Isolation of non-type-specific protein antigens of Streptococcus group B

Hydrochloride extracts obtained from group B streptococcal strains of different serotypes have proved to be the source of type-nonspecific protein antigens, precipitated with ethanol and studied by gel chromatography and spectrophotometric scanning in ultraviolet rays. Thus, 2 or 3 antigens, one of them found to be common for streptococci of groups A, B and G, as well as the admixture of group-specific polysaccharide, have been detected. In extracts obtained from group B streptococcal strains of different serotypes a common protein antigen, specific only for group B, has been detected. The suitability of gel chromatography with the use Toyopearl gel HW-55F for the preparative isolation of the specific fraction of protein type-nonspecific antigen with a view to the subsequent study of immune response to group B streptococci has been shown.     

The effect of immunization with Streptococcus group A on the development of delayed hypersensitivity to BCG antigens in mice of different strains]

Antibodies to group A streptococcal polysaccharide (A-PS) have been shown to appear within three weeks after the injection of group A streptococcus culture, heat-killed and treated with pepsin (A-STP), in the blood of not only BALB/c mice, but also CBA mice. As revealed in this study, in BALB/c mice antibodies are mainly active against the group-specific antigenic determinant (AD) of A-PS and in CBA mice, against the rhamnose AD of A-PS, common for streptococci of different groups. This study has revealed that the appearance of antibodies to the rhamnose AD of A-PS in the blood of CBA mice inhibits antigen-specific cytotoxicity, appearing with the development of delayed hypersensitivity to BCG antigens. This effect is not linked with the immunization of the animals with high doses of streptococci. Experiments have shown that the in vitro transfer of the inhibition of antigen-specific cytotoxicity to lymph node cells of normal BCG-sensitized animals may be carried out with lymph node cells of CBA mice, immunized with A-STP and having antibodies to the rhamnose AD of A-PS, but not with the serum containing these antibodies. The mechanisms of this effect are discussed.     

Monoclonal antibodies cross-reacting with fibroblasts of interstitial connective tissue of the myocardium and cell wall protein antigens of group A Streptococcus

Monoclonal antibodies (MCA) B6/5 and C5/3 were obtained after immunization of BALB/c mice with the protein non-type-specific antigens (NTSA) of streptococcal group A cell wall. MCA B6/5 in the indirect immunofluorescence react with human and animal interstitial connective tissue (ICT) of the myocardium and human fibroblast culture cells. MCA C5/3 react with the bands of muscle fibers of the myocardium. MCA B6/5 and C5/3 are autoantibodies. It was revealed that these MCA are directed to two streptococcal cross-reacting antigens (CRA). Production of B6/5 and C5/3, apparently, does not depend on the possibility of some streptococcal antigens to bind fibrinogen. Bound immunoglobulins were not revealed in the ICT and in the muscle fibres by the cultivation of the C5/3 monoclone. Firstly it was stated that, MCA B6/5, reacting with fibroblasts and with streptococcal CRA, are capable to fix in the ICT of myocardium, what is typical for the phenomenon described in rheumatic fever.     

The properties of cell wall hydrolysates of Streptococcus group A]

Products obtained from lysis in the cell wall of group A streptococcus have been studied in different growth phases: at the end of the exponential phase and in the stationary one. Endo-beta-N-acetylmuramidase extracted from the culture liquid of Streptomyces levoris 96 has been used for lysis of streptococcus. It is stated that streptococcus cell walls isolated at different growth stages differ in the protein and polysaccharide content. High content of protein in the cell wall of a young culture makes lower the initial rate of the walls' hydrolysis by endo-beta-N-acetylmuramidase. However, with the enzyme penetration into peptidoglycan the rate of hydrolysis of cell walls gets higher and after four-hour incubation the lysis degree of walls of the 16- and 8-hour cultures reaches the equal value (63%). Studies in the protein composition of lysates of the streptococcus cell walls have shown that they contain at least 12 proteins most of which are acid and neutral ones.     

Quantitative determination of the protein and carbohydrate polymers in the cell wall of Streptococcus group A

The content of protein and carbohydrate polymers was estimated in the cell wall of Streptococcus, group A, type 29. A method was developed for analysing peptidoglycane in a polysaccharide-peptidoglycane complex after the prior oxidation by sodium periodate. It was found that the cell wall peptidoglycane bears two carbohydrate and three amino acid residues, i. e. N-acetylglucosamin, muramic acid, glutamic acid, alanine and lysine, in the ratio 1:1:1:4:1, respectively. The data on the cell wall composition prior to and after its oxidation with sodium periodate are given, and the ratio between the main structural components is determined: proteins (60% mol), polysaccharide (23% mol), peptidoglycane (17% mol).     

The formation of delayed hypersensitivity to mycobacterial antigens

In experiments on guinea pigs and BALB/c mice delayed hypersensitivity to mycobacterial antigens was induced by the sensitization of the animals with live BCG or killed Mycobacterium bovis or M. avium in incomplete Freund's adjuvant. In the study of the dynamics of the development of skin reactivity to tuberculin some advantages of the sensitization of guinea pigs with live mycobacteria were revealed, while after the revaccination of the animals no development of secondary cell-mediated immune response was observed. The immunization of guinea pigs with atypical mycobacteria prior to their sensitization with BCG was found to lead to the development of higher skin reactivity to allergen prepared from atypical mycobacteria than skin reactivity to tuberculin.     

The suppression of delayed hypersensitivity to BCG antigens in BALB/c mice during the production of antibodies to the rhamnose determinants of Streptococcus group A polysaccharide]

The data obtained for the first time in our studies indicate that the production of antibodies to group A streptococcal polysaccharide (A-PS), one of the cross-reacting streptococcal antigens, may suppress delayed hypersensitivity (DH) to microbial antigens. The existence of sharply pronounced correlation between the suppression of DH and the presence of antibodies to the rhamnose area of A-PS in the blood of BALB/c mice immunized with the pepsin-treated culture of group A streptococci has been shown. The suppression of DH is absent in the immunized animals of the same group whose blood contains antibodies to the determinant, specific for A-PS. As revealed in this study, the effect of the suppression of antigen-specific cytotoxicity linked with DH to BCG antigens can be reproduced by mixing lymph node cells taken from these two groups of the animals. The data thus obtained are possibly linked with the activation of nonspecific T suppressors in the production of antibodies to the rhamnose determinants of A-PS in the animals immunized with streptococci. The mechanism of the newly discovered phenomenon is discussed.     

Induction of delayed hypersensitivity in guinea pigs by staphylococcal cell wall components

The subcutaneous injection of 100 micrograms of staphylococcal cell-wall peptidoglycan in Freund's incomplete adjuvant leads to the development of sensitization which can be detected on days 7-35 by the splenocyte migration inhibition test. Sensitization can be detected with peptidoglycan, as well as with staphylococcal cell walls. Teichoic acids produce no such effect. The sensitization of guinea pigs with whole staphylococcal cells introduced in three injections also leads to the development of delayed hypersensitivity specific to staphylococcal cell walls, peptidoglycan, but not teichoic acids.     

Immunological study of lysates from the cell wall of group A Streptococcus]

The chemical composition and presence of immunogenic components in the lysates of the cell walls of group A Streptococcus, type M29, were studied. The lysates were prepared with the use of muramidase. Fc-Receptors were detected in the lysates. Within the first 30 minutes of cell wall lysis by muramidase, 4 times higher amounts of the protein reacting with fibrinogen excreted than in the subsequent 4 hours. The lysates contained immunogenic proteins. Fraction III isolated by chromatography of the 30-minute lysate on DEAE-trisacryl formed a single precipitation band with lysate antiserum. The lysate Fraction IV forming three precipitation bands contained a protein not specific of the type. The protein was identical to the protein antigen from Triton X-100 extracts of group A Streptococcus, types M1, M12 and M29. The group-specific polysaccharide was detected in the lysate Fraction I and Fraction II of the 4-hour lysate.     

Biosynthesis of cell wall peptidoglycan and polysaccharide antigens by protoplasts of type III group B Streptococcus.

The formation of a nascent peptidoglycan-group-specific antigen of type III group B Streptococcus at the cell membrane level was demonstrated with an M-1 mutanolysin-prepared protoplast system. Protoplasts of group B streptococci in suitably stabilized medium (20% sucrose) readily incorporated [3H]acetate into cell surface macromolecules. Four major polysaccharides were isolated from the protoplast cultural supernatant fluid: the peptidoglycan group-specific antigen polymer, the group B-specific antigen, and the low-molecular-weight and high-molecular-weight forms of the type III polysaccharide antigen. Biosynthesis of all four polymers was not affected by the action of chloramphenicol, indicating protein synthesis was not required for the production of polysaccharide in this system. However, all but the low-molecular-weight type III antigen were inhibited by the action of bacitracin, suggesting that three of the polymers share a common synthesis-assembly site in the membrane. Attachment of the high-molecular-weight antigen to the nascent peptidoglycan-group B antigen complex did not occur in the protoplast system, suggesting that a more complex cell wall matrix may be necessary before linkage of the high-molecular-weight antigen takes place.     

Heterogeneity of streptococcus group A cell wall protein components

Cell wall surface proteins of group A streptococcus (M 29) were isolated by mild chemical extraction with 1 M hydroxylamine pH 6.0 (37 degrees C). The proteins were purified by ammonium sulfate fractionation, gel filtration on Sephadex G-150 and ion-exchange chromatography on DEAE-Trisacryl M. Using two independent methods (disc electrophoresis in 7.5% PAAG pH 8.9 and high pressure gel filtration), it was shown that after chromatography on Sephadex G-150 the original protein fraction contains up to 8 protein components, while SDS-PAAG electrophoresis performed according to Laemmli revealed up to 25 protein components in the same fraction. During SDS-PAAG electrophoresis six protein fractions performed after ion-exchange chromatography were resolved into 40 protein components whose molecular masses vary from 13 to 80 kDa. Possible reasons for the heterogeneity of surface proteins of group A streptococcus cell wall are discussed.     

Multiple changes in cell wall antigens of isogenic mutants of Streptococcus mutans.

Isogenic mutants of Streptococcus mutans LT11, deficient in the production of the wall-associated protein antigens A and B, were generated by recombinant DNA technology. The hydrophobicity, adherence, and aggregation of the mutants were compared with those of the parent strain. These studies indicated that hydrophobicity, adherence, and saliva- or sucrose-induced aggregation were unaltered in the A- mutant but that hydrophobicity and adherence to saliva-coated hydroxylapatite were greatly reduced in the B- mutant whilst sucrose-dependent adherence and aggregation were increased. To determine whether these changes correlated with changes in the mutated gene product alone, the levels of a number of cell wall antigens were determined in each of the mutants. The loss of antigen A resulted in significantly reduced levels of wall-associated lipoteichoic acid, and loss of antigen B resulted in reductions in both antigen A and lipoteichoic acid. Data presented here thus suggest that changes in the expression of one wall antigen can have a dramatic effect on the levels of others.     

Determination of antibodies against ribosomes and various cell wall components and detection of circulating antigens of group A Streptococcus in patients with erysipelas

The level of antibodies to the ribosomes, polysaccharide A and peptidoglycan of group A streptococcus in the blood of patients with primary, secondary, and often relapsing erysipelas was studied by means of the enzyme immunoassay with the use of the sandwich techniques. For control, the sera of healthy donors were used. In the sera obtained from all groups of erysipelas patients a significant rise in the levels of antibodies to ribosomes and peptidoglycan in comparison with the controls was revealed. An increase in the level of antibodies to polysaccharide A was revealed only in patients with frequently relapsing and secondary erysipelas. Depending on the clinical form and the duration of the disease, polysaccharide A was detected in 32-51.9% of erysipelas patients and protein-ribosomal antigen was detected in 28.6-51.9% of such patients.     

The low-molecular protein of the cell wall in streptococci group A devoid of serological type specificity]

The scheme for the isolation and purification of low-molecular cell-wall protein without type specificity, including the extraction of the cell walls of group A streptococci, type M 29, with 1% solution of Triton X-100, the separation of the extract by ion-exchange chromatography in DEAE-trisacryl M with the subsequent two-stage gel filtration in superfine Sephadex G-50, is described. The isolated protein had a molecular weight of 4,000 daltons and contained no admixtures of group-specific polysaccharide A, phosphorus, nucleic acids and Fc receptors and interacted with antisera to group A streptococcal cells of heterologous type M in the enzyme immunoassay (EIA). Purified protein was characterized by a high content of glycine. The antigenic determinants of immobilized protein, recognized by antibodies in EIA, were sensitive to the action of trypsin and resistant to the action of pepsin, papain, pronase E and sodium periodate.     

Cell wall antigenic determinants in ribosomal preparations of Streptococcus group A

As revealed by double immunodiffusion and the competitive immunoenzyme assay, the immunization of animals with ribosomes isolated from group A streptococci leads to the formation of antibodies to M-protein and does not lead to the formation of antibodies to A-polysaccharide and lipoteichoic acid, which is seemingly caused by the presence of M-protein in ribosomes. Antiribosomal serum has permitted the detection of more antigenic determinants in M-protein than commercial antiserum to homologous M-protein. The immunoenzyme assay for the quantitative determination of ribosomes has been developed.     

Extraction of nontype-specific antigens of group A Streptococcus by potassium thiocyanate

A method for extraction of nontype-specific antigens of the group A streptococcus cellular wall from whole microbial cells is described. Potassium thiocyanate was used as an extracting agent. Nontype-specific antigens of the thiocyanate extract purified by ammonium sulfate precipitation were examined by immunodiffusion in agar gel. The thiocyanate extracts were found to contain several nontype-specific protein antigens part of which were absent from the HCl-extracts. No group A streptococcal polysaccharide was found in the thiocyanate extracts.     

Action of hydrocortisone on the cytotoxic reactions in delayed hypersensitivity to microbial antigens

A study was made of the effect of hydrocortisone (HC) injected to animals with delayed hypersensitivity (DH) to BCG antigens on the cytotoxic activity of lymphocytes and production of lympho- and macrophage toxins. The cytotoxic test with the use of sensitized lymphocytes and preparation of lympho- and macrophage toxins were performed in vitro in the presence of specific microbial antigens. It was shown that HC exerts the most intense inhibitory action on the production of macrophage toxin. High doses of the hormone also inhibited the production of lymphotoxin. At the same time the cytotoxic activity of lymphocytes of the lymph nodes in DH was not inhibited by the employed doses of HC. No reduction was seen either in the sensitivity of autologous adhesive cells (macrophages) used as target cells for studying the cytotoxic activity of lymphocytes.