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PubMed1990

Immunoglobulins in Hassall's corpuscles of the human thymus.

Ninety nine human thymuses were examined immunohistochemically for the presence of immunoglobulins G, A, M. D and E, light-chains, secretory component and albumin in the cells of Hassall's corpuscles. Igs G, A, M and secretory component were present. These showed a rise after birth until the age of 20 years and also increased with the degree of involution, falling when involution became complete. Albumin was also consistently demonstrated. There was a degree of correlation between the presence of Igs and production of Igs G, A and M by plasma cells in the thymic medulla. There was a close correlation between the amounts of IgA and secretory component in the cells of Hassall's corpuscles and the thymus may have to be regarded as a part of the secretory-IgA system. Light chains of the immunoglobulin molecule were also present, with lambda predominating over kappa, possibly reflecting the same kappa/lambda ratio found with thymic immunoglobulin production. No IgD or IgE was demonstrated. The presence of albumin may represent a passive uptake of protein in senescent cells but a more active uptake of Igs, particularly IgG and IgA, could be postulated. The production of Igs in the thymus and their presence in Hassall's corpuscles could be of significance in the maturation and regulation of the immune response.

Adolescent↗
PubMed1985

Influence of glucocorticoid and betamimetic therapy on milk secretory IgA concentration produced by mothers delivering preterm infants.

A prospective study was performed to find the possible difference in secretory IgA concentration in milk of mothers with term pregnancy labors and those delivering at earlier gestational ages. Since tocolytic drugs and/or glucocorticoid agents are usually given in cases of threatened premature labor, the pre-term group was divided into mothers with or without medication. Thirty two mothers were distributed in three groups: Group I, mothers with preterm labors without any medication; Group II, preterm labors with previous treatment with betamimetics and glucocorticoids; Group III, term labors (see Tab. I). In each of the three groups, three periods were studied: colostral (4 to 5 days postpartum), transitional (8 to 10 days), and mature (14 to 15 days). All mothers were healthy, with good nutritional state, without local inflammation and membranes had been ruptured 12 hours or less before labor. There was no significant difference in the proportion of primiparas and multiparas in both groups. The gestational age was evaluated by amenorrhea and neonatal examination. In all mothers milk was extracted with a vacuum pump to empty the mammary gland. The determinations were made using a specific antibody against the secretory component. The concentration of free secretory component in these milks was practically insignificant. No differences were found in the concentration of secretory IgA among the three groups (Tab. II, Fig. 1) in the periods that were studied, colostral, transitional or mature. The farther away from labor that milk extraction was made, in the periods considered in our study, there is a progressive decrease in the concentration of secretory IgA (Fig. 2).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1998

Activation of epithelial cells in gastritis.

BACKGROUND: Helicobacter pylori is now recognised to be the major cause of antral gastritis and a risk factor for further development of gastric cancer. This infection results in local inflammation and a modification of gastric mucosal epithelial cell characteristics. Systematic investigation for the expression of the secretory component by gastric epithelium in a personal historical series of biopsy specimens showed the expression of this activation marker in 38% of the cases, 19% also showing clear signs of H. pylori infection. AIMS: To further appreciate the activation of epithelial cells in the chronic gastric inflammation associated with H. pylori infection and other types of gastritis without consideration of the grade of gastritis. METHODS: Punch gastric biopsies from 36 patients (10 patients with confirmed H. pylori gastritis, 16 patients with non-H. pylori gastritis and 10 controls) were tested for the expression of ICAM-1/CD54, HLA-DP, -DQ, -DR, secretory component and bcl-2 by immunofluorescence. RESULTS: Up-regulation of most markers was observed both in H. pylori and non-H. pylori gastritis, although secretory component, CD54 and DP expression was more closely associated with H. pylori gastritis. CONCLUSION: H. pylori infection appears to activate gastric epithelial cells more strongly than other types of gastritis. This suggests an active relationship between this bacterium and epithelial cells. Investigation of the up-regulationship between this bacterium and epithelial cells. Investigation of the up-regulation of secretory component, ICAM-1/CD54 or DP in gastric biopsies may serve as extensive markers in search of H. pylori gastric infections.

Adult↗
PubMed1995

Immunocompetent cells of the upper airway: functions in normal and diseased mucosa.

Secretory immunity is central in primary defense of the airway mucosa. B cells involved in this local immune system are initially stimulated in mucosa-associated lymphoid tissue, including tonsils and adenoids, and then migrate to secretory effector sites where they become immunoglobulin (Ig)-producing plasma cells. Locally produced Ig consists mainly of J-chain-containing dimers and larger polymers of IgA (pIgA) that are selectively transported through glandular cells by an epithelial receptor called secretory component or pIgR. Secretory antibodies perform surface protection by immune exclusion of soluble antigens as well as infectious agents. IgG can also participate in this primary defense because it reaches secretions by passive diffusion similar to IgE. However, the inflammatory properties of antibodies belonging to the latter two classes explain their involvement in mucosal immunopathology when elimination of penetrating antigens is unsuccessful. T helper (Th) cells activated in this process may by a Th2 profile of cytokines promote persistent inflammation with extravasation and priming of eosinophils. This mechanism appears to occur in the late-phase allergic reaction, perhaps driven mainly by interleukin-4 (IL-4) released from mast cells subjected to IgE-mediated degranulation. Eosinophils are potentially tissue-destructive cells, particularly after priming with IL-5. Cytokines also up-regulate adhesion molecules on vascular endothelium and epithelium, thereby enhancing migration of eosinophils and other leukocytes into the mucosa.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibody Formation↗
PubMed1985

Hepatic uptake and disposition of human polymeric IgA1 in perfused rat liver: evidence for incomplete biliary excretion and intrahepatic degradation.

The hepatic uptake of polymeric immunoglobulin A (IgA) is mediated by secretory component; the resulting secretory IgA is excreted intact into bile. To define the hepatic metabolism of polymeric IgA, we quantitated the uptake and transport of human polymeric IgA1 after a single pass through the perfused rat liver. Uptake of polymeric IgA1 was compared with that of asialoorosomucoid, a glycoprotein whose uptake is mediated by the asialoglycoprotein receptor. Single-pass hepatic uptake of 125I-polymeric IgA1 and of 125I-asialoorosomucoid averaged 18.0 +/- 3.1% (SE) and 71.8 +/- 2.8%, respectively. The uptake of 125I-polymeric IgA1 was inhibited by excess unlabeled polymeric IgA1 but not by asialoorosomucoid. Only 13.0 +/- 1.6% of the 125I-polymeric IgA1 extracted by the liver was excreted into bile, whereas three-fourths was released into the hepatic venous effluent in degraded form. Thus, both the uptake and biliary excretion of polymeric IgA1 by the rat liver are inefficient processes. Polymeric IgA1 follows two distinct pathways after uptake by the liver: a small proportion is excreted intact into bile, while the majority is degraded and released back into the circulation.

Animals↗
PubMed2005

Antibodies to the polymeric immunoglobulin receptor with different binding and trafficking patterns.

The polymeric immunoglobulin receptor (pIgR) has been proposed as a therapeutic target, but its potential depends on the efficiency of uptake and trafficking of the receptor ligand. Mouse monoclonal antibodies (Mabs) directed against pIgR, selected for strong binding to secretory component (SC) and secretory IgA (sIgA), were tested in a transcytosis assay in 16HBEo--cells (human bronchial epithelial cell line) transfected with human pIgR. Intracellular trafficking was followed by confocal microscopy. Mabs fell into two classes. For two Mabs, transcytosis from basolateral to apical surface is rapid, unidirectional, and little Mab is retained in the cell. For three Mabs, basolateral to apical transcytosis occurs to a significantly lesser extent, reverse transcytosis is permitted, and some of the Mab is retained in the perinuclear region even after 24 h. When tested for their ability to recognize and immunoprecipitate pIgR with systematic truncations and deletions of the five immunoglobulin (Ig)-like domains, all Mabs bound to the fifth Ig-like domain, but three of them also bound to the C-terminal region of pIgR near the plasma membrane. Different binding sites probably account for the different trafficking of these Mabs and may predict differential therapeutic utility.

Animals↗
PubMed1987

[Comparative analysis of the subpopulation of immunocompetent cells and the secretory IgA system in neonatal and maternal milk].

To examine the local immunity of the newborn and maternal mammary glands the distribution of regulatory lymphocyte subsets, Ia-positive cells, free secretory component (Sc) and secretory IgA (SIgA) has been studied in maternal and neonatal milk. In the maternal milk there was a positive correlation between the relative number of Ia-positive cells and the level of SIgA, and a reverse correlation between the percentage of cytotoxic (suppressor) cells and free Sc level. No such correlations were observed on the neonatal milk. A high level of It-positive cells in the neonatal milk suggests a high functional activity of the local immunity in the mammary gland of the newborn. A high Sc level and a very low SIgA level were found in the neonatal milk. The relative immaturity and autonomy of the local immunity were observed in the neonatal mammary gland.

Colostrum↗
PubMed1985

Subclass distribution and molecular form of immunoglobulin A hemagglutinin antibodies in sera and nasal secretions after experimental secondary infection with influenza A virus in humans.

Serum and nasal wash specimens from 13 human volunteers undergoing experimental secondary infection with influenza A/Peking/2/79 (H3N2) wild-type virus were examined for the molecular form and subclass distribution of immunoglobulin A (IgA) antibodies to the viral hemagglutinin (HA). Nasal IgA antibodies were polymeric and did not bind radiolabeled secretory component, indicating that they were secretory IgA antibodies. Both IgA1 and IgA2 antibodies were detected; however, IgA1 accounted for most of the rise in IgA anti-HA levels seen after infection. In serum virtually all of the IgA HA antibodies were of the IgA1 subclass. Furthermore, the serum antibodies were predominantly polymeric and were capable of binding radiolabeled secretory component. These results suggested that the serum IgA antibodies to HA were of mucosal origin and that influenza A virus HA preferentially stimulates an IgA1 response.

Hemagglutinins↗
PubMed1980

Mucosal receptor for IgA in the breast-fed neonate.

Immunoglobulin A from human milk binds to neonatal buccal cells. Pretreatment of the cells with anti-secretory component antiserum blocks this binding, suggesting that secretory component (SC) contributes to the adhesive process. The concentrations of SC in saliva of preterm neonates is lower than that of full-term infants. This may lower the effectiveness of mucosal immunity passively transferred from the mother.

Breast Feeding↗
PubMed1988

Immunoglobulin A receptor of rat small intestinal enterocytes is unaffected by aging.

The receptor for polymeric immunoglobulins is responsible for the transport of immunoglobulin A (IgA) through epithelial cells and its subsequent delivery to mucosal surfaces. We have extended our previous studies of the IgA receptor in the liver of the aging Fischer rat to include the small intestine. Basolateral membrane-enriched fractions prepared from rat small intestinal enterocytes exhibit a single binding site for dimeric IgA. This receptor is specific for molecules that interact with rat secretory component, e.g., rat dimeric IgA and IgM and human polymeric IgA but not human monomeric IgA or rat secretory IgA. Inhibition of binding by rabbit-antirat secretory component also indicated that binding is specific for secretory component. Both liver and intestinal membranes showed virtually identical binding specificity. Membranes from crypt cells show increased IgA binding (320 fmol bound per milligram protein) compared with villous cells (105 fmol bound per milligram protein); however, other than increased binding, crypt cells show the same binding characteristics as villous cells. In contrast to our previous findings, in which liver plasma membranes from old rats showed a four-fold decrease in IgA binding compared with young adult rats, membrane fractions from rat enterocytes showed no alterations in dimeric IgA binding with increased age.

Aging↗
PubMed1989

The polymeric immunoglobulin A receptor is present on hepatocytes in human liver.

A monoclonal antibody raised against human colostrum secretory component produced even staining of hepatocyte plasma membranes, as well as bile duct lining cells, in all sections examined from eight normal and three abnormal human livers. Human bile samples incubated with free secretory component degraded it to varying extents, probably proteolytically; true levels of free secretory component will therefore often be higher than those reported. It seems likely that human liver resembles that of other mammals in transferring polymeric IgA through hepatocytes to the bile by means of the polymeric IgA receptor.

Bile↗
PubMed1979

Translocation of dimeric IgA through neoplastic colon cells in vitro.

We studied the translocation of dimeric IgA across epithelium, using neoplastic human colon cells in culture as a source of epithelial cells, and immunoelectronmicroscopy with peroxidase-labeled antigens and antibodies. The cells had some of the ultrastructural characteristics of normal, mature epithelial cells, i.e., polarity, desmosomal junctions, and secretory component on their basal and lateral plasma membranes. Horseradish peroxidase-labeled dimeric IgA, exposed to the cells at 0 degrees C, bound selectively to secretory component on the cell surfaces. At 37 degrees C, the bound dimeric IgA was taken into the cells by endocytosis and transported apically through the cytoplasm in vesicles. After 30 min, IgA was discharged across the apical surface. Neither colchicine (10(-4) M) nor cytochalasin B (10(-5) M) interfered with binding or endocytosis of dimeric IgA, but colchicine inhibited intracellular transport of the IgA-containing vesicles. These experiments demonstrated that dimeric IgA can be transported through living intestinal epithelial cells in vitro. The transport includes 1) specific binding of IgA dimers to secretory component on plasma membranes, 2) endocytosis of IgA in vesicles, 3) transcytoplasmic transport of the IgA-containing vesicles by a process involving microtubules, and 4) discharge of IgA at the apical surfaces.

Binding Sites, Antibody↗
PubMed1987

The transport and metabolism of bovine IgM.

IgM is present in cows milk, is able to bind secretory component (SC), has a purported role as a secretory immunoglobulin in other species and has been identified with various antibody functions in cows milk. To determine the origin of cows milk IgM, we administered extrinsic 131I-IgM to lactating cows with cannulated bile and parotid ducts and studied the kinetics of its disappearance from serum and its appearance in milk, bile and parotid saliva for 60 hr post-injection. Pentameric IgM appeared to require a long equilibration time and disappeared from serum with a T1/2 of 40 hr. The transport of IgM into bile also appeared biphasic. Results showed that no 131I-IgM was transported intact into parotid saliva and that most radioactivity in milk and bile after 6 hr was in the form of low mol. wt, TCA-precipitable fragments rather than of the size of a pentamer. During the first 24 hr only 0.83% of the administered dose reached the milk in pentameric form, nevertheless, isotope dilution calculations indicated that nearly all milk IgM was derived from serum. During a 12 hr collection period, corresponding to one milking, greater than 200 mg of serum IgM is secreted in milk. During the first 24 hr, only 0.70% of the administered IgM reached the bile as a pentamer. It was calculated that 50% of the pentameric IgM in bile, 3 hr after administration, was serum-derived. Twenty-five per cent of the IgM appearing in bile and ca 10% of the IgM appearing milk, becomes associated with secretory component. A hypothesis to explain the degradation associated with this inefficient transport mechanism is presented.

Animals↗
PubMed1992

Effect of intrajejunal elemental diet perfusion on jejunal secretion of immunoglobulins, albumin, and hyaluronan in man.

The aim of this work was to study the jejunal secretion of immunoglobulins (Ig), albumin, and hyaluronan in response to jejunal perfusion of an elemental diet. A four lumen tube with a proximal occluding balloon at the angle of Treitz was used for jejunal perfusion in seven healthy volunteers (mean age 23 years). The length of the test segment was 40 cm. The jejunum was successively perfused with a control electrolyte solution for 80 minutes and with an elemental diet (containing 20.5 milligrams of free amino acids and 104.2 milligrams of oligosaccharides) for 100 minutes. The jejunal fluid concentrations of albumin, IgG, monomeric IgA (m-IgA), polymeric IgA (p-IgA), IgM, secretory component, and hyaluronan were measured and their jejunal outputs calculated. Within 20 minutes of starting perfusion with the elemental diet there was a significant increase in the secretion rates of albumin (x3.3), IgG (x5), M-IgA (x3.7), p-IgA (x2), IgM (x2), and secretory component (x1.6), but the hyaluronan secretion rate was not changed. The increase in m-IgA, p-IgA, IgM, and secretory component output suggests that intestinal perfusion of an elemental diet results in stimulation of secretory immunity. The increase in albumin and IgG output probably reflects a nutrient induced leakage from the plasma compartment.

Adult↗
PubMed1987

Secretory immunoglobulin deposits in renal glomeruli of children with extrahepatic biliary atresia: studies in a human counterpart of experimental ligation of the bile ducts.

Experimental ligation of the biliary tract often results in glomerular deposits of polymeric IgA commonly associated with secretory component. These studies offer evidence that, in animals, hepatobiliary transport of polymeric IgA, which is of mucosal origin, is crucial for its clearance from the serum. We studied a human counterpart of bile duct ligation--extrahepatic biliary atresia--for the presence of secretory or polymeric immunoglobulins in renal glomeruli. Kidney was available at autopsy as paraffin or frozen blocks from 24 patients with biliary atresia and age-matched controls (5 weeks to 5 years old). Several of the patients had undergone portoenterostomy (Kasai procedure) or liver transplantation. Immunohistologic studies showed glomerular (often mesangial) deposits of IgA in 10 of 24 and IgM in 16 of 24 specimens. The differences with controls were highly significant for IgA but not for IgM. In frozen sections, secretory component was positive in glomeruli in seven of 12 specimens. In vitro glomerular binding of purified secretory component to glomeruli was shown in four of 12 samples, including three with IgM only. This last observation suggests that IgM in some of these patients was polymeric and thus derived from a mucosal source. Our study shows that in humans with biliary atresia, secretory IgA, polymeric IgA, and possibly polymeric IgM are deposited in glomeruli. The study confirms the occurrence of renal immunopathologic findings in liver disease and supports the existence of an active hepatobiliary immunosecretory transport mechanism even at the early age of these patients.

Biliary Atresia↗
PubMedDate not supplied

[Immunoglobulins in serum and seminal fluid in patients with sperm agglutination].

Serum immunoglobulins and immunoglobulins in the seminal fluid were determined in 32 men with normospermia without agglutination and in 37 men with normospermia with agglutination. In the seminal fluid also secretory IgA and the secretory component were recorded. The values of serum immunoglobulins were more or less the same. So were the IgG values in the seminal plasma of both groups. IgA was found more frequently in the seminal plasma of patients with agglutination. IgM was not found at all. Secretory IgA and the secretory component were for the most part found in the seminal plasma of patients with normospermia and agglutination. The finding of secretory IgA and the secretory component gives an insight into the local synthesis of sperma-antibodies.

Humans↗
PubMed1985

Local immunodeficiency of the intestinal mucosa--a contribution to etiopathogenesis of recurrent urticaria and diarrhoea.

The case of a 10 month-old girl with a history of recurrent urticaria and diarrhoea is presented. Immunological study was carried out and secretory component in sputum, duodenal juice and stool was not found, while IgA was detected. Peroral biopsy of intestinum was also carried out and histology revealed partial villous atrophy. Immunofluorescent staining showed only a few IgA and IgG producing cells scattered within the villous stroma, while the IgM producing cells were increased in number. Serum concentration of IgA, IgM and particularly IgG was increased. Both parents had measurable IgA in the serum, however, the secretory component was not detectable neither in mother nor in father. The deficiency of secretory component and deficiency of IgA producing cells in the jejunal villous stroma led to local immunodeficiency of the intestinal mucosa and that caused recurrent urticaria and diarrhoea in the girl presented.

Antigen-Antibody Complex↗
PubMed1981

Ultrastructural evidence of transport of secretory IgA across bronchial epithelium.

To define the mechanisms for transport of secretory IgA (sIgA) into bronchial secretions, IgA and secretory component in human bronchial mucosa were localized by immunoelectron microscopy. IgA was identified in plasma cells located near glandular epithelial cells and on the basolateral plasmalemma and endocytic vesicles of the epithelial cells, especially of mucous cells. Secretory component was localized to the perinuclear spaces, endoplasmic reticulum, Golgi complexes, basolateral plasmalemma and endocytic vesicles of glandular epithelial cells, as well as those of ciliated epithelial cells. These findings are consistent with a model for IgA transport in which IgA dimers, synthesized in plasma cells, are complexes with secretory component on the basolateral plasmalemma of epithelial cells in bronchial glands and transported across the cells in endocytic vesicles to the gland lumina.

Biological Transport, Active↗