Structural requirements for incorporation of J chain into human IgM and IgA

Structural requirements for incorporation of J chain into human IgM and IgA.

J chain is associated with pentameric IgM and dimeric IgA via disulfide bonds involving the penultimate cysteine residue in the secretory tailpiece of the mu or the alpha heavy chain. We have investigated the structural basis for incorporation of J chain by analyzing several IgM mutants, IgA mutants and IgG/IgM hybrid molecules. IgM mutants with the mu secretory tailpiece replaced by the alpha ...

Chain-Deficient IgM Structural and Functional Analysis of J

some arrangement of inter-␮ bonds directs incorporation of J chain. IgM-S337 hexamer also dissociated to ␮2␬2 and ␮4␬4, but also yielded several species migrating much more slowly in SDS-PAGE than wild-type ␮12␬12. To account for these forms, we propose that each ␮-chain can interact with three other ␮-chains and that some hexameric molecules contain two catenated ␮6␬6 circles. J chain is a 15-...

Site of J chain attachment to human polymeric IgA.

A fragment containing J chain was released from human polymeric myeloma IgA protein by cyanogen bromide cleavage. The identity of the fragment was determined by its electrophoretic mobility and antigenic determinants. After purification by gel filtrations and DEAE-Sephadex chromatography, this fraction appeared similar (with respect to its amino acid and carbohydrate compositions and its peptid...

Serum IgM and IgA

SYNOPSIS Immunofluorescent serum IgM and/or a significant level of IgA antibody was detected in 87 % of 39 cases of current or recent influenza A infection from two to 84 days after the onset of illness. Secondary IgM staining occurred in 5% of sera and a significant correlation was found between complement-fixing and class-specific antibodies. It was estimated that the immunofluorescent test c...

Receptor of Human IgA with the Human Polymeric Ig Structural Requirements for the Interaction