Nomenclature of immunoglobulin A and other proteins of the mucosal immune system

The predominant immunoglobulin found in exocrine secretions of humans and most other mammals is secretory IgA, a polymeric form of IgA containing an additional glycoprotein chain designated "secretory component." In this article recommended abbreviations are proposed for the following forms of human IgA and other proteins of related interest: secretory IgA, secretory IgM, secretory component, polymeric immunoglobulin receptor, polymeric IgA, monomeric IgA, IgA subclass 1, IgA subclass 2, A2 allotype marker 1, and A2 allotype marker 2

Studies of IgA immunoglobulins in man and animals

Thèse d'agrégation de l'enseignement supérieur (Faculté de médecine) -- UCL, 197

Hepatobiliary transport of IgA in the golden Syrian hamster (Mesocricetus auratus)

Do hamsters, like rats, rabbits and mice, possess an hepatocyte 'IgA pump' whereby circulating plasma polymeric IgA (pIgA) is actively transported into bile, against a concentration gradient, via the polymeric Ig receptor or secretory component (SC)? Precipitating antisera, raised against rat Igs and serum proteins, and crossreacting with their hamster homologues, detected hamster SC by immunoelectrophoresis in bile, but not serum. Gel filtration of hamster bile indicated that free SC eluted between IgG and albumin, as for other mammals. Hamster bile IgA was pIgA, and was true secretory IgA (SIgA) by its reaction with anti-SC antiserum and by SDS-PAGE with reduction. Hamster serum IgA comprised both pIgA and IgA monomers. Mean bile-to-serum concentration ratios (B/S) for IgA, IgG, transferrin and albumin, measured by radial immunodiffusion, were 2.65, 0.019, 0.024, and 0.016, respectively, demonstrating strongly selective enrichment of bile in IgA. Human 125I-labelled dimeric IgA was injected into the circulation of five hamsters with cannulated bile ducts; 20% of the [125I]IgA (> 95% precipitable by trichloroacetic acid) was recovered in bile within 5 h, a figure close to that for mice, but smaller than that for rats and rabbits. The data suggest that bile significantly contributes to hamster intestinal SIgA, as shown for rats, rabbits and mice. This could be relevant to studies where hamsters are used as an experimental model for infection by the human intestinal pathogen, Clostridium difficile

Cholera toxin neutralization: a comparison of purified serum IgG and biliary secretory IgA antibodies.

Rats were immunized three times with cholera toxin via the intraintestinal or intravenous route, and their respective biliary secretory IgA (sIgA) or serum IgG antibodies were affinity-purified on a cholera toxin immunoabsorbent. On a molar basis, the sIgA antibodies were roughly seven-fold more efficient than IgG antibodies in neutralizing cholera toxin in the ligated intestinal loop assay. Various explanations for this difference in neutralizing capacity are proposed

Use of anti-cholera toxin IgA-secreting hybridoma cells for the elaboration of an antigen-specific IgA-ELISPOT-assay.

Hybridoma anti-cholera toxin (CT) IgA-secreting cells, because of their monoclonal character, were used to establish and optimize an ELISPOT-assay for CT-specific IgA-secreting cells. The use of hybridoma cells easily and quickly allowed the elaboration of a sensitive, specific and reproducible ELISPOT-assay, which was successfully applied to enumerate intestinal lamina propria lymphoid cells secreting anti-CT IgA in mice immunized twice intraintestinally with CT. Monoclonal antibody-secreting hybridoma cells, if available against a given antigen, are suggested as ideal cell suspensions to elaborate new ELISPOT-assays to study antibody responses at the cellular level