Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Polyclonal protein HC-IgA complexes (HC-IgA) were isolated from two different serum pools. Their hydrodynamic volumes were found to be slightly greater than that of monomeric IgA but less than that of dimeric IgA. Sodium dodecyl sulphate (SDS)-polyacrylamide gel electrophoresis of reduced and carboxymethylated complexes followed by immunoblotting showed that the complexes contained normal light and heavy Ig chains, and one polypeptide chain with Mr = 90,000, which carried both IgA alpha chain and protein HC epitopes. Enzyme-linked immunosorbent assays (ELISA) demonstrated that the isolated HC-IgA carried about 0.1 and 4%, respectively, of the antibody activities against one carbohydrate antigen (Yersinia enterocolitica serotype 0:3 lipopolysaccharide) and one protein antigen (rabbit IgG, i.e. antigen for rheumatoid factors) of the IgA populations of the two serum pools. HC-IgA with rheumatoid factor activity could also be demonstrated in the unfractionated serum pool. The binding of HC-IgA in the ELISA was not mediated through its protein HC part. The present observations show that HC-IgA carries antibody activities and constitutes a unique class of IgA complexes, since it does not dissociate under denaturating conditions after reduction. It may represent a further biological potential of the humoral immune system.
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PMID:Protein HC-IgA complexes carry antibody activities. 244 67

The regulation of the subclass of immunoglobulin secreted by B cells has been studied in vitro in polyclonal systems using mitogens, such as lipopolysaccharide (LPS), to bypass the requirement for cognate interaction between antigen-specific T and B cells. In these systems, interleukin-(IL)-4 induces the secretion of IgG1 (ref. 1) and IgE (ref. 2); IL-5 enhances the secretion of IgA, and interferon-gamma (IFN-gamma) enhances the secretion of IgG2a (ref. 5). Clones of murine TH cells can be divided into two subsets, TH1 and TH2 (ref. 6). Both subsets synthesize IL-3 and granulocyte-monocyte colony-stimulating factor (GM-CSF), but only TH1 clones produce IL-2, IFN-gamma, and lymphotoxin (LT) and TH2 clones produce IL-4 and IL-5 (ref. 7). We have examined the role of clones of antigen-specific TH1 and TH2 cells in the regulation of the subclasses of IgG antibody secreted by antigen-specific B cells. Our results show that both types of TH cells induce the secretion of IgM and IgG3, whereas clones of TH1 and TH2 cells specifically induce antigen-specific B cells to secrete IgG2a and IgG1, respectively. We also demonstrate that regulation of commitment to the secretion of a particular IgG isotype occurs in two distinct stages: cognate interaction between T and B cells and interaction between T-cell-derived lymphokines and B cells.
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PMID:Regulation of antibody isotype secretion by subsets of antigen-specific helper T cells. 245 66

Female guinea pigs which had been infected genitally with the agent of guinea pig inclusion conjunctivitis were challenged at various times after infection with fresh inocula to determine the duration of immunity resulting from the primary infection. At 30 days after infection, most guinea pigs were resistant to reinfection, as indicated by the inability to isolate chlamydiae from cervical swabs. However, at 77, 155, and 294 days, all animals became reinfected, although the course of the infection was abbreviated and of lower intensity. When various immune parameters were examined, a decrease in antibodies in both serum (immunoglobulin G [( IgG]) and genital secretions (IgA, IgG) was observed after 30 days. A decrease in antibodies to the major outer membrane protein and an 84K component was noted in serum. In genital secretions, IgA antibodies to all major chlamydial components declined markedly after 30 days. Cell-mediated immunity as measured by proliferation of peripheral blood lymphocytes to guinea pig inclusion conjunctivitis antigen also was at a peak response 30 days after infection and decreased thereafter. Thus, loss of complete immunity could not be associated with a particular immune parameter. When genital secretions were examined 14 days after the challenge infection, IgA antibody levels to the lipopolysaccharide and 61K protein components had increased in intensity, whereas other antibodies were relatively low. In addition, complete immunity to a third infection was not increased in duration when animals had recovered from two previous genital infections.
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PMID:Susceptibility to reinfection after a primary chlamydial genital infection. 245 53

Several studies have indicated that thymus-independent (TI) antigens, unlike their thymus-dependent (TD) counterparts, are poor at generating memory antibody responses (Immunol. Today 1981. 3:217). In contrast to this view, the present report shows that the TI type 1 (TI-1) antigen, 2,4,6-trinitrophenyl-lipopolysaccharide (TNP-LPS), elicits good secondary responses in rats. These secondary antibody responses are not only greater in magnitude than the primary responses, but display a different pattern of Ig classes with more IgG and IgA antibodies produced. In transfer experiments between congenic strains of rats which differ in their kappa light chain Ig allotype, it is shown that this memory is attributable to persistent B cell clones. The TI-2 antigen, 2,4-dinitrophenyl-hydroxyethyl starch (DNP-HES), given alone did not elicit B cell memory. However, when DNP-HES is presented to the immune system in association with LPS, the pattern of the anti-DNP response is similar to that elicited by TNP-LPS. The capacity to generate TI memory is associated with the appearance of hapten-specific B cells in the marginal zones of the spleen. Hapten-binding cells were induced in the marginal zones following immunization with TNP-LPS, but not by DNP-HES. However, concurrent immunization with DNP-HES and LPS which were not covalently linked was found to induce DNP-binding cells in the marginal zone. There is complete correlation between the appearance of hapten-binding memory B cells in the marginal zone and the capacity of these antigens to induce secondary responses.
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PMID:B cell memory to thymus-independent antigens type 1 and type 2: the role of lipopolysaccharide in B memory induction. 245 43

Immunoglobulin heavy-chain switching is effected by a DNA recombination event that replaces the C mu gene with one of the other heavy-chain constant-region (CH) genes located 3' to the C mu gene. How the specificity of this event is controlled is unknown. However, it has been shown that IgM+ cells capable of switching to specific isotypes have the corresponding unrearranged CH genes in an accessible or active chromatin state, as demonstrated by the fact that these specific CH genes are hypomethylated and are transcriptionally active. We now report that the RNAs transcribed from specific unrearranged CH genes are induced prior to switching under conditions that promote switching to these specific CH genes. For example, we find that bacterial lipopolysaccharide, which induces the IgM+ cell line I.29 mu to switch to IgA, induces transcripts from the germ-line C alpha gene(s) in I.29 mu cells prior to switch recombination. Two preparations of T-cell lymphokines (recombinant interleukin 4 and supernatant from the T-cell line 2.19, which contains interleukins 4 and 5) that promote switching to specific isotypes by lipopolysaccharide-treated spleen cells induce transcripts from the corresponding germ-line CH genes prior to expression of the new isotypes. For example, interleukin 4, which appears to be necessary for switching to IgE in vitro and in vivo, induces within 2 days large increases in germ-line C epsilon transcripts in lipopolysaccharide-treated spleen cells and in I.29 mu cells. The most straightforward interpretation of our data is that these lymphokines direct switching to specific isotypes by activating specific CH genes, making them accessible to the putative switch recombinase.
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PMID:Immunoglobulin heavy-chain switching may be directed by prior induction of transcripts from constant-region genes. 245 14

Previous studies have shown that cholera, as well as protective immunity against infection with Vibrio cholerae, can be induced in the rabbit. This protection is long-lasting (up to 30 months) and is characterized on challenge by rapid, symptom-free disappearance of V. cholerae from the intestine; we therefore believe this to be vibriocidal protection. In this study, we analysed the humoral and secretory immune response against various subcellular V. cholerae components in vibriocidally protected, non-vibriocidally protected, and unprotected animals. Only vibriocidal protection was found to be associated with high levels of biliary IgA directed against lipopolysaccharide O antigen. We did not find such a correlation between either type of protection and response in serum. Therefore, anti-lipopolysaccharide antibodies are essential in protection against experimental infection with V. cholerae.
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PMID:Immunoglobulins in bile and serum of the rabbit associated with protection after Vibrio cholerae infection and vaccination. 246 53

The experiment was made on 16 monkeys (rhesus macaques). Only 1 out of 12 monkeys immunized with S. sonnei ribosomal vaccine and all 4 control monkeys fell ill as the result of oral challenge with S. sonnei virulent strain. The immunized monkeys stopped excreting Shigellae earlier than the control monkeys. Antibody to lipopolysaccharide (LPS) in the serum and saliva of the monkeys were studied in the enzyme immunoassay with monospecific antibodies to human IgA, IgG and IgM. A single injection of the ribosomal vaccine in a dose of 600 micrograms was shown to lead to a considerable increase in the levels of IgA, IgG and IgM antibodies to LPS in saliva. In parenteral immunization with the ribosomal vaccine the stimulation of secretory IgA system is similar to that resulting from oral challenge with Shigella virulent strain introduced in a dose of 50 X 10(9) microbial cells. No difference in the response of monkeys to primary and booster immunization was noted.
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PMID:[Stimulation of the secretory IgA system in monkeys by parenteral immunization with a ribosomal Sonne dysentery vaccine]. 246 72

Eight lactating and seven non-lactating female rats were immunized in Peyer's patches (Pp) with Escherichia coli 06 carrying type 1 pili. Eight days later the thoracic duct was drained and bile was collected at the same time. During the lymph drainage in the lactating rats, the biliary IgA anti-pili antibodies decreased less than the anti-lipopolysaccharide (LPS) antibodies. The non-lactating rats showed only a very small difference in decrease between the anti-pili and the anti-LPS antibodies. Transfer of mesenteric lymph node cells from male donor rats immunized with the E. coli strain to syngeneic male recipients resulted in the appearance of both IgA anti-pili and anti-LPS antibodies in the bile. This is at variance with the results seen in lactating rats, where only biliary IgA anti-LPS is seen after similar cell transfer. In conclusion, the study shows that in lactating rats a larger proportion of biliary IgA anti-pili antibodies than anti-LPS antibodies is derived from extraintestinal sites, such as the mammary glands or the liver. Thus, this study confirms that the nature of the antigen influences the transfer of the secretory antibody response to different secretions.
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PMID:Different origins of IgA antibodies with various antigen specificities appearing in rat bile. 246 62

A panel of 14 monoclonal antibodies with specificity for the O-antigenic polysaccharide chain of the lipopolysaccharide of the cell envelope of Salmonella typhimurium was established. The specificity of each antibody clone was determined against a set of Salmonella saccharide antigens, natural and synthetic, in passive hemagglutination and enzyme immunoassays. The monoclonal antibodies could be classified into at least five different groups: (i) O4 epitope specific, (ii) O4,12 specific, (iii) O4,12(2) specific, (iv) O5 specific, and (v) O12 specific. These specificities correspond to different structural and conformational domains of the polysaccharide chain, and often extend over more than one repeating unit (tetrasaccharide) of the polymer. The passive protection afforded by these antibodies was estimated in an experimental mouse typhoid model using S. typhimurium SH2201 for intraperitoneal challenge. Monoclonal antibodies of the IgG3 isotype were available for four of the epitope groups and were protective in the following order of activity O4 greater than O4,12 greater than O4,12(2) greater than or equal to O12. The difference between O4 and 012 antibodies was greater than 2500 fold in protective activity. Antibodies of the IgM class were highly protective irrespective of being of the O4,12 or O12 epitope specificity. Two IgA antibodies with O5 epitope specificity were not protective. The results show that both isotype and epitope specificity can be of importance for the protective ability of antibodies generated by the host.
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PMID:Role of monoclonal O-antigen antibody epitope specificity and isotype in protection against experimental mouse typhoid. 246 61

The class-specific antibody response was measured in sequential serum samples from 17 patients after natural bacteremic infection with gram-negative bacilli. There was a five- to sevenfold mean increase over preexisting antibody in levels of IgG (range, less than 1-to 88-fold), IgA (1- to 83-fold), and IgM (less than 1- to 58-fold) antibody to homologous lipopolysaccharide (LPS) in 16 of these patients. In contrast, there was only a two- to threefold mean increase (range, less than 1- to 78-fold) in about half of the patients who had a detectable antibody response to J5 core determinants and in the third who responded to Re core determinants (range, 1- to 20-fold). All but one of the infective strains of bacteria were smooth on analysis with SDS-PAGE and with rough-specific phages. Humans infected with bacteria that had a rough LPS phenotype, however, did elicit antibody similar to that induced in rabbits after immunization with J5 vaccine. Thus, the human antibody response to natural infection with gram-negative bacilli appears to be directed primarily at homologous, strain-specific epitopes, and the response to the epitopes of LPS core antigens is not against widely shared determinants.
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PMID:The human antibody response during natural bacteremic infection with gram-negative bacilli against lipopolysaccharide core determinants. 247 16


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