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Biomedical subjects

I M Liampert

Publications and source records attributed to I M Liampert.

At least 37 records · Page 2Linked to original sources
PubMed1986

[Precipitating monoclonal antibodies to 1 of the antigenic determinants of streptococcal group-A polysaccharide].

Monoclonal antibodies (MCA) to streptococcal group A polysaccharide (A-PS) were prepared. Precipitating MCA are directed to the determinant common for A-PS and streptococcal group L polysaccharide (L-PS). The antibodies react in the immunodiffusion test and give identity reaction in A- and L-PS tests. Other MCA are non-precipitating but react with A-PS studied by immunoenzyme method. The reasons for the formation of precipitating and non-precipitating MCA to different antigenic determinants of A-PS are discussed.

Animals↗
PubMed1986

[Monoclonal antibodies to different antigens of skin epithelium obtained by immunizing mice with streptococcus group A antigens].

Monoclonal antibodies (MCA) were obtained by immunization of BALB/c mice with streptococcal group A protein antigens of the cellular wall, or with whole microbial cells. In immunofluorescence test, MCA react with different skin epithelial structures (basal, suprabasal or all the epidermal layers). The majority of MCA belong to autoantibodies. The same MCA revealed no cross-reactions with streptococcal antigens in immunoenzyme and inhibition tests. MCA reacting with epithelial cells are, apparently, obtained as a result of polyclonal activation of the autoreactive clones by streptococcal antigens.

Animals↗
PubMed1986

[Autoantibodies to the thymus and skin epithelium in NZB/N mice and (NZBxNZW)F1 hybrids].

Antibodies reacting with thymus and skin epithelial cells were revealed by indirect immunofluorescence in sera of NZB/N mice and (NZB X NZW)F1 hybrids (B/W) 1-2 and 4-5 months of age. Similar antibodies were not found in sera of BALB/c mice. The inhibition experiments with DNA have shown that antibodies reacting with the thymus and skin epithelium differ from those reacting with the cellular nucleus. Positive reactions with the epithelium were obtained in all thymus and skin tissue samples of humans, guinea-pigs and NZB/N, B/W and BALB/c mice, including autologous tissues of NZB/N and B/W mice. Thus, antibodies reacting with thymus and skin epithelial tissues belong to autoantibodies. These autoantibodies are revealed during the first month of life before the onset of autoimmune processes. The role of these autoantibodies in the damage of thymus epithelium and the development of immunoregulatory disturbances, typical of autoimmune processes, needs further study.

Animals↗
PubMed1985

[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.

Animals↗
PubMed1985

[Determination of antibodies to Streptococcus group A polysaccharide by an immunodiffusion method in human sera in various pathological processes of streptococcal etiology].

A method for the assay of antibodies to the specific antigenic determinant of group A streptococcal polysaccharide (A-polysaccharide) in human sera was developed. The sera were tested in the precipitation test in agar gel with different doses of A-polysaccharide. The presence of a high level of the above-mentioned antibodies is indicative of infection caused by group A streptococcus, but not streptococci of other groups or by the L-forms of streptococci. In 87.5% of patients with primary rheumatism a high level of antibodies to the specific antigenic determinant of A-polysaccharide was detected during the first day of the disease, which confirms most convincingly the etiological role of group A streptococcus in rheumatism. Considerable differences in the level of antibodies to A-polysaccharide in the active and non-active phases of rheumatism have been established, which makes it possible to use the presence of a high level of these antibodies as an indicator of the rheumatic process activity. A considerable percentage of sera with a high level of antibodies to A-polysaccharide was also detected in erysipelas and acute glomerulonephritis patients.

Antibodies, Bacterial↗
PubMed1985

[Determination of antibodies to Streptococcus group A polysaccharide in human sera by an immunoenzyme method].

Use was made of the ELISA to develop a highly sensitive quantitative method for detection of antibodies against Streptococcus group A polysaccharide (polysaccharide A) in human sera. The main advantage is that one can use only one optimal dilution of the sera together with the reference serum. Sera of 53 healthy volunteers and 77 patients with a history of Streptococcus group A infections were screened for the presence of polysaccharide A antibodies. Highly reproducible results were obtained in 97% of cases. The specificity of the method was shown with the polysaccharide A-induced inhibition of the reaction. Positive reactions obtained with the tested sera in gel immunodiffusion correlated with the data derived by the ELISA. Using the latter high level of specific antibodies was found in some of the sera that yielded negative reactions when tested by gel immunodiffusion. This may be associated with the presence of non-precipitating antibodies.

Antibodies, Bacterial↗
PubMed1984

[Cross-reacting antigen of Streptococcus group A and of the stromal fibroblasts of lymphoid organs].

It has been demonstrated by the indirect immunofluorescent method that sera of rabbits immunized with nontype-specific (NTS) proteins of the group A streptococcal cell wall react with cultivated fibroblasts. These fibroblasts were explanted from human and guinea-pig lymphoid organs. The same reactions were observed with F(ab')2 fragments of IgG obtained from antisera to NTS-proteins. Fractions containing NTS-antigens inhibited these reactions. A possible role of the cross-reactive streptococcal antigen in common with the antigen of lymphoid organs during thymic damage and the development of the autoimmune process in rheumatic fever is discussed.

Animals↗
PubMed1982

[Antibodies to fibroblast antigens in the sera of rheumatism patients].

The sera from patients with active rheumatic fever possess unmarked ability to react with antigens of human fibroblasts. More intense reactions were obtained with guinea-pig fibroblasts. In rheumatoid arthritis, positive reactions with human and guinea-pig fibroblasts were disclosed in half of the test sera. No complement-dependent cytotoxic antibodies were found in the patients' sera.

Adult↗
PubMed1981

[Reaction of sera from rabbits immunized with synthetic poly-L-alanine with myocardial interstitial connective tissue cells].

Sera from rabbits immunized with synthetic poly-L-alanine (PL-ala) in complete Freund's adjuvant (CFA) have been examined by the indirect immunofluorescence (IF) technique. Half of the sera reacted with fibroblasts of the interstitial connective tissue of the myocardium. The reactions were obtained with all sections of the myocardium of man and other mammals except rabbits. The sera obtained before or after immunization with synthetic poly-L-lysine fibroblasts were obtained with preparations of IgG or F(ab')2 fragments of IgG isolated from sera of animals immunized synthetic polypeptides can be applied to study by the IF technique of the antigenic structure of tissues including lymphoid and tumor tissues.

Animals↗
PubMed1980

[Cross reactions between polysaccharides of group A, L, and A-variant streptococci].

In group A and A-variant streptococcal antisera the presence of antibodies reacting with group L streptococcal polysaccharide (L polysaccharide) was revealed. Group A and A-variant streptococcal polysccharides (A and V polysaccharides) were shown to be partially identical to L polysccharide by means of the precipitation test in agar gel. Experiments in inhibiting the reactions of the above mentioned antisera with A, V and L polysaccharide preparations suggest the presence of a determinant common to all these polysccharides and differing from the "ramnose" determinant of the polysaccharides and from the determinant characteristic of A polysaccharide. In the identification of group A streptococci by the immunological methods, as well as in the study of cross reactions with the tissues of mammals, the possible presence of antibodies against various antigenic determinants of A polysaccharide, one of which is also common to L polysaccharide, should be taken into consideration.

Animals↗
PubMed1980

[Antibodies to non-type-specific group A streptococcal cell wall antigens in human sera].

The use of gel immunodiffusion for the determination of antibodies to nontype-specific cell-wall protein antigens of group A streptococcus allowed to eliminate reactions caused by antibodies to type-specific antigens, group polysaccharide and teichoic acid. Antibodies to nontype-specific antigens, and particularly to two such antigens, occurred more frequently in the blood sera of patients with rheumatism in the active phase than in patients with rheumatism in the inactive phase, erysipelas and with non-rheumatic cardiac diseases, and in donors. Antibodies to nontype-specific antigens occurred in the blood sera of patients with rheumatism in the inactive phase and with non-rheumatic cardiac diseases as frequently as in donors. The occurrence of these antibodies in the blood sera of erysipelas patients was significantly more frequent than in donors; but antibodies to two nontype-specific antigens occurred in erysipelas patients, in contrast to patients with rheumatism in the active phase, not more frequently than in donors. Patients with rheumatism and erysipelas seem to differ in their immune response to certain nontype-specific streptococcal antigens.

Antibodies, Bacterial↗
PubMed1980

[Isolation of high affinity antibodies to streptococcal group A polysaccharide reacting with thymus and cutaneous epithelial cells].

Anti-streptococcal A polysaccharide (anti-A polysaccharide) antibodies were isolated from sera of rabbits immunized with group A streptococci by means of immunosorbents. The antibodies were studied by indirect immunofluorescence method on sections of skin and thymus tissues. Most preparations of high affinity antibodies reacting with A polysaccharide in the immunodiffusion test also react with skin and thymus epithelial cells. No preparations of low affinity anti-A polysaccharide antibodies reacted with thymus or skin epithelium. It was found that the reaction of antibodies to A-polysaccharide with epithelial cells does not depend on the availability of antibodies cross reacting with group L streptococcal polysaccharide. The reaction with thymus and skin epithelial cells is likely to be bound with high affinity antibodies to the specific determinant of A-polysaccharide.

Animals↗
PubMed1980

[Study of cross reactions between group A streptococcal antigens and cardiac interstitial connective tissue fibroblasts of different species of mammals].

It has been revealed by indirect immunofluorescence that sera of rabbits immunized with group A streptococcal non-type-specific antigens and F (ab')2 fragments of IgG obtained from these sera intensively react with fibroblasts of interstitial connective tissue (ICT) of the myocardium of humans and different mammalian species with the exception of rabbits. Negative or weak reactions with the same sera and F (ab')2 fragments were observed with fibroblasts of ICT of nonimmunized rabbits. Myocardial ICT of immunized animals showed bound immunoglobulins. This model can be used for making clear the reason for presence in sera of rheumatic patients circulating antibodies only to heterologous but not to homologous ICT of the myocardium regardless of the revealing bound immunoglobulins in the ICT of these patients.

Animals↗