Origin and molecular size of immunoglobulin-A in the mesenteric lymph of the dog.

Samples of mesenteric lymph, thoracic duct lymph or lymph of mixed (hepatic and intestinal) origin from adult dogs were compared with serum from the same animals with regard to the concentrations of different proteins, particularly IgA, IgM, IgG, IgG and IgG. In all samples the lymph to serum ratio for IgA was found considerably to exceed the corresponding ratios for the other immunoglobulins. From these data it was calculated that from 60 per cent to over 95 per cent of the IgA in mesenteric lymph was produced by the plasma cells of the intestinal mucosa, and that the latter significantly contributed to the pool of circulating IgA.

Distribution of various immunoglobulin containing cells in canine lymphoid tissue.

The spleen, lymph nodes and gastro-intestinal mucosae of the dog were investigated with respect to the size and nature of their plasma cell populations. As in all other mammals so far studied, the gastro-intestinal mucosae of the dog were conspicuous by their wealth of IgA-containing plasma cells.

Distribution of alpha-chain subclasses in normal and pathological IgA-globulins.

Of 332 monoclonal IgA-components, 6·6 per cent belonged to the subclass, and the remainder to the subclass of α-chains. The light-chain type distribution (κ or λ) was not statistically different in these two subclasses, being 54·5 and 57·7 per cent, respectively. Proteins of subclass tended to occur at higher average concentrations in the pathological sera, and were of a higher electrophoretic mobility, than were components of the type.

Subclasses of human immunoglobulin a based on differences in the alpha polypeptide chains.

Antiserum from goats immunized with heavy polypeptide chains from a gammaA-type myeloma globulin was absorbed with serum from patients with selective absence of immunoglobulin A (gammaA). The resulting reagents could be used for the classification of 58 gammaA-myeloma proteins into two distinct antigenic types, respectively called subclasses He and Le. These differences were shown to be related to the heavy (alpha) polypeptide chains and independent of the integrity of interchain disulfide bridges.