies of all oligomers increased with the number of bound molecules, with complement concentration, with hapten density on N3ph-SRBC, and with oligomer size. The results suggest that two adjacent IgG molecules may not serve as a unit signal for triggering the complement cascade, but instead, initiation occurs with increasing efficiency as the size of cell-bound IgG clusters increases.

Animals↗
PubMed1976

Immunoglobulin binding by mouse intestinal epithelial cell receptors.

The IgG receptors involved in transporting maternal antibodies to the blood stream of the young mouse were studied by feeding internally labeled mouse myeloma proteins and enzymatically generated specific fragments of these proteins. The data obtained from competition experiments showed the following: 1) intestinal receptors have a single specificity which is directed against IgG Fc determinants; 2) IgG subclass proteins differ in their affinities for the receptors and thus have similar but not identical Fc recognition sites; 3) the order of affinities of the IgG subclass proteins for the receptors correlates with the relative concentrations of the four subclass proteins in mouse milk; and 4) several subfractions of the Fc fragment were inactive in binding to the receptors. In many of their properties the intestinal receptors resemble the Fc receptors on other cell types, but they are apparently unique in their ability to bind tightly non-aggregated IgG molecules.

Absorption↗