SEARCH · Search PubMed

Results for “Secretory Component”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 775 records · Page 43Linked to original sources

PubMed1977

Studies on translocation of immunoglobulins across intestinal epithelium.

The issue of how immunoglobulins are transported across the intestinal epithelium into the gut lumen was examined by immunohistocytochemical techniques. IgA, IgM, IgG and secretory component (SC) in human small intestine at light and electron microscopic levels were localized by the peroxidase-labeled antibody technique. By light microscopy, IgA, IgM and SC, but not IgG, were found associated with columnar epithelial cells in gland crypts. By electron microscopy, SC was found in the perinuclear membranes, rough endoplasmic reticulum and Golgi complexes of these cells. IgA and IgM as well as SC were found in the basolateral plasma membranes and cytoplasmic vacuoles of the cells. It was concluded that in the human small intestine 1) SC is synthesized by columnar secretory epithelial cells; 2) IgA and IgM, but not IgG, are transported through these cells; 3) IgA and IgM could combine during transport with SC on plasma membranes or within the cytoplasm of these cells. In additional experiments, in vitro binding of peroxidase-labeled dimeric IgA to specific sites, corresponding to the sites of SC, on human intestinal epithelial cells, was demonstrated.

Biological Transport↗

PubMed1982

[Detection of secretory immunoglobulin A in vaginal fluid of hysterectomised women].

Secretory immunoglobulin A (S-IgA) or the secretory component (SC) in vaginal fluid of hysterectomised patients were established by means of simple and double immunodiffusion, according to Mancini or Ouchterlony, using an S-IgA standard. Since S-IgA was recorded from vaginal fluid, general questions were raised for origin and transport mechanisms of this localised immunoglobulin.

Female↗

PubMed1993

An immunohistochemical study of adenoid cystic carcinoma of the external auditory canal.

Specimens from five cases of adenoid cystic carcinoma of the external auditory canal were studied by immunohistochemical staining, and findings were compared with those from adjacent non-neoplastic tissues containing ceruminous glands. In the ceruminous gland, cytokeratin showed diffuse positive staining, while myoepithelial cells were stained for smooth muscle actin, desmin, S-100 protein and vimentin. The epithelial markers used were cytokeratin, carcinoembryonic antigen and secretory component and stained at various densities the inner cells of the tubular component and duct-lining cells in the cribriform component of tumor tissues. In contrast, the muscular markers, smooth muscle actin and desmin, and the mesenchymal marker, vimentin, were positive in the outer cells of the tubular component and in the cyst-lining cells of the cribriform component. S-100 protein immunoreactivity showed paradoxical results; positive findings occurred in the myoepithelial cells of the ceruminous glands and in the inner cells of the tubular component and duct-lining cells of the cribriform component of the tumor. Present findings demonstrate that adenoid cystic carcinoma of the external auditory canal had dual epithelial and myoepithelial differentiation and can mimic the ceruminous glands of the auditory canal.

Actins↗

PubMed1987

The immune response of the lacrimal gland to antigenic exposure.

This study probed the influence of antigenic exposure on the immunological response of the lacrimal gland. We utilized the germfree rat as a model system to monitor tissue and tear immunoglobulin changes following transfer of these animals into an antigen-laden, conventional environment. The number of IgA- and IgM-containing cells in the lacrimal glands of germfree rats was 5 to 8 fold less than that of conventional controls. This reduced immunological expression in germfree animals also extended to tear IgA levels, which were significantly decreased. No effect of germfree conditions was found on the tear content of secretory component (SC). Transfer of rats from a germfree to a conventional environment resulted in a significant increase in the number of IgA- and IgM-containing cells in the lacrimal gland. By four weeks after 'conventionalization', the number of Ig-containing cells in lacrimal tissue was similar in both ex-germfree and conventional rats. In addition, 'conventionalization' led to a significant increase in the tear content of IgA: within four weeks following exposure to a conventional environment, tear IgA levels in ex-germfree rats were equivalent to those of age-matched, conventional controls. Overall, our results demonstrate that the secretory immune system of the lacrimal gland reacts to antigenic challenge with an increased immunological response.

Animals↗

PubMed1981

Local immune system in the developing fetal larynx.

Using histopathological and immunofluorescent techniques, we investigated the development of the glandular system of the larynx from 12 human fetuses. Glandular buds were first observed at the fourth month of gestation and glandular distribution became evident from the fifth month in the larynx. Ciliated or nonciliated epithelium covered the cavity of the larynx, with the exception of the true vocal cord. Immunofluorescent examination revealed the presence of IgG in the fetal larynx, but there was little fluorescence for IgA, IgM and IgE. Secretory component (SC) synthesis, on the other hand, was found in each serous-type glandular epithelium or acinus from the fourth month on. Our observations suggest that the local immune system by SC, which binds to IgA as SIgA in human laryngeal mucosa, is inherently acquired in the fetal larynx.

Epithelium↗

PubMed1984

The binding of human milk lactoferrin to immunoglobulin A.

It was recognized that in human milk some amounts of lactoferrin (LF) were naturally bound to secretory IgA (sIgA). Since not only secretory component (SC) but also LF was released from sIgA by disulfide bond cleavage, it is conceivable that LF is naturally bound to IgA as well as SC. An in vitro binding test to LF and IgA was performed and the binding was confirmed by the use of an IgA-Sepharose 4B affinity column.

Chromatography, Affinity↗

PubMed1993

Anti pneumococcal antibody activity in nasopharyngeal secretions in healthy adults and children.

The local antibody activity to Streptococcus pneumoniae serotype 6B was measured in nasopharyngeal secretions from 20 healthy adults and 43 children, 1-3 years of age, 14 of whom were healthy and 29 were at risk for developing recurrent episodes of acute otitis media (RAOM) according to the criteria described below. In children, anti pneumococcal IgA and IgG antibody activity was of the same magnitude in both groups. Adults showed significantly higher specific IgA activity. Antibody activity of the IgG isotype was also higher in adults, possibly reflecting the higher serum antibody levels. The children at risk of developing RAOM had significantly higher levels of secretory component (SC) in their nasopharyngeal secretions. Our data suggest that local immunity in the nasopharynx is not fully developed in young children, which might contribute to bacterial survival and colonization in the region.

Acute Disease↗

PubMed1985

Receptor-mediated endocytosis of polymeric IgA and galactosylated serum albumin in rat liver. Evidence for intracellular ligand sorting and identification of distinct endosomal compartments.

Rat polymeric IgA (pIgA) and galactosylated bovine serum albumin (GalBSA), once injected to rats, are avidly taken up by hepatocytes via receptor-mediated endocytosis. Of injected pIgA, 64% was transferred undigested into bile within 3 h, with a peak at 30-45 min. GalBSA was essentially digested in lysosomes. By electron microscopy using ligand-peroxidase conjugates, both ligands were internalized through coated pits/coated vesicles into similar electron-lucent vesicles and tubules. Subsequently, pIgA remained mostly associated with small vesicles clustering around and fusing with bile canaliculi, while GalBSA was predominantly found in large, heterogeneous endocytic structures and in lysosomes. By subcellular fractionation, they were associated at 3 min after injection with structures that similarly sedimented in the P fraction (250 000 - 3 X 10(6) X g X min) and equilibrated at densities of about 1.13 g/ml in sucrose gradients. At 10 min and 20 min, pIgA distribution remained mostly in the P fraction at the same equilibrium density. A minor component of the pIgA distribution was found at the density of lysosomes, but contrary to lysosomal enzymes, its distribution was not affected by Triton WR 1339. In contrast to pIgA, GalBSA was progressively recovered in the L fraction (33 000 - 250 000 X g X min) with organelles equilibrating around 1.11 g/ml, and, by 20-45 min, was found in the ML fraction (10 000 - 250 000 X g X min), around 1.20 g/ml, i.e. in lysosomes. Chloroquine did not reduce the efficiency but delayed the secretion of pIgA into bile. Similarly, it did not affect the uptake of GalBSA but apparently delayed GalBSA transfer along successive populations of host organelles. The low density, GalBSA-containing structures were devoid of proteolytic activity. Anti-secretory components IgG and F(ab')2 were selectively excreted into bile, partially or totally as compounds of lower molecular mass. These antibody fragments probably result from a disulfide reduction activity along the pIgA pathway. In conclusion, our data (a) strongly suggest that pIgA and GalBSA are sorted between 3 min and 10 min after injection in non-lysosomal acidic organelles, (b) identify two successive and physically distinct endosomal populations containing GalBSA, and (c) provide the first evidence for a disulfide reduction activity along the transcytotic pathway of rat hepatocytes.

Animals↗

PubMed1996

Epithelial-myoepithelial carcinoma of the palate.

A case of epithelial-myoepithelial carcinoma (EMC) of the palate in a 72-year-old Japanese man is described. The patient had noticed swelling of the palate commencing about 20 years previously. Histologically, the tumor consisted of a proliferation of double-layered duct-like structures with two distinctive cell types. The inner layer was composed of eosinophilic epithelial cells, while the outer layer was composed of clear cells. Immunohistochemical analysis revealed that reaction products for total keratin were predominantly found in the cytoplasm of the inner epithelial cells, while those for S-100 protein and smooth muscle actin were observed only in the outer cells. Immunoreactive products for secretory component and lysozyme were found in some of the luminal contents and the inner cells of the tumor nests. These findings indicated this tumor to be an EMC of the palate, which had shown no aggressiveness over a twenty-year period prior to surgical excision.

Actins↗

PubMed1987

Production and secretion of immunoglobulins in the gastrointestinal tract.

Two decades ago it was shown that the major immunoglobulin (Ig) present in human secretions is a dimeric IgA covalently bound to an epithelial glycoprotein of about 80 kD, now called the secretory component (SC). Pentameric IgM is likewise actively enriched in most exocrine fluids and is associated with SC, although not in a covalently stabilized complex. Three findings explain the selective translocation of polymeric Ig (pIg) into exocrine fluids: (1) preferential local production; (2) J-chain-expressing capacity of pIg-producing immunocytes; and (3) SC-mediated epithelial transport. Human hepatocytes lack SC and the human liver, therefore, cannot act as an efficient "IgA pump". This is in contrast to the rat liver which shows a remarkable capacity for transport of dimeric IgA from blood into the bile. The J chain of pIg and the epithelial SC represent the "lock and key" in the glandular transport of secretory IgA (SIgA) and SIgM. It has recently been shown that SC is synthesized as a transmembrane protein of about 95 kD and constitutes the actual pIg surface receptor. Complexing between ligand and receptor in the plasma membrane is followed by endocytosis. The completed SIgA and SIgM molecules are then translocated in cytoplasmic vesicles through the epithelial cell to the gland lumen along with an excess of free SC. The main function of SIgA is to exert immune exclusion; that is, by intimate cooperation with innate nonspecific defense factors it decreases penetration of soluble antigens and inhibits epithelial colonization of bacteria and viruses. Especially in selective IgA deficiency, SIgM may exert a similar protective function since its synthesis is markedly increased in the intestinal mucosa. Leakage of IgG into exocrine fluids is enhanced by mucosal irritation. Although IgG should not be considered as a SIg, it may contribute to immune exclusion. This is seen especially in the respiratory tract where IgG is less easily subjected to proteolytic degradation than in the intestinal juice. In contrast, by activating complement, IgG antibodies may at the same time be phlogistic and accelerate mucosal penetration of antigens. IgG may thus contribute to persistent immunopathology in mucosal disease. The same is true for IgE antibodies which may be carried into mucous membranes and secretions by mast cells and cause their degranulation with local histamine release. Traces of IgD may likewise be found in the secretions but without obvious biologic significance. Regulation of secretory immunity takes place both in organized lymphoepithelial structures, such as the Peyer's patches, and adjacent to the glands in the lamina propria.(ABSTRACT TRUNCATED AT 400 WORDS)

Celiac Disease↗

PubMed1980

Studies of the transport of polyclonal IgA antibody from blood to bile in rats.

Bile or thoracic duct lymph, collected from rats 7-9 days after suspensions of B. abortus, S. typhi or SRBC had been injected into the Peyer's patches, contained high titres of specific agglutinins. Samples of these fluids were injected i.v. into unimmunized, syngeneic recipients and the partitioning between blood and bile of the injected antibodies was studied and found to depend on the source and class of the antibody. IgA antibodies from lymph plasma disappeared rapidly from the recipients' blood and half of the dose was recovered in the bile within 2 h of its injection. IgA antibodies which had been collected from bile and so had previously traversed the liver and acquired secretory component, appeared in the recipients' bile much less rapidly so that less than half of the dose entered the bile over a period of 40 h. Passively administered IgG antibodies did not enter the recipients' bile to any significant extent and specific haemolysins never appeared in the bile after either passive or active immunization.

Agglutinins↗

PubMed1990

Immunohistochemical characterization of glomerular IgA deposits in IgA nephropathy.

To characterize the IgA deposits found in glomeruli of IgA nephropathy, frozen sections of renal biopsy specimens from 191 consecutive patients with IgA nephropathy were examined by immunofluorescent microscopy. All 191 specimens were positive for IgA1 in glomeruli. IgA2 was detected in 3 out of these 191 specimens. Both kappa and lambda light chains were also detected in the glomeruli of all specimens. The presence of J chain was represented in 113 specimens after acid-urea pretreatment. Secretory component (SC) was detected in 13 out of the 191 specimens, but not in controls. Both J chain and SC were detected in 2 out of 3 specimens positive for IgA2 but not for IgM. These results suggest that IgA deposited in glomeruli in some patients with IgA nephropathy is perhaps mucosally derived IgA.

Fluorescent Antibody Technique↗

PubMedDate not supplied

Loss of secretory activity in the glands of nasal polyps.

Secretory activity in the glands of the nasal polyps from 15 patients with or without allergic histories was examined by using a direct (anti-IgA) or indirect (anti-SC) immunofluorescent technique. Glands were found in all the examined nasal polyps, but in many, only a few were present. Active secretory process of IgA was observed in the intraepithelial glands of the ciliated, pseudostratified epithelium. Most of the dilated glandular ductules, on the contrary, appeared to be lacking in secretory activity of IgA. Such were commonly filled with mucus materials and their epithelial glandular cells showed no fluorescence for anti-SC, whereas the active IgA secreting cells showed a heavy fluorescence for secretory component (SC) in indirect immunofluorescent studies. Activity of the glandular ductules, therefore, was determined by examining the SC producing activity. In some extracted polyps, SC containing dilated glands were present. These active glands, however, lost the SC producing activity followed by the stasis of mucus flow in the lumen. Thus, when the glands were occupied by mucus materials, stretched and cystic degeneration ensued.

Adolescent↗

PubMedDate not supplied

IgA immunocytes in tonsils.

Dimeric IgA-forming cells were studied by a secretory component (SC) affinity test on 20 palatine and 7 pharyngeal tonils from children. This study also included an investigation on the immunoflurescent localization of IgA immunocytes and IgA and SC deposits. The results showed that IgA immunocytes capable of binding SC in tissue sections are present in both palatine and pharyngeal tonsils. However, the number of cells positive for the SC affinity test was significantly lower than that of IgA immunocytes not binding SC. IgA immunocytes were located mainly in the subepithelial area, medullary portion, and occasionally the intraepithelial layer. SC determinants were detected only in some epithelial cells of the pharyngeal tonsils. The findings of the present study suggest that the pharyngeal tonsils share in the local immunological mucosal resistance regulated by secretory IgA, although its activity might be limited.

Adolescent↗

PubMed1984

Secretory IgA in Schönlein-Henoch purpura.

2 young patients with Schönlein-Henoch purpura were investigated to detect secretory IgA and secretory component (SC) in skin lesions and urine in connection with the upper respiratory and intestinal symptoms at onset. In these cases, laboratory findings revealed relative leukocytosis, hematuria, and proteinuria in urinalysis, but no elevation of serum immunoglobulin levels and ASO titer. In biopsy specimens from purpuric lesions on lower extremities, leukocytoclastic vasculitis was found in the upper dermis histologically. Immunofluorescence showed deposits of IgG and IgA with SC and joining chain and complement at vessel walls in the upper dermis, and SC was deposited at the dermoepidermal junction. An attempt to concentrate urine from the patients revealed precipitin lines of IgG, IgA, and SC by using Ouchterlony's method. These observations suggest that in patients with Schönlein-Henoch purpura circulating immune complexes containing secretory IgA and SC deposits in skin lesions and kidney exist in connection with the initial involvements on the mucous membranes of the respiratory and/or intestinal tracts.

Biopsy↗

PubMed1982

Property and physiological role of biliary secretory IgA in rats.

Secretory IgA (sIgA) and monomeric IgA (mIgA) were purified from normal rat bile, and their role in the gastrointestinal tract was investigated. Biliary sIgA has a molecular weight of approximately 400,000 daltons and a sedimentation constant of 11.7S. Thus, sIgA obtained from rat bile had physicochemical properties similar to those reported for sIgA in other secretions, and probably consists of L-chains, alpha-chains and secretory component. After in vitro incubation with trypsin or intestinal fluid, sIgA remained intact, whereas mIgA was hydrolyzed. Rats challenged repeatedly with dinitrophenylated bovine serum albumin (DNP-BSA) had specific IgA antibody against DNP in the bile and feces as measured by a radioimmunoassay using [3H]-DNP-lysine. Our results demonstrate a possibility that biliary sIgA, not mIgA, has an important role which inhibits the absorption of foreign antigen from intestine.

Animals↗

PubMed1991

Histopathological study of mucosal and submucosal cysts of stomach.

To clarify the characteristics of mucosal and submucosal gastric cysts, five stomal cancers of the remnant stomach, two cancers with a diffuse cystic distribution and three ordinarily resected cancers were used to study mucinous patterns, proliferative cells and humoral defensive factors in the cystic epithelia. Most cysts showed a gastric appearance with relatively dominant ConA III (+) pyloric gland-like features, and were positively stained with high-iron diamine-alcian blue. Although a few cells positive for proliferative cell nuclear antigen (PCNA) were seen in epithelia, cysts generally revealed a low degree of proliferation, less than 2% of epithelial cells being PCNA (+). Cysts were formed from the isthmus or from ordinary glands, and showed an increase of IgA and secretory component in epithelia of the supranuclear, luminal or basolateral region and increased lysozyme (Ly) activity. Some cysts contained cells with strong positivity for Ly which could not be confirmed as Paneth cells by HE staining. Mucosal and submucosal cysts are considered to arise as a reaction to inflammation, and have a tendency to show both gastric and intestinal characteristics.

Aged↗

PubMed1978

[Specific antibodies bound to secretory IgA in the sera of patients with intestinal infections].

Specific IgA and sIgA antibodies were studied in the sera of patients suffering from various intestinal diseases (dysentery, salmonellosis, typhoid fever, chronic typhoid carrier state) and in the sera of healthy persons immunized by parenteral route with typhoid alcohol vaccine. The nature of antibodies was identified in Coombs' test, using monospecific antisera to alpha-chain and to the secretory component. IgA and sIgA antibodies were revealed most frequently in the sera of dysentery patients and of chronic typhoid carriers. No sIgA antibodies were found in the sera of subcutaneously immunized persons. The presence of specific sIgA antibodies in the serum reflects the participation of local immune mechanisms in the formation of systemic immunity in the intestinal infections.

Chronic Disease↗