ABSTRACT
Group B streptococcal (GBS) gene encoding the putative lipoprotein and adherence factor ScaAB was cloned and expressed in E. coli. Recombinant ScaAB protein was isolated. Signal sequence of ScaAB was found to be cleaved in the E. coli host. ScaAB recombinant protein was immunogenic in mice and antibodies against this protein were discovered in mice sera after GBS infection. The perspectives of the use of ScaAB protein in GBS vaccine are discussed.
Subject(s)
Bacterial Proteins/immunology , Membrane Proteins/immunology , Recombinant Proteins/immunology , Streptococcal Infections/prevention & control , Streptococcus agalactiae/immunology , Amino Acid Sequence , Animals , Antibodies, Bacterial/blood , Bacterial Adhesion , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Immunization , Membrane Proteins/chemistry , Membrane Proteins/genetics , Membrane Proteins/metabolism , Mice , Molecular Sequence Data , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Streptococcal Infections/microbiology , Streptococcal Infections/mortality , Streptococcus agalactiae/isolation & purification , Streptococcus agalactiae/pathogenicitySubject(s)
Antibodies, Viral/biosynthesis , Immunoglobulin G/biosynthesis , Influenza A virus , Orthomyxoviridae Infections/complications , Orthomyxoviridae Infections/immunology , Streptococcal Infections/complications , Streptococcal Infections/immunology , Streptococcus agalactiae , Animals , Antibodies, Viral/blood , Antibody-Producing Cells/immunology , Immunoglobulin G/blood , Influenza A virus/immunology , Mice , Mice, Inbred C57BL , Mice, Inbred CBA , Spleen/immunology , Time FactorsABSTRACT
Eighty-nine fosfomycin-resistant mutants of group A and B streptococci were isolated. The mutants differed essentially from the parent strains in cell-wall characteristics, such as morphology of cocci and chains, sensitivity to detergents and hydrophobic properties. At the same time, the recipient activity of the investigated mutants was not changed. It is supposed that resistance of mutants to fosfomycin is connected with a transport block of glycerol 3-phosphate--important lipoteichoic acid (LTA) structural component. Fosr mutants can be useful for experimental examination of Beachey's hypothesis about the importance of LTA or its complex with the M protein for adhesion.
Subject(s)
Fosfomycin/pharmacology , Streptococcus/isolation & purification , Drug Resistance, Microbial , Mutation , Streptococcus/drug effectsABSTRACT
Adherence of three strains of group A streptococci and their fosfomycin-resistant mutants to HEp-2 tissue culture cells was compared with some cell-surface characteristics, i.e. ultrastructure and hydrophobicity. Among Fosr mutants, both well-adhering and weakly adhering mutants were found. Clonal analysis of the mutants proved their greater stability in the adherence. Well-adhering parent strains of streptococci and Fosr mutants exhibited surface fibrillae in contrast to weakly adhering Fosr mutants which were devoid of fibrillae or contined fibrillae of lower electron density. Decrease of adherence of Fosr mutants of two strains was accompanied by a decrease of their hydrophobicity.
Subject(s)
Fosfomycin/pharmacology , Streptococcus/ultrastructure , Cell Adhesion , Cells, Cultured , Drug Resistance, Microbial , Streptococcus/drug effectsABSTRACT
In vitro tests for adherence to human vaginal and pharyngeal epithelial cells were used to study the problem of tissue-specific tropism in group B streptococci (GBS). Twenty-two vaginal or pharyngeal clinical isolates of GBS (serotypes Ia, Ib, II, and III) were used. No significant differences in adherence to vaginal and pharyngeal epithelial cells were found between GBS from both sources: statistical analysis furnished no evidence for tissue-specific tropism. Serotype III vaginal GBS adhered better to vaginal and pharyngeal epithelial cells than did serotype III GBS strains isolated from the pharynx. However, pronounced differences in the level of adherence were found among strains of the same serotypes and from the same sources. Thus, the results obtained suggest that differences in adherence may rather be strain-dependent that type-dependent.
Subject(s)
Pharynx/microbiology , Streptococcus agalactiae/physiology , Vagina/microbiology , Bacterial Adhesion , Epithelium/microbiology , Female , Humans , Streptococcus agalactiae/isolation & purificationABSTRACT
The adherence of group B streptococci (GBS) of serotypes Ia, II and III to human vaginal cells was studied in vitro. The adherence was not dependent on the viability of bacteria; killing of GBS by UV irradiation or glutaraldehyde treatment did not inhibit the adherence. Killing of GBS by heating to 56 degrees C for 1 h led to a pronounced decrease of adherence, demonstrating the thermosensitivity of the GBS structures involved. The protein nature of these structures was proved by a significant reduction of adherence after pretreatment of GBS with trypsin or pepsin. Pretreatment of GBS with sialidase had no influence on the adherence. Such a pretreatment of vaginal cells caused an increase of adherence showing that the receptors on epithelial cells may be partly masked by sialic acid.
Subject(s)
Bacterial Adhesion , Streptococcus agalactiae/pathogenicity , Vagina/microbiology , Bacterial Adhesion/drug effects , Bacterial Adhesion/radiation effects , Female , Glutaral/pharmacology , Hot Temperature , Humans , Neuraminidase/pharmacology , Pepsin A/pharmacology , Trypsin/pharmacology , Ultraviolet RaysABSTRACT
Submicroscopic aspects of the adherence of Group A streptococci to HEp-2 cells and the time sequence of their further interaction with these cells were studied. The M+ variant of streptococci, characterized by the presence of filamentous protrusions on the cell wall, displayed a high capacity for adherence, in contrast to the M- variant of the same strain, where adherence was low. The first stage of the interaction between M+ variant of Group A streptococci and HEp-2 cells was adherence of the filamentous protrusions of the bacterial cell wall to host cell cytoplasmic membrane; this was followed by closer contact of the streptococcus cell wall with HEp-2 cell surface. Continuing incubation led to the development of invaginations in the cytoplasmic membranes of HEp-2 cells, into which streptococci gradually penetrated. Ingestion of streptococci into the forming pseudovacuoles of the host cell was accompanied by bacterial cell division, culminating in total disintegration of the host cell and release of the streptococci into the medium. At all stages of the interaction there was a pronounced tendency to form multiple contacts between the surface structures of the streptococcus cell and the membrane structures of the animal cell being attacked.
Subject(s)
Cells, Cultured/microbiology , Streptococcus pyogenes/physiology , Cell Division , Cell Line , Cell Membrane/microbiology , Cell Membrane/ultrastructure , Humans , Kinetics , Streptococcus pyogenes/ultrastructure , Vacuoles/microbiologyABSTRACT
Using the HEp-2 cell line system the factors and mechanisms of group A Streptococcus adherence had been studied. It was shown that high adherence was chiefly found in strains showing attributes of virulence (presence of M protein, growth in human blood, lethality for mice). The data supplied by experiments with pepsin and LTA suggest that there exist at least two mechanisms of adherence.
