Relaxation channels of multi-photon excited xenon clusters.

The relaxation processes of the xenon clusters subjected to multi-photon excitation by laser radiation with quantum energies significantly lower than the thresholds of excitation of atoms and ionization of clusters were studied. Results obtained by means of the photoelectron spectroscopy method showed that desorption processes of excited atoms play a significant role in the decay of two-photon excited xenon clusters. A number of excited states of xenon atoms formed during this process were discovered and identified.

[The use of streptococcal immunoglobulin Fc receptors in the technology of producing a pseudotuberculosis diagnostic test system]. / Ispol'zovanie streptokokkovykh immunoglobulinovykh Fc-retseptorov v tekhnologii polucheniia diagnosticheskoi psevdotuberkuleznoi test-sistemy.

The conditions of obtaining the IgM from hyperimmune sera to Yersinia pseudotuberculosis have been established. The process includes the adsorption of these sera by streptococci belonging to serological groups G and A and having receptors which bind the Fc-fragment of IgG and IgA molecules. The data confirming the fact that specific antibodies to Y. pseudotuberculosis belong to IgM have been obtained. The use of isolated IgM fractions for the preparation of a pseudotuberculosis diagnostic assay system has made it possible to establish that the new method of obtaining sensitin is economical and ensures a 3.5-fold greater yield of the conjugate and simplifies the technological cycle of its preparation.

Role of streptococcal IgG Fc receptor in tissue deposition of IgG in rabbits immunized with Streptococcus pyogenes.

Induction of anti-IgG during hyperimmunization of rabbit with Streptococcus pyogenes (group A streptococci; GAS) was previously shown to require the presence of IgG Fc receptors (FcR) in the vaccine strain. In the present work, we examined whether streptococcal FcR activity might also be of importance for heart and kidney deposition of IgG, known to occur in poststreptococcal sequelae as well as during experimental immunization of animals. Each of three IgG-binding (GAS types M1, M12 and M22) and two non-binding (GAS type T27 and S. agalactiae (GBS) type Ia) streptococcal strains were used for intravenous immunization of rabbits during two periods of eight and six weeks, respectively, separated by an interval of one month. Before use, vaccine strains were treated with KSCN and carefully washed in order to remove any surface-bound immunoglobulins. No deaths occurred among injected rabbits. No tissue deposition was elicited by the GAS type T27 or the GBS strain. In contrast, the strains of types M1, M12 and M22 all induced deposits of IgG in kidney and heart tissue, beginning during the first immunization period. In two tested animals, receiving GAS of types M1 or M22, circulating immune complexes containing anti-IgG antibodies were also detected. Finally, serum autoantibodies reacting with preparations of heart and kidney, but not lung or liver, were demonstrated in each of six animals receiving M1 or M22, reaching maximum levels during reimmunization; such antibodies were not evoked by the two strains not binding IgG. Our results suggest that, in GAS with capacity for non-immune binding of IgG, triggering of anti-IgG acted to enhance tissue deposition of IgG or immune complexes in immunized rabbits. Furthermore tissue-specific antibodies were elicited only by the IgG-binding strains and occurred comparatively late during immunization, suggesting that those antibodies might have been triggered due to the exposition of hidden kidney and heart determinants.

[Use of group A-specific polysaccharide antigen conjugated with protein carrier for detection of specific anti-polysaccharide antibodies]. / Ispo'lzovanie gruppospetsificheskogo A-polisakharidnogo antigena, ko''niugirovannogo s belkovym nositelem, dlia vyiavleniia spetsificheskikh antipolisakharidnykh antitel.

Group-A specific polysaccharide antigen has been obtained by extraction of streptococcal suspension using 4N NaNO2 and glacial acetic acid, conjugated with bovine serum albumin using CNBr. Testing of the preparation with a set of rabbit anti-sera by enzyme immunoassay (EIA) and passive hemagglutination reaction (PHR) revealed its antigenic specificity both in direct experiments and in N-acetyl-D-glucosamine absorption. Forty-seven sera of EIA-studied individuals and 35 sera of PHR-studied ones, all with group-specific polysaccharide antigen, were examined. Immune reactions showed the broad spectrum of antibody titres in the studied sera. Complete correlation of anti-polysaccharide antibodies detected by the two techniques was observed in the sera with high specific antibody titres. A possibility to use the obtained group-A specific polysaccharide antigen to detect anti-polysaccharide antibodies in the sera of streptococcal infection patients is discussed.