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)

The relatively unrelated spotted fever group rickettsia Rickettsia rhipicephali conferred on guinea pigs protective immunity against challenge with virulent R. rickettsii. Immunity was conferred at all doses of R. rhipicephali used in the study. Because of the serologic unrelatedness of these two rickettsiae, determined by the use of microimmunofluorescence and other serological assays, further studies were performed to define the nature of the immune response elicited by R. rhipicephali and the characteristics of the rickettsial antigens that evoke cross-reactive antibody responses. Animals immune to R. rhipicephali tested at the time of challenge showed a complete cross-reactive lymphocyte proliferative response to rickettsial antigens prepared from each species. In fact, spleen cells from R. rhipicephali-immune animals responded better to R. rickettsii antigens than to homologous immunizing antigens. Serum samples were obtained from R. rhipicephali-infected animals at various times after infection and tested by the use of Western immunoblot assay for antibodies that were cross-reactive with antigens of R. rickettsii. By 10 days after infection with R. rhipicephali, antibodies to antigens of both species were noted, and by 37 days after infection, sera from immune animals showed strong reactivity to antigens of R. rhipicephali with apparent molecular masses of 107 and 151 kDa. The cross-reactive antibody response to antigens of R. rickettsii was relatively strong and involved predominantly the rOmpB protein and the rickettsial lipopolysaccharide. These findings establish the presence of T-cell-dependent epitopes associated with antigens of R. rhipicephali, which confer protective immunity against challenge with R. rickettsii. Results of Western immunoblot assays support the contention that the R. rickettsii rOmpB surface antigen contains important protective epitopes.
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PMID:Demonstration and partial characterization of antigens of Rickettsia rhipicephali that induce cross-reactive cellular and humoral immune responses to Rickettsia rickettsii. 145 43

Using immunoblots to analyze antigenic relationships among the pathogenic spotted fever and typhus group rickettsiae, I found that the rickettsial lipopolysaccharide (LPS) was a group-specific antigen. All the rickettsiae examined had 135-kDa and 58-kDa protein antigens. The spotted fever rickettsiae and Rickettsia canada had, in addition, 190-kDa protein antigens which were antigenic analogs of previously described protective antigens of R. conorii and R. rickettsii.
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PMID:Antigenic relationships among the rickettsiae of the spotted fever and typhus groups. 191 32

The line blot, a new immunoassay in which antigens are placed on nitrocellulose as narrow lines, was evaluated for its sensitivity and specificity relative to the microimmunofluorescence assay for the diagnosis of Mediterranean spotted fever (MSF). The line blot assay was only slightly less sensitive and less specific than the microimmunofluorescence assay for detection of immunoglobulin M (IgM) or IgG in 100 serum specimens from 42 patients with MSF. No line blot reactions were observed among 50 control serum specimens from febrile patients with other illnesses. The line blot assay was largely group reactive for spotted fever rickettsiae, but 26% of the positive serum specimens also cross-reacted by IgM with Rickettsia typhi. Western immunoblotting was used to characterize the antigenic components recognized by 19 MSF serum specimens. For both IgM and IgG, lipopolysaccharide was the cross-reactive group antigen, whereas the high-molecular-weight species-specific protein antigens (SPAs) were the only reactive proteins. Relative to the other nine rickettsiae, Rickettsia bellii was unique both in exhibiting no SPA reactions and in having a lipopolysaccharide with a predominantly high-molecular-weight distribution. Although most of the 19 MSF serum specimens examined by Western blotting exhibited preferential reactivity to SPAs of two strains of R. conorii and weaker reactions to the other rickettsiae, 2 serum specimens exhibited SPA reactions consistent with typhus infections. In comparison with other assays, the line blot and Western blot immunoassays have advantages which may permit an improvement in the general availability and commercialization of assays for the serodiagnosis of rickettsial infections.
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PMID:Line blot and western blot immunoassays for diagnosis of Mediterranean spotted fever. 250 23

BALB/c mice were inoculated intraperitoneally either once only, or up to four times at weekly intervals, with viable Rickettsia rickettsii, Rickettsia conorii or the Israeli spotted fever group rickettsia. Sera collected one week after the last inoculation were tested for the presence of antibodies reactive with the above organisms by indirect fluorescent antibody testing and Western blot. With repeated inoculations there was a general progressive rise in homologous and heterologous immunofluorescence titers although the increase after the first inoculation was always the greatest. For each rickettsia, the homologous titers were higher than the heterologous titers. Western blots showed that the reactive antibodies were against rickettsial high molecular mass species specific protein antigens and homologous species-specific antibody reactions were detectable earlier than heterologous cross-reacting antibody reactions. Antibodies in mice sera did not react with the group specific lipopolysaccharide-like antigens of the rickettsiae although such reactivity was strong in Western blots with sera from patients suffering from acute Rickettsia conorii infections. Our findings suggest that the intraperitoneal route of inoculation of BALB/c mice can be used for the differentiation of spotted fever group rickettsiae.
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PMID:Species-specific BALB/c mouse antibodies to rickettsiae studied by western blotting. 805 Jul 15

A seroepidemiological survey in coastal Croatia detected antibodies reactive with Rickettsia conorii in 4.2% of sera by immunofluorescence assay and in 5.0% of sera by enzyme immunoassay. Western immunoblotting demonstrated antibodies to the 120-kDa surface protein in all 20 positive serum samples examined and to rickettsial lipopolysaccharide in 3 of these serum samples. Humans in this area are clearly being exposed to spotted fever rickettsiae.
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PMID:Prevalence of antibodies to spotted fever group rickettsiae along the eastern coast of the Adriatic sea. 837 Jul 56

The antigenic reactivity in Western immunoblotting assay of individual Rickettsia conorii components with sera of healthy people living in Salamanca Province, an endemic zone of Mediterranean spotted fever, is evaluated. Polypeptides of molecular weights 100 kDa (92.7%), 135 kDa (75.6%), 160 kDa (70.7%) and 115 kDa (48.8%) were recognized by a higher proportion of sera with indirect immunofluorescent antibody test titers > or = 1:80. Reaction with apparent rickettsial lipopolysaccharide was found in 15 (36.6%) of these samples. The involvement of different rickettsial strains, atypical routes of inoculation, varying content of the inoculum, and host factors may be determinants of the clinical expression of the spotted fever group rickettsial infection in people who produce antibodies reactive with Rickettsia conorii antigens.
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PMID:Antigens of Rickettsia conorii recognized by seropositive healthy people from Salamanca (central-west Spain). 847 2

Astrakhan fever is a new spotted fever group (SFG) rickettsiosis. Sera of patients with Astrakhan fever have been examined by microimmunofluorescence and western immunoblotting to determine the serologic responses to the Astrakhan strain and to R. conorii M-1 strain and the Israelian isolate of SFG rickettsiae. The serologic response to specific rickettsial agent and to Israelian isolate has been found to be similar, but was different of that to R. conorii. Immunoglobulin G (IgG) and IgM antibodies were detected in most sera and were directed against the lipopolysaccharide. Only one of tested sera contained IgG antibodies which also recognized high molecular weight proteins.
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PMID:Serologic response to rickettsial antigens in patients with Astrakhan fever. 854 3

Cross-reactivity between Rickettsia japonica and R. typhi was observed by immunofluorescence tests using sera from patients with Oriental spotted fever (OSF), from whom the causative agent was isolated and identified as R. japonica. Western immunoblotting with these sera revealed that only the 120-kilodalton surface polypeptide, i.e., rickettsial outer membrane protein (rOmp) B, has a common antigenicity with the 105-kilodalton surface polypeptide of R. typhi. In some cases, antibodies specifically reactive with R. typhi were detected in acute-phase sera followed by a significant rise in titers, possibly because of an anamnestic response to a previous infection with an R. typhi-like agent; the sera retained reactivity to R. typhi even after absorption by a homologous strain. A lipopolysaccharide (LPS)-like antigen of R. typhi was found to be reactive with some sera of OSF patients. The ladder bands on Western immunoblot of rickettsial organisms were confirmed to be polysaccharide in nature, which was demonstrated by comparing them with the pattern of silver-stained gel of proteinase K-treated rickettsial specimens after sodium dodecyl sulfate-polyacrylamide gel electrophoresis.
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PMID:Cross-reactivity of Rickettsia japonica and Rickettsia typhi demonstrated by immunofluorescence and Western immunoblotting. 878 54

Based on monosaccharide analysis and 1H- and 13C-NMR spectroscopy, the following structure of the O-specific polysaccharide chain of Proteus vulgaris OX2 lipopolysaccharide (LPS), which defines the O2 specificity of Proteus, was established: [formula: see text] where L-QuiNAc is N-acetyl-L-quinovosamine (2-acetamido-2,6-dideoxy-L-glucose). Various strains of P. vulgaris OX2 used in the Weil-Felix test for serodiagnosis of rickettsiosis (spotted fevers, except for Rocky Mountain spotted fever) were shown to produce LPS with the same O-specific polysaccharide, which differs structurally and serologically from LPS of P. vulgaris OX19 used as antigen for serodiagnosis of typhus and Rocky Mountain spotted fever. O-Acetyl groups present in the polysaccharide are not important for manifesting the immunospecificity. ELISA confirmed that the epitope responsible for the cross-reactivity between sera from patients with Japanese spotted fever and P. vulgaris OX2 cells is located on the P. vulgaris LPS. At the same time, no cross-reaction was observed between rabbit anti-P. vulgaris OX2 antibodies and the spotted fever group (SFG) rickettsial cells. Therefore, human anti-SFG rickettsial antibodies and rabbit anti-P. vulgaris OX2 antibodies may bind to distinct epitopes on P. vulgaris OX2 LPS, and no epitope recognized by rabbit anti-P. vulgaris OX2 antibodies is present on the LPS or any other surface antigen of SFG rickettsiae.
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PMID:Structural and serological studies of the O-antigen of the bacterium Proteus vulgaris OX2 (serogroup O2) used in the Weil-Felix test. 911 24

Rickettsiae are gram-negative, obligate intracellular bacteria which have historically been divided into three groups: the typhus group, the scrub typhus group, and the spotted fever group (SFG). Recently, several new SFG rickettsiae have been characterized, and most of these species are associated with ticks and have, as yet, no known pathogenicity toward humans. Rickettsia massiliae, which is widely distributed in Europe and Africa, is one such rickettsia. In order to investigate the antigenic relationships between R. massiliae and other rickettsial species and to develop a more convenient methodology for identifying R. massiliae, we produced monoclonal antibodies against the type strain (Mtu1T) of R. massiliae by fusing immunized splenocytes with SP2/0-Ag14 myeloma cells. A panel of 16 representatives were selected from the 163 positive hybridomas identified on initial screening, and their secreted monoclonal antibodies were further characterized. The reactivities of these 16 monoclonal antibodies with a large panel of rickettsial species were assessed by the microimmunofluorescence assay. All species of the SFG rickettsiae reacted with the monoclonal antibodies directed against epitopes on lipopolysaccharide, which is the common antigen among the SFG rickettsiae. Some closely related species of the SFG, such as Bar29, "R. aeschlimanni," and R. rhipicephali, showed strong cross-reactivities with the monoclonal antibodies directed against epitopes on the two major high-molecular-mass heat-labile proteins (106 and 120 kDa). In addition, species-specific monoclonal antibodies demonstrated that R. massiliae is antigenically different from other rickettsial species. Moreover, these species-specific monoclonal antibodies were successfully used for identifying R. massiliae in the ticks collected from southern France, and are therefore potentially useful tools in the identification and investigation of R. massiliae in ticks in large-scale field work.
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PMID:Production of monoclonal antibodies against Rickettsia massiliae and their use in antigenic and epidemiological studies. 919 80


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