[IMMUNOLOGIC MONITORING OF HELICOBACTER PYLORI PERSISTENCE IN THE ORGANISM].

Generalized results of 15-year prospective studies of frequency of occurrence and dynamics of circulation of pathogenetically significant LPS/O-antigens, high molecular weight proteins, including CagA, and VacA of Helicobacter pylori in biological media of organism in patients with gastrointestinal diseases and asymptomatic volunteers due to effects of external and internal factors are presented. Features of antigen circulation and reciprocal immune reaction of the organism are established, that reflect their interaction in the parasite-host tandem, risk and prognosis of possible complications in the process of long-term persistence of Helicobacter pylori in the organism.

Diagnostic significance of the coagglutination reaction in patients with the diarrhoea syndrome.

Specific soluble Shigella, Salmonella and Yersinia enterocolitica antigens were determined in biological fluids (saliva, urine, coprofiltrate) from 268 patients with the diarrhoea syndrome using the coagglutination reaction. The findings suggest that the coagglutination reaction (COA) is a simple and efficient method suitable for the fast diagnosing of acute intestinal infection (AII) in the early days from the onset of the disease. COA enables the identification of specific antigens associated with the causative agents of intestinal infections in 79-54% of patients with shigellosis and salmonellosis. COA was shown to possess a high diagnostic potential in AII of unknown etiology. Shigella, Salmonella and Yersinia antigens were determined in 47.7, 23.4 and 10.8% of cases respectively where no bacterial excretion could be confirmed. Two and less frequently three antigens being identified simultaneously in 10.8% cases. The identification of opportunistic microorganisms in AII using the COA does not appear to be sufficient to confirm their etiological significance as Shigella and Salmonella antigens were simultaneously determined in most patients.

[Interrelation of virulent and avirulent (vaccinal) strains of Shigella flexneri 2A in long-term bacterial carriage in gnotobiotic rats]. / Vzaimootnosheniia virulentnogo i avirulentnogo (vaktsinnogo) shtammov Shigella flexneri 2A pri dlitel'nom bakterionositel'stve u krys-gnotobiontov.

The ability of S. flexneri 2a virulent and avirulent (vaccine) strains No. 516 and No. 516 m to displace one another during long-term carrier state in germ-free rats has been studied. The long-term persistence of the vaccine strain in the intestine of the rats has been shown to produce colonization resistance to subsequent infection with the virulent culture of these bacteria. During carrier state in rats progressive S--R dissociation of the bacteria occurs, type II antigen is lost with simultaneous retention of group 3, 4 antigens and the resulting transformation of S. flexneri, serotype 2a, into variant y; the virulence of Shigella S-forms is also lost.

[Increased sensitivity of immune macrophages to the cytotoxic action of virulent shigellae]. / Povyshenie chuvstvitel'nosti immunnykh makrofagov k tsitotoksicheskomu deistviiu virulentnykh shigell.

The in vitro interaction of live bacteria belonging to virulent and avirulent Shigella and Salmonella strains with peritoneal macrophages obtained from mice immunized by the intragastric administration of these bacteria has been studied. In contrast to Salmonella-activated macrophages capable of resisting the intracellular proliferation and the cytopathic action of homologous bacteria, Shigella-activated macrophages become more sensitive to the cytopathic action of virulent shigellae. The ability of shigellae to render an aggravating cytopathic effect on the activated macrophages correlates with the virulence of dysentery bacilli and is practically absent in avirulent strains, including S. flexneri 2a No. 516 M vaccine strain.