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PubMed1978

Concept of the local and common mucosal immune response.

The available information concerning the origin of IgA-producing plasma cells and the spectrum of IgA-associated antibodies found in external secretions provide arguments that support two pathways of stimulation for a secretory humoral immune response. In addition to an explicitly local immune response induced by a topical antigen application, a second mechanism of induction operating through the sensitization of GALT, and possibly BALT, emerges. The latter pathway of stimulation leads to the appearance of specific IgA-associated antibodies in secretions of mammary, salivary, and lacrymal glands (and perhaps other sites), all of which suggests the existence of a common mucosal secretory system. Not yet explained are the mechanisms involved in the homing to secretory glands of cells sensitized in the remote lymphoid tissues (GALT and BALT), the differentiation patterns of these cells, and the regulation of selective IgA expression.

Animals↗
PubMed1978

Molecular-cellular interactions in the secretory IgA system.

1) SC receptors were not detected on the surface of human PBL before or after PWM stimulation or on the surface of established lymphoblastoid cell lines. 2) SC binding was detected in the cytoplasm of differentiated lymphoid cells. The majority of the SC-binding cells contained intracellular IgA. 3) The binding of polymeric IgA to the surface of human epithelial cells (colonic carcinoma HT-29) was dependent on the presence of SC. 4) These findings indicate that SC is a receptor and possible transport protein for polymeric immunoglobulins, but that it is not directly involved in the homing of the IgA precursor cells to secretory tissues.

Binding Sites↗
PubMed1978

Salivary IgA antibodies to antigens from Streptococcus mutans in human dental caries.

1) Subjects of low caries experience (DMF 7) had significantly lower IgA antibody titers to antigens from S. mutans serotype c than subjects of high caries experience (DMF 13). 2) Subjects with carious lesions and a high DMF had significantly lower salivary antibody titers than subjects without carious lesions. 3) Sequential studies revealed that in the absence of caries salivary antibody titers decreased over a 9 month period. 4) Treatment of caries was associated with a rise in salivary IgA antibodies. No significant changes were associated with the development of caries. 5) No relationship with caries experience was found with antibodies to S. mutans BHT (serotype b), S. sanguis OMZ-9 or S. mitis CHT. 6) The results do not support the hypothesis that salivary antibodies in man play a role in protection against caries.

Antibodies, Bacterial↗
PubMed1985

[Immunoenzyme demonstration of isoantigens A, B and H in kidney tissue changed by putrefaction].

In contrast to blood serology, which usually fails in specimens more than a few days old, immunohistochemistry (PAP technique) provided reliable information on the blood group (ABO) and, in most cases, also the secretor character of 23 kidney specimens stored for months at room temperature. Better results were obtained with monoclonal antibodies than with human sera. In the late stages of decomposition, blood group diagnosis is based on the more decomposition-resistant antigens of the collecting tubular epithelium (in secretors) and the endothelia of the arteriolae medullares rectae and not on the identification of erythrocytic antigens. In addition, a decomposition-resistant epithelial antigen in the distal convoluted tubules (Tc II) is unmasked by autolysis or heterolysis. "Blood group" antigens were frequently detected in bacteria and fungi. These antigens, however, were clearly distinguishable from blood group characters of the tissue. A transient, weak, false-positive reaction with monoclonal anti-B appeared in decomposed Tc II epithelia.

ABO Blood-Group System↗
PubMed1984

Lectin binding of surface epithelia and concomitant glands of gallbladder and biliary ducts in the guinea pig.

Complex carbohydrate components of secretory granules and the glycocalix were analysed in surface epithelia, endoepithelial glands and exoepithelial tubuloalveolar glands of the biliary-ductular system (guinea pig). Brunner glands and pyloric glands were studied for comparison. The columnar epithelial cells of the gallbladder and biliary ducts displayed a well-developed PAS-positive apical glycocalix. These materials strongly bound Ricinus communis A I, Ulex europaeus I, Lotus tetragonolobus A and wheat-germ-A lectins. With the exception of Lotus A lectin which did not bind at all, the same lectins stained the basolateral cell surface. The secretory granules in the supranuclear regions of surface epithelia and in the exoepithelial glands strongly bound Ricinus A I, Ulex europaeus I, wheat-germ-A and Helix pomatia lectins. Concanavalin A was less intensively bound by the secretions of tubuloalveolar glands than by the secretory granules in surface epithelia. The luminal and basolateral cell surfaces of glandular cells in the exoepithelial glands were stained by the same spectrum of lectins as were the columnar cells of surface epithelia, but the staining was less distinct. In the guinea pig, the lectin-binding patterns of tubuloalveolar glands in the biliary ducts closely resembled those of Brunner glands and pyloric glands. The secretions of the tubuloalveolar glands were different from the secretion of surface epithelia, as they bound Concanavalin A less intensively.

Animals↗
PubMed1990

The role of IgA in local immune protection.

The secretions that bathe the mucosal surfaces contain an array of host defense factors that differ in composition and concentration from those in the serum. Most of the immunoglobulins in external secretions exist as polymers of the basic four-chain Ig units; IgA is the major isotype. The unique cellular pathway that results in the production of IgA by plasma cells at the local mucosal level is linked by proximity to an epithelial mechanism that selectively transports polymeric IgA (as well as IgM) into the secretions and converts them into secretory immunoglobulins (SIgA and SIgM). Because of their unique structure, these secretory immunoglobulins are well adapted to function, along with the other secretory immune factors, in the external secretions. The rate of SIgA production may also be regulated at the level of the epithelial cell.

Animals↗
PubMed1985

Defence of mucous membranes by antibodies, receptor analogues and non-specific host factors.

Most infections reach man via the mucosal membranes, and more than half of the lymphoid system is found in connection with mucosae. The major antibodies found on mucous membranes are secretory IgA, which function primarily by binding microorganisms and thereby preventing their contact with the host tissues. The optimal mode of immunization to obtain a secretory IgA response is not well defined. Repeated mucosal exposure with antigen may result in oral tolerance, with decreasing circulating antibodies but a remaining secretory IgA response. The secretory IgA response is usually short-lived and can be difficult to boost. IgM as well as IgG antibodies may add to host defence at the mucosal level, but when engaged, they usually induce inflammation in host tissues. Analogues to bacterial receptors on mucosal epithelium may be present in exocrine secretions such as human milk. During an attack on the host, it is possible that such receptor analogues may aid in the prevention of attachment of bacteria to mucous membranes used as an initial site. A number of non-specific host factors support mucosal defence. One of them is lactoferrin. Lactoferrin deficiency seems to result in recurrent bacterial infections, suggesting its importance in normal host defence.

Antibody Formation↗
PubMedDate not supplied

Mucin histochemistry of submandibular and parotid salivary glands of man: light and electron microscopy.

Light-microscopy showed parotid serous acinar cells to contain neutral mucin, serous and mucous acinar cells of submandibular gland and intercalary ductal cells of both glands to contain acid and neutral mucins, and cells of striated ducts and excretory ducts to contain neutral mucin. Mucins were demonstrated ultrastructurally in a portion of the components of secretory granules of acinar cells and intercalary ductal cells, and in secretory granules of striated and excretory ductal cells. The mucins were all stained by techniques that reveal 1,2-glycols. Secretory granules of submandibular mucous and serous acinar cells and intercalary ductal cells were stained variably by the low iron-diamine technique for acid mucin, and those of mucous acinar cells by the high iron-diamine technique for sulphomucins mucin and possibly consisted of protein. The results suggest that one type of cell may be able to produce a range of secretory products and to package them variously into secretory granules.

Histocytochemistry↗