Isolation of alpha-latrotoxin from karakurt spider venom using monoclonal antibodies

A method of alpha-latrotoxin (LT) isolation from the venom of Latrodectus mactans tredecimguttatus by means of immunoaffinity chromatography on sepharose conjugated with monoclonal antibodies against LT has been developed. This one-step, high-yield, relatively simple and rapid procedure yields active LT for structural and functional studies of its receptor.     

Immunogenic complexes of the soluble surface antigens of Sh. sonnei]

The comparative study of the immunogenic properties of Sh. sonnei (phases I and II) soluble surface antigens obtained by the modified method of aqueous-saline extraction and Sh. sonnei (phase I) antigen obtained by Boivin's method was made with the use of the keratoconjunctival test in guinea pigs. The protective activity of a high molecular fraction obtained by the fractionation of phase I soluble surface antigens in Sepharose 4B was studied. Boivin's antigen, when used for immunization in optimum doses, was found to have pronounced protective properties, whereas phase II soluble surface antigens showed no protective activity. A high molecular fraction obtained from phase I soluble surface antigen was found to be the most immunogenic. Protective activity was largely connected with protein antigen. The question whether protein antigen was an independent protective antigen or whether it constituted a part of a complex which determined the protective activity of a high molecular fraction remained unsolved.     

Mobile gene cassettes and DNA integration elements

Integrons are unique natural systems for capturing and spreading the antibiotic resistance genes among Gram-negative bacteria. Gene transfer into small genomes and into plasmids is via site-specific recombination. Integrons act as receptors of antibiotic resistance cassettes. There are known more than 50 cassettes conferring resistance to beta-lactams, aminoglycosides, trimethoprim, chloramphenicol, streptomycin, and other antibiotics. The structure of integrons and of gene cassettes are described and the mechanisms of capture, mobilization, and expression of cassettes considered.     

Numbers of cells and cell proliferation in intima of different human arteries

Increased cell proliferation in early atherosclerotic lesions is recognized as an essential event of atherogenesis but the levels of cell proliferation in different stages of atherosclerotic plague formation in different types of human large arteries are still insufficiently studied. In the present work, we studied intima thickness and proliferation of newly "infiltrates" hematogenous and resident cells in atherosclerotic lesions of the carotid and coronary arteries and compared these parameters with those in the aorta, reported by us in earlier publication. Analysis of intima thickness and proliferation in grossly unaffected intima and in different types pf atherosclerotic lesions (initial lesions, fatty streaks, lipofibrous, plaques, and fibrous plaque) revealed that although there were similar tendencies in the change of the infiltration levels of hematogenous cells and proliferation in different types of arteries, there were significant quantitative differences between different types of arteries. Hematogenous cells in lipofibrous plaques of the coronary and carotid arteries were found to account for a third and almost for a half of the total cell population, respectively, while atherosclerotic lesions in the aorta, as it has been shown by us earlier, to contain no more than 15% ofhematogenous cells. This suggests that the contribution of hematogenous cells to the development of atherosclerosis in the carotid and the coronary artery appears to be more significant than that in the aorta. Despite the differences in numbers of accumulating hematogenous cells in the intima, a similar "bell-shaped" dependence of cell numbers on the lesion type, involved in the following sequence: unaffected intima-initial lesions-fatty streaks-lipofibrous plaques-fibrous plaques, was detected in the coronary and carotid arteries. The visualization of proliferating cells (PCNA-positive) in atherosclerotic and unaffected zones of the coronary and carotid arteries revealed similar patterns. The maximum numbers of PCNA-positive resident cells were identified in lipofibrous plaques. The changes in the total cell numbers were accompanied by the changes in the numbers of both proliferating resident cells and proliferating hematogenous cells.     

Soluble surface antigens of virulent Sh. sonnei]

The authors conducted an immunochemical analysis of the surface soluble antigen preparations (SSAP) obtained by extraction with physiological saline of the virulent Sh. sonnei microbes killed with acetone. Immunochemical studies by the immunoelectrophoresis and immunodiffusion methods in agar gel, separation on sepharose 4B and in polyacrylamide gel showed the presence of 3 groups of the antigens in the SSAP composition: 1) protein antigens, determining the commonness with the Sonne microbes of the II phase and intergenera associations with typhoid and enteropathogenic E. coli; 2) specific somatic antigen of the Boiven type present in small amounts in the SSAP; 3) specific antigens differing by specificity from the Boiven antigen detected in the microbes of the I phase only and possibly playing a role in the virulent and immunogenic properties of the causative agent.     

Comparative evaluation of the immunological activity of new typhoid vaccines with established prophylactic effectiveness (data from a controlled experiment)]

The authors present the results of studying the immunological efficacy of a dry alcoholic typhoid vaccine enriched with S. typhi Vi-antigen in the assessment of this vaccine in controlled epidemiological trial during the immunization of children aged 7--8 years. O- and Vi-antibodies were tested in the reaction of hemagglutination, H-antibodies--in the agglutination reaction with the microbial diagnostic agent, the properties of antibodies--in a test with cystein, and bactericidal properties of the sera--against the virulent S. typhi strain. Examination of 355 coupled sera obtained before and 3 weeks after the immunization demonstrated a high level of Vi-(1:47) and of the O-(1:580) antibodies and high bactericidal properties of the sera in persons vaccinated with the alcoholic vaccine enriched with the S. typhi Vi-antigen. The results obtained and the data on the formation of prolonged immunity following a simgle immunization suggested that a high protective effect was caused by a combined action of the O- and Vi-antigens contained in the vaccine in optimal doses.