PubMed Health⌕ Search

Biomedical subjects

A Langendries

Publications and source records attributed to A Langendries.

10 recordsLinked to original sources
PubMed1998

In vivo stimulation of polymeric Ig receptor transcytosis by circulating polymeric IgA in rat liver.

Binding of human polymeric IgA ligand to its epithelial cell polymeric Ig receptor, pIgR, has been shown to stimulate pIgR apical transcytosis in an in vitro system, based on polarized confluent MDCK cells expressing rabbit pIgR. The present study aimed at testing whether such a stimulation also occurs in vivo. Transcytosis of pIgR was monitored by rat liver output of total secretory component (SC) into bile, measured by radial immunodiffusion as the sum of free SC and pIgA-bound SC. Whereas in the perfused rat liver system addition of pIgA to the perfusate showed no effect, i.v. injection of human and rat pIgA, but not of monomeric IgA nor PBS, in living rats significantly increased total bile SC output for more than 1 h. Furthermore, depletion of the normal pIgA level circulating in the liver before injecting more pIgA was not required to show the stimulation. Our data thus strongly suggest that stimulation of liver pIgR transcytosis by pIgA ligand binding is physiologically relevant, helping to quickly adjust pIgA transport into bile to increase circulating pIgA levels, without need for increased SC/pIgR synthesis.

Animals↗
PubMed1998

Secretory component production by human bronchial epithelial cells is upregulated by interferon gamma.

Secretory immunoglobulin A (S-IgA) participates in the first noninflammatory line of defence of the respiratory tract. S-IgA consists of dimeric IgA (dIgA) produced by plasma cells and secretory component (SC) produced by epithelial cells. This study compared SC production by primary cultures of human bronchial epithelial cells (HBEC) and by respiratory epithelial cell lines. Among the cell lines, A549 did not produce detectable SC, 16HBE produced very low levels of SC, while CALU-3 produced significant levels of SC. HBEC produced SC in nonpolarized and polarized primary cultures, where it was secreted apically. Polarized HBEC transcytosed radiolabelled and cold dIgA, resulting in the presence of S-IgA in their apical media. SC production and IgA transcytosis by polarized HBEC were upregulated by interferon-gamma (IFN-gamma) after 48 h. By reverse transcription-polymerase chain reaction, no SC messenger ribonucleic acid (mRNA) was detected in A549 and 16HBE, while SC mRNA in CALU-3 was comparable to that of HBEC incubated for 48 h with IFN-gamma. By immunocytochemistry, HBEC expressed SC immunostaining and its intensity increased after 48 h with IFN-gamma. It is concluded that human bronchial epithelial cells produce secretory component and transcytose dimeric immunoglobulin A in vitro. These processes were apically polarized and upregulated by interferon-gamma. Among the cell lines studied, only CALU-3 expressed secretory component-messenger ribonucleic acid and produced detectable secretory component.

Aged↗
PubMed1997

Contribution of serum IgA to intestinal lymph IgA, and vice versa, in minipigs.

Immune cells in pig gut lymph are rather well studied, but data on gut lymph immunoglobulins and their origin are nonexistent. Such data are important to understand the interplay between pig systemic and intestinal immunity as a basis for vaccination studies. In some species, gut lymph contributes much to plasma IgA, but apparently not in humans. To estimate the contributions of pig serum IgA to intestinal lymph IgA and vice versa, concentrations of IgA, IgG, IgM, albumin, haptoglobin, C3 and alpha 2-macroglobulin were measured by radial immunodiffusion in paired porcine intestinal lymph and serum samples. All proteins, except IgA, had lymph/serum ratios (< 1.0) inversely related to their size, depending on passive diffusion from serum. The mean lymph/serum ratio of IgA was 2.2 instead of an expected 0.50 or 0.65 (dimer or monomer, respectively), indicating that of the IgA in gut lymph, 22.7 or 29.5% came from serum, vs 77.3 or 70.5% from the intestine. Percentage of polymeric IgA, measured by gelfiltration and corrected radial immunodiffusion, was 64.3% in porcine mesenteric lymph and 47.3% in serum. As the pig plasma volume and daily gut lymph flow into circulation were known, it could be calculated that roughly 31% of the total plasma IgA originated daily from local intestinal synthesis, reaching blood via mesenteric lymph.

Animals↗
PubMed1997

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.

Animals↗
PubMed1995

Homogenous IgA monomers, dimers, trimers and tetramers from the same IgA myeloma serum.

Starting from two IgA1 myeloma sera, the isolation of monoclonal monomeric, dimeric, trimeric and tetrameric IgA in a high state of purity and size homogeneity for each serum is described. The method combined repetitive gel filtrations on Ultrogel AcA22 with affinity chromatography on Jacalin-Sepharose. These various forms of pure polymeric IgA obtained from the same monoclonal IgA should allow a precise comparison of their respective structure and reactivity with different IgA-binding proteins, such as IgA Fc-receptors, the polymeric Ig receptor, and lectins.

Antibodies, Monoclonal↗
PubMed1988

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.

Animals↗