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Query: UMLS:C0023241 (Legionella)
 6,990 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Immunization of BALB/c mice with Rickettsia prowazekii antigens, Bordetella pertussis toxin and Legionella pneumophila cytolysin induces the synthesis of IgM autoantibodies of different specificity. Among monoclonal antibodies, multispecific antibodies with a wide reactivity spectrum have been found to make up high percentage (30-80%). Monoclonal antibodies interact with different bacterial antigens and tissue substances. A hypothesis has been put forward that normally the injection of the antigen is followed by the appearance of antigen-nonspecific "immunological noise", including the synthesis of both tissue-specific and multispecific autoantibodies. Such antigen nonspecific "immunological noise" must have a certain threshold level which can be determined with the use of hybridoma techniques. This problem is particularly topical for bacterial antigens, as many of them are used in the development of vaccinal preparations, which may lead to an increase in the synthesis of autoantibodies and induce different autoimmune disturbances in the body.
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PMID:[Multispecific monoclonal antibodies]. 175 27

A panel of mAb (IgG1, IgG3, IgM) against Legionella pneumophila cytolysin (CL)-protease of 37 kDa was obtained. Subtyping of L. pneumophila strains of serogroup 1 by using mAb against CL (mAb-CL) was carried out. The results of comparative analysis of the specificity of mAb-CL and the panel of mAb kindly provided by Dr. J. M. Barbaree (Centers for Disease Control, Atlanta, GA) allowed us to recommend mAb-CL to be used as a diagnostic tool to reveal the pathogenicity of L. pneumophila strains of serogroup 1. Hybridomas were also raised in a syngenic system which produced anti-idiotypic mAb (mAb2) against anti-CL mAb B6/1. The Ab2 belonged to Ab2 gamma type: 1) Ab2 reacted with B6/1 Id only, 2) Ab2 inhibited the interaction of B6/1 Ab1 with CL, and 3) CL inhibited the reaction of Ab2 with Ab1. The use of Ab2 allowed us to show that B6/1 Id is expressed in 4 to 32% of serum antibodies during the primary and secondary immune responses of BALB/c mice to CL. Ab2 induced the production of anti-anti-idiotypic antibodies (Ab3) in BALB/c mice, and some of them reacted with CL. Thus, we have demonstrated the possibility of inducing an antibody response to CL (one of the main L. pneumophila pathogenic factors) in intact syngenic mice with anti-idiotypic antibodies.
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PMID:Induction of the immune response to Legionella pneumophila cytolysin by monoclonal anti-idiotypic antibodies. 189 Mar 9

In the process of protein kinase reaction carried out in the mixture consisting of tris-HCl buffer, EDTA, MgCl2, gamma-32P-ATP and the cytoplasmic fraction of rabbit pulmonary cells the phosphorylation of proteins with molecular weights of 150 and 55 kD took place. The addition of L. pneumophila culture fluid to the reaction mixture resulted in the splitting of phosphorylated proteins with the formation of the component having a molecular weight of 45 kD. These disturbances in protein kinase reaction were found to occur due to the involvement of Legionella cytoplasm, a previously characterized protein with a molecular weight of 37 kD, into the process. In this connection, the participation of cytolysin in the pathogenesis of Legionella infection may also be considered from the viewpoint of the effect produced by cytolysin on the regulatory processes affecting the metabolism of target cells.
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PMID:[The splitting of the acceptor proteins of the protein kinase system in eukaryotic cells by Legionella cytolysin]. 195 Feb 77

Endogenous phosphorylation of specific proteins in eukaryotic cells is one of the main mechanisms controlling intracellular metabolic processes. It is proposed that microorganisms multiplying intracellularly possess ways of changing cellular metabolism to benefit their survival. The detection and partial purification of a phosphokinase system in pulmonary cells with acceptor proteins of molecular masses 150 and 55 kDa is reported. It is also shown that the bacterium Legionella pneumophila, a facultative intracellular parasite, secretes a toxic protein, cytolysin, that cleaves the 55 kDa component to produce a 45 kDa protein and probably hydrolyzes the 150 kDa component completely. Thus far, the significance of cytolysin in the pathogenesis of legionellosis has been restricted to its direct necrotic action. This product may, however, also act as a regulator of metabolic processes in the host cells by influencing their protein kinase activity. The findings reported may aid our understanding of mechanisms of intracellular parasitism and the survival strategy of pathogenic bacteria.
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PMID:Action of Legionella cytolysin on components of the phosphokinase system of eukaryotic cells. 213 66

Immunogenic properties of cytolysin were studied in experiments on guinea pigs. Preliminary immunization with cytolysin led to the suppression of response to ConA in lymphocytes not adhering to nylon wool and to the stimulation of response to Legionella antigens in lymphocytes adhering to nylon wool. For a month after infection with L. pneumophila the suppression of the proliferative activity of lymphocytes in the spleen of the immunized animals in response to ConA and Legionella antigens was observed, while in the lungs transitory suppression of response to ConA and Legionella antigens was followed by the restoration and then stimulation of proliferation in response to T-cell mitogen and specific antigens. The data obtained in these experiments indicate the capacity of cytolysin for modulating the development of immune response.
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PMID:[The immunologic properties of Legionella cytolysin]. 225 6

A molecular DNA probe has been obtained on the basis of recombinant plasmid pNIG carrying the Legionella cytolysin gene. The use of this probe for the identification of different Legionella species and other microorganisms has shown that it may serve as the species-specific marker of L. pneumophila. The probe has been used for the identification of new Legionella-like strains isolated from the environment.
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PMID:[The use of a molecular DNA probe based on the cloned cytolysin gene for the identification of Legionella]. 233 Jul 75

A fragment of the gene for cytolysin has been cloned. The product of the gene has been earlier identified as an immunoserological marker of Legionella pneumophila. Clones were selected by immunodetection of cytolysin gene product expression. An EcoRI 3.8 kb fragment of the genomic DNA from Legionella pneumophila strain Philadelphia-1 was used as a DNA probe that hybridized with the bacterial colonies of 20 Legionella pneumophila strains but not with the colonies of 10 other Legionella species or 8 other bacterial genera. The cloned fragment has been shown to be unique for Legionella pneumophila. The region of homology is suggested to be longer than a possible dimension of the cytolysin gene.
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PMID:[Specific DNA probe for detecting Legionella pneumophila]. 238 40

The protective properties of Legionella antigenic preparations were studied on guinea pigs with experimental Legionella infection. Preliminary immunization of guinea pigs with serotypic antigen, cytolysin, as well as live or formalin-treated Legionella cells, did not protect the animals from the subsequent aerogenic infection with 10(5) colony-forming units of virulent L. pneumophila. Immunization with the main outer membrane protein ensured the survival of 70% of the animals and inhibited the proliferation of the infective agent in the lungs of guinea pigs subjected to aerogenic infection with 10(5) colony-forming units of virulent L. pneumophila. The data obtained in this study indicate that the main outer membrane protein of L. pneumophila is capable of stimulating protective immunity.
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PMID:[The protective properties of different Legionella antigens in experimental Legionella infection]. 238 5

Coagglutination test (CoaT), radioimmunoassay (RIA) and ELISA were used for detection of cytolysin produced by L. pneumophila. The sensitivity of RIA was 100 ng/ml, CoaT--10-20 ng/ml, ELISA--1 ng/ml. To determine cytolysin production among various strains and species of Legionella, the authors studied bacterial ultrasonic lysates. All 11 strains of L. pneumophila tested were cytolysin-positive. L. longbeachae, L. bozemanii and L. dumoffii strains failed to produce cytolysin. The authors believe that an antigen of cytolysin can be used for identification of L. pneumophila.
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PMID:[Cytolysin as an immunoserological marker of Legionella pneumophila]. 245

In recent years, tremendous progress has been made in unraveling the elegant mechanisms by which intracellular pathogens invade host cells and establish intracellular infections. By contrast, our knowledge of the mechanisms of host cell cytolysis and the egress of intracellular pathogens is still in its infancy. Temporal pore-formation-mediated lysis of the host and exit by Legionella pneumophila and Leishmania could provide a new model of egress for other intracellular pathogens, many of which exhibit pore-forming or cytolysin activity
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PMID:How does Legionella pneumophila exit the host cell? 1208 52


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