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PubMed1983

A simple method for determining polymeric IgA-containing immune complexes.

A simplified assay to measure polymeric IgA-immune complexes in biological fluids is described. The assay is based upon the specific binding of a secretory component for polymeric IgA. In the first step, multimeric IgA (monomeric and polymeric) immune complexes are determined by the standard Raji cell assay. Secondly, labeled secretory component added to the assay is bound to polymeric IgA-immune complexes previously fixed to Raji cells, but not to monomeric IgA immune complexes. To avoid false positives due to possible complement-fixing IgM immune complexes, prior IgM immunoadsorption is performed. Using anti-IgM antiserum coupled to CNBr-activated Sepharose 4B this step is not time-consuming. Polymeric IgA has a low affinity constant and binds weakly to Raji cells, as Scatchard analysis of the data shows. Thus, polymeric IgA immune complexes do not bind to Raji cells directly through Fc receptors, but through complement breakdown products, as with IgG-immune complexes. Using this method, we have been successful in detecting specific polymeric-IgA immune complexes in patients with IgA nephropathy (Berger's disease) and alcoholic liver disease, as well as in normal subjects after meals of high protein content. This new, simple, rapid and reproducible assay might help to study the physiopathological role of polymeric IgA immune complexes in humans and animals.

Antigen-Antibody Complex↗
PubMed1982

Increased rates of polymeric IgA synthesis by circulating lymphoid cells in IgA mesangial glomerulonephritis.

Recently we have described the existence of high levels of polymeric IgA, partially as immune complexes, in the serum and kidney from patients with IgA mesangial glomerulonephritis. As these patients often have macroscopic haematuria, following upper respiratory tract infections, our working hypothesis in this paper was that circulating lymphocytes from secretory tissues after viral stimulus could produce in these patients a large amount of polymeric IgA. To test it, peripheral blood lymphocytes (PBL) from patients and controls were cultured for seven days in the presence or absence of pokeweed mitogen (PWM). In cell culture supernatants immunoglobulin synthesis was measured by RIA and the proportion of polymeric and monomeric IgA was determined on Ultrogel Ac A22 column. There was no difference in spontaneous production of immunoglobulins between patients and controls. On the contrary, the IgA synthetized by PWM-stimulated PBL was significantly higher in patients than in controls. The percentages of IgA with molecular weight between 600,000 and 250,000 after supernate fractionation were significantly higher in patients than in controls. The true nature of polymeric IgA was confirmed by their ability to bind secretory component, the existence of covalent structures, and the decrease of the larger forms of IgA after reduction and alkylation. The percentage of IgA producing cells binding secretory component was significantly higher in patients than in controls (69 +/- 21 versus 44 +/- 27) after seven days of culture. IgM and IgG produced in patient culture were similar to controls. These results show that mitogen stimulated PBL from patients with Berger's disease synthetized a large amount of true polymeric IgA. It is suggested that a similar situation could occur in vivo after viral of other stimuli.

Cells, Cultured↗
PubMed1984

Immunohistological study of malignant diffuse mesotheliomas of the pleura.

Paraffin sections from fifteen cases of malignant diffuse mesothelioma of the pleura and five cases of bronchial adenocarcinoma infiltrating the pleura were examined with an antiserum specific for factor VIII related antigen and with antisera against various epithelial markers: keratin, carcinoembryonic antigen (CEA), fat globule membrane antigen and secretory component. In all adenocarcinomas all the epithelial markers were present whereas the factor VIII related antigen was absent. The distribution of the fat globule membrane antigens, keratin, secretory component and factor VIII related antigen varied from one mesothelioma to another. The mesotheliomas were generally negative for CEA. The three mesotheliomas which were positive for CEA were also positive for alcian blue after hyaluronidase treatment. Amongst the markers used, CEA seems the most useful for the differential diagnosis between carcinoma and mesothelioma. However, the simultaneous detection of several markers allows the characterization of various phenotypes. Some of them are close to the phenotypes of true adenocarcinoma. A relation between a given phenotype and the biological behaviour of the tumour has still to be demonstrated.

Adenocarcinoma↗
PubMedDate not supplied

Changes in IgA following varying degrees of biliary obstruction in the rat.

Polymeric IgA is rapidly transported from blood to bile by the rat liver. The effect of varying degrees of biliary obstruction on this transport process was studied. IgA concentrations were measured by radioimmunoassay. Serum IgA concentrations increased progressively, and IgA output in bile declined with increasing bile duct obstruction. The decline in bile IgA output was explained by both diminished bile flow and decreased concentrations of IgA in bile. Very little polymeric IgA was present in normal rat serum. In contrast, using column chromatography on Ultrogel AcA 22, increases in serum IgA associated with cholestasis were shown to be due to increments in polymeric IgA. Serum IgA was a more sensitive indicator of cholestasis than was serum alkaline phosphatase. IgA and secretory component were found, using indirect immunofluorescence, surrounding bile canaliculi and on or adjacent to the hepatocyte plasma membrane lining the sinusoids. With biliary obstruction, staining for IgA and secretory component intensified markedly near the bile canaliculi. We conclude that: (a) polymeric IgA must be efficiently removed from serum by the normal rat liver; (b) even minimal cholestasis impairs IgA output into bile, and (c) impairment of IgA transport during cholestasis appears to occur at or near the canalicular membrane.

Animals↗
PubMed1993

Development of immune response markers in the trachea in the fetal period and the first year of life.

Immunoglobulin (Ig)-producing cells, T cells (CD3) and epithelial expression of secretory component (SC) and HLA class II determinants (DR, -DP, -DQ) were studied by immunohistochemistry in 16 fetal and 15 postnatal specimens from the tracheal wall. Small amounts of secretory component (SC) was present in the tracheal surface and gland epithelium in the fetal period and increased towards term. A few IgM-, IgD- and IgG-producing cells were present in some fetal specimens but no IgA- and IgE-producing cells were found. Only very few CD3+ T-cells were present in fetal specimens and intraepithelial T-cells were virtually absent until after birth. Premature infants that lived for 1 week had less SC epithelial expression than mature infants of the same age. The density of CD3+ T-cells, IgA-, IgM-producing cells as well as the epithelial SC expression increased rapidly after birth. Epithelial MHC class II expression was absent in fetal specimens. HLA-DR was detected on the apical border of the surface epithelium one week after birth and was extensively expressed throughout the remaining postnatal period. Epithelial DP and PQ expression were virtually absent during this same period. These features probably reflect local activation of the immune system in response to environmental factors.

Antibody-Producing Cells↗
PubMed1986

Class distribution of immunoglobulin-containing plasma cells in the stroma of medullary carcinoma of breast.

A class distribution of plasma cells associated with the stroma in twenty-eight cases of medullary carcinoma of the breast was investigated by an unlabeled immunoperoxidase method. The stroma of the medullary carcinomas tested was found to contain predominantly IgG plasma cells except in two cases. Stroma of the other types of breast carcinoma, including ten cases of papillo-tubular carcinoma, five cases of scirrhous carcinoma, and six cases of medullary tubular carcinoma, contained predominantly IgG plasma cells, although few plasma cells were associated with carcinoma tissues in the latter group. Plasma cells associated with control specimens, including normal breast, fibroadenoma, cystic disease, and intraductal papilloma, were found to be predominantly of IgA type. Few carcinomatous epithelial cells contained secretory components in the cytoplasm, while a number of cells positive for secretory components were observed in acinar and ductular epithelia of normal breast tissues and in benign proliferative lesions of the breast. It is suggested that the lymphoid cells infiltrating the stroma of medullary carcinoma represent a sign of host immune response against the carcinoma cells which is related to the well-known favorable prognosis associated with this tumor.

Adenocarcinoma↗
PubMed1984

Selective transport of serum-derived IgA into mucosal secretions.

The relative contribution of serum-derived and locally produced IgA has been estimated in sheep mammary secretion at various stages of lactation by comparing the transport of radiolabeled IgA and IgG2 from serum to secretions. During early and mid-lactation, but not during involution, serum IgA was selectively transported to mammary secretion on a large scale; in comparison, there was no transport of serum IgA into intestinal secretion. Estimates of local production indicated that the bulk of the IgA in mammary involution secretion and intestinal secretion was locally produced, whereas there was no evidence for local production of IgA in early or mid-lactation secretion. Our studies reveal an inverse relationship between the extent of local production of IgA by plasma cells underlying secretory epithelia and the selective transport of IgA from serum. This finding suggests that selective transport of serum IgA occurs at a number of mucosal sites, but is dependent on secretory component availability, because where local production is predominant, there are fewer secretory component molecules available for serum IgA transport. For this reason, bile transport of IgA does not represent a unique mechanism for the removal of IgA from serum.

Animals↗
PubMedDate not supplied

Local immune system in human adult and fetal larynx.

Using immunofluorescent and histopathologic techniques, we studied the distribution and secretory activity of the glands of the larynx from 51 adults and 15 human fetuses. Glandular buds were first observed at the 12th fetal week and glandular distribution became evident from the 16th fetal week. In the adult larynx, intraepithelial and submucosal glandular distribution was observed in each specimen. Immunofluorescent studies revealed the diffuse fluorescence for IgA not only in the submucosal or periglandular connective tissue are but also in the intraepithelial and submucosal glands. Secretory component (SC) synthesis was found mainly in each serous-type glandular epithelium or acinus. In the submucosal or periglandular area, IgA-producing plasma cells were numerous. In contrast, there was little fluorescence for IgA in the fetal laryngeal tissues. Secretory component, however, was found in each serous-type glandular epithelium or acinus from the 16th week. Our observations suggest that local immune system by secretory IgA is active in the adult larynx, and the production of SC is inherently acquired in the fetal larynx.

Adult↗
PubMed1980

Ontogeny of secretory immunity: levels of secretory IgA and natural antibodies in saliva.

In 187 healthy subjects from 2 months to 27 years of age, secretory IgA and free secretory component were assayed in samples of whole saliva obtained before and after stimulation with lemon juice. Antibody titers against Escherichia coli O antigens and against rabbit erythrocytes were also dosed in unstimulated saliva. Secretory IgA, undetectable in newborns, was present in all 2-month-olds tested in both unstimulated and stimulated saliva; thereafter secretory IgA levels increased progressively, reaching adult values by 6 to 8 years in unstimulated saliva and already by 2 to 4 years in stimulated saliva. The antibody titers assessed in unstimulated saliva followed a similar pattern also reaching adult values by 6 to 8 years. On the other hand, free secretory component levels showed no significant variation with age in unstimulated saliva whereas a slight increase was observed in the first year of life in stimulated saliva.

Adolescent↗
PubMed1985

Molecular forms of tear IgA and distribution of IgA subclasses in human lacrimal glands.

Tears and sera from 14 subjects were analyzed for IgA levels by radioimmunoassay by use of secretory IgA standards for tear samples and monomeric IgA standards for serum samples. [corrected] Tears from subjects without conjunctival inflammation contained 93% polymeric IgA (pIgA) and 7% monomeric IgA; tears from subjects with conjunctival inflammation had less pIgA (79%). Biopsy specimens of 11 lacrimal glands and one accessory lacrimal gland were obtained from 12 additional subjects. Tissues were stained with polyclonal antisera for immunoglobulins, J chain, and secretory component. In addition, tissues were stained for IgA subclasses with monoclonal reagents specific for IgA1 and IgA2. IgA plasma cells predominated over other types of plasma cells, and most were J chain positive. Secretory component, although absent from the interstitium of the gland, was found in most acinar and ductal cells. The average proportion of IgA1 to IgA2 cells was 56% to 44%. We concluded that the lacrimal system of the human resembles other exocrine systems in the production of predominantly pIgA and the nearly equal occurrence of IgA1 and IgA2 plasma cells.

Adolescent↗
PubMed1980

IgA1 proteases from Haemophilus influenzae, Streptococcus pneumoniae, Neisseria meningitidis, and Streptococcus sanguis: comparative immunochemical studies.

IgA1 proteases from H. influenzae, N. meningitidis, S. pneumoniae, and S. sanguis were compared with respect to site of cleavage in the IgA1 molecule and EDTA sensitivity. Proteases from S. sanguis and S. pneumoniae cleaved the Pro (227)-Thr (228) bond within the hinge region of the alpha 1 chain and were inhibited by EDTA. H. influenzae IgA1 protease cleaved the Pro (231)-Ser (232) peptide bond. The activity of IgA1 proteases from H. influenzae and N. meningitidis was unaffected by EDTA. Purified and denatured alpha 1 chain was cleaved only in the hinge region. Other component chains of secretory IgA (secretory component, light and J chains) were not susceptible. In addition to IgA1 protease, S. pneumoniae released exo- and endoglycosidases that removed a considerable portion of carbohydrate side chains of IgA1; this activity was absent from crude IgA1 protease preparations of the other three bacterial species. Association in vitro of polymeric IgA1 with SC did not inhibit the degradation of IgA1 proteases. The considerable resistance of secretory IgA to cleavage by IgA1 proteases may be explained in part by the presence of IgA1 protease-neutralizing antibodies in secretory IgA.

Amino Acid Sequence↗
PubMed1986

Polymeric immunoglobulin receptor expressed in MDCK cells transcytoses IgA.

We expressed cDNA for the rabbit polymeric immunoglobulin receptor in polarized Madin-Darby Canine Kidney epithelial cells, which normally do not produce this receptor. The receptor appeared to function as in vivo; dimeric IgA was transported from the basolateral to the apical surface and released into the apical medium, together with the cleaved fragment of the receptor, known as secretory component. This system enabled us, for the first time, to study quantitatively IgA transcytosis in vitro and thus make the following observations. First, greater than 90% of the newly made receptor that is ultimately cleaved to secretory component and released into the apical medium goes first to the basolateral surface. Second, transport of the receptor does not depend on ligand binding. Third, transcytosis of bound ligand has a t 1/2 of 30 min.

Animals↗
PubMed1985

The clinical relevance of classes of immunoglobulins on spermatozoa from infertile and vasovasostomized males.

Following reversal of vasectomy, conceptions occur even when antisperm antibodies are present in the seminal plasma, but this is most unusual in men with similar titers of such antibodies who are spontaneously infertile. To clarify the differences between antisperm antibodies occurring in infertile men and those associated with vasectomy reversal, we have studied 23 spontaneously infertile men and 22 men who underwent vasectomy reversal, all of whom had antisperm antibodies detected in seminal plasma by the same tray agglutination test. The class of antibody on spermatozoa was defined by a double-antibody technique using diluted rabbit anti-human IgG, IgM, or IgA or secretory component, followed, after washing, by 125I-labeled donkey anti-rabbit Ig. The results have shown that similar amounts of IgG and IgM were present on the spermatozoa, but infertile men had significantly more IgA and especially more secretory component than men who underwent vasectomy reversal. This was associated with significantly greater impairment of penetration of cervical mucus in the former group. It appears that the type of antibody on the spermatozoa may vary according to the stimulus for its production.

Antibodies, Anti-Idiotypic↗
PubMed1998

A composite DNA element in the promoter of the polymeric immunoglobulin receptor regulates its constitutive expression.

The polymeric immunoglobulin receptor (pIgR), which is constitutively expressed on the basolateral surface of secretory epithelial cells, mediates external translocation of polymeric IgA and pentameric IgM (collectively called pIg) to exocrine secretions. A high level of synthesis must be maintained because the receptor is continuously cleaved to release bound secretory component (SC) in secretory IgA and secretory IgM, as well as free SC from unoccupied receptor. We have isolated the promoter of the pIgR gene and identified a short activating region that is required for the expression of pIgR promoter-driven reporter genes. This region contained an E-box and an inverted repeat sequence (IRS). Gel electrophoresis mobility shift assays with nuclear extracts from different pIgR-expressing epithelial cell lines demonstrated proteins that bind independently to both the E-box and the IRS sequence of the pIgR promoter. In addition, a DNA probe that contained both the E-box and the IRS gave rise to a larger complex that could not be competed by either element on its own. Binding was confirmed by DNase I footprinting of the E-box and IRS sequences with nuclear extracts, and by dimethyl sulfide footprinting in living HT-29 epithelial cells. Finally, a mutation in the pIgR promoter that inhibited protein binding to the E-box and the formation of the larger complex, abolished activated transcription from the reporter gene.

Base Sequence↗
PubMed1984

Immunohistochemical characterization of cellular immunoglobulins and epithelial marker antigens in Warthin's tumor.

Lymphoid and epithelial cell marker studies based on paired immunofluorescence staining were performed on ethanol-fixed specimens from six Warthin's tumors of the parotid gland. A polyclonal pattern of isotype and light-chain expression was demonstrated for immunoglobulin-producing cells and afforded definitive evidence for the reactive nature of B-cell proliferation. The average percentages of IgG, IgA, IgM, IgD, and IgE immunocytes were 48.6, 38.5, 8.9, 3.3, and 0.7, respectively. The percentages of J-chain-positive cells within the first four isotypes were 11.3, 47.0, 67.2, and 64.4. Both features were more typical of immune responses in lymphoid tissues than in exocrine glands. In five of the six specimens, IgE was present in a prominent lacy pattern in some follicular centers, often extending to lymphocyte membranes of the mantle zone. Mast cells positive for IgE were seen in all cases. The two latter features indicate that type 1 hypersensitivity might contribute to the lesion. Parts of the tumor epithelium stained selectively for dimeric IgA and secretory component (SC), signifying secretory capacity. In addition, lactoferrin and carcinoembryonic antigen (CEA) occasionally were present in a narrow cytoplasmic luminal rim. Carcinoembryonic antigen was also seen in papillary epithelial projections. Lysozyme was found in isolated epithelial cells, whereas amylase was completely lacking. Except for the presence of CEA, this pattern of epithelial markers resembled that seen in striated ducts of normal salivary glands.

Adenolymphoma↗
PubMed1998

The influence of nerves on the secretion of immunoglobulin A into submandibular saliva in rats.

1. The influence of sympathetic and parasympathetic nerve stimulations on salivary secretion of immunoglobulin A (IgA) was studied in the submandibular glands of anaesthetized rats by stimulating the nerve supplies with bipolar electrodes. 2. Although the flow of saliva from sympathetically stimulated glands was only 23% of that from parasympathetically stimulated glands the output of IgA was over 2-fold greater. This difference was attributable to influences of the nerves on IgA secretion through the epithelial cell polymeric immunoglobulin receptor-mediated pathway, as Western blotting with specific antibodies to IgA and secretory component revealed that secretory IgA (SIgA) dominated in all saliva samples. 3. Study of saliva secreted in sequential periods of nerve stimulation or following rest pauses suggested that SIgA secretion occurred in the absence of stimulation but this was upregulated 2.6- and 6-fold by parasympathetic and sympathetic nerve stimulations, respectively, compared with the calculated unstimulated rate. 4. The IgA content of extensively stimulated glands was 77% of levels in unstimulated contralateral control glands despite a secretion into saliva equivalent to almost 90% of the glandular IgA content. The IgA may be synthesized and secreted by glandular plasma cells at a rate which exceeds demand and/or such synthesis may be upregulated by nerve impulses. 5. The results indicate that salivary secretion of SIgA is upregulated by nerve impulses and that sympathetic nerves induce a greater effect than parasympathetic nerves.

Animals↗
PubMed1985

Structural integrity of host defense factors in dental plaque.

The structural integrity of immunoglobulin A (IgA), IgG, and IgM and lactoferrin in dental plaque fluid samples from two populations of Colombian children with contrasting levels of dental caries was examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by electrophoretic transfer to nitrocellulose. The immune factors or their fragments or both were detected with monospecific antibody conjugated with horseradish peroxidase. All the immune factors examined were extensively degraded, although there appeared to be small amounts of intact IgA and IgG in some samples. Analysis of the samples with antibody to secretory component showed that secretory IgA as well as serum IgA was degraded. IgG appeared to be cleaved into two major fragments, one fragment having a relative mobility similar to the F(ab')2 fragment of IgG and the other a relative mobility slightly greater than Fc. IgM and lactoferrin were virtually completely degraded. There was no apparent relationship between the fragmentation patterns of IgA and IgG in the plaque fluid samples from the two communities and their susceptibility to dental caries.

Dental Plaque↗
PubMed1989

Human milk feeding enhances the urinary excretion of immunologic factors in low birth weight infants.

The effects of fortified human milk feedings on the urinary excretion of lactoferrin, lysozyme, secretory component, IgA, and secretory IgA antibodies to Escherichia coli O antigens were investigated in very low birth wt infants. Infants were maintained on either a human milk or a cow's milk preparation. The amounts of each immune factor that were ingested and excreted were quantified during balance studies conducted at 2.5 and 5 wk of age. Serum levels of these immune factors were similar in both feeding groups. The urinary excretion of all factors except lysozyme was 7- to 150-fold greater in infants fed human milk than in those fed cow's milk formula. IgA was the only factor for which the amount of the factor excreted correlated with the amount ingested. Fragments as well as whole molecules of lactoferrin were found in the urine of the infants fed human milk, but the molecular sizes of the excreted proteins exceeded those normally filtered by the kidneys. Therefore, the genesis of the enhanced levels of host defense factors in the urine of infants fed human milk is not clear. Gastrointestinal absorption and subsequent renal excretion as well as enhanced production of immune factors in the infant's urinary tract are possible explanations.

Humans↗