Field trials with an oral cell-free vaccine made from Shigella flexneri

The data on the study of the reactogenicity, safety and prophylactic potency of a new acellular vaccine prepared from S. flexneri 2a antigenic complexes are presented. According to the results of two epidemic experiments, the vaccine, introduced by oral administration, showed low reactogenicity, safety and sufficient prophylactic potency. The vaccine decreased morbidity rate in dysentery caused by S. flexneri 2a and ensured the protection of 74% (72-80%) of the vaccinees. The complete course of immunization consisting of three administrations followed by the booster administration induces the formation of specific immunity whose duration is sufficient for ensuring the protection of immunized persons during the epidemiologically unfavorable period (for at least 3 months).     

Action of Na-RNA on infection in mice infected with Shigella flexneri]

Experiments were conducted on albino mice. Experimentally induced dysentery infection proved to become aggravated under the effect of yeast Na-RNA expressed in the increase of the number of animals which fell ill and perished. This phenomenon proved to be based on the acceleration of reproduction of the causative agent, with a simultaneous selection of its virulent clones seen both in vitro and in vivo.     

Histopathological study of rabbit intestinal mucosa infected with a hybrid strain of Shigella dysenteriae 1 carrying LPS biosynthesis genes of Salmonella enterica serovar typhimurium

The rfb gene cluster and the rfc gene of Salmonella enterica were introduced earlier into an invasive Shigella dysenteriae 1 strain by triparental cross. Antiserum was raised in rabbit against lipopolysaccharide isolated from the hybrid strain. Both the hybrid and the invasive S. dysenteriae 1 strain were found to have a titer of 1:2560 while for S. enterica, it was 1:640. Ligated ileal loops were prepared in rabbit, which were inoculated with 10(8) CFU ml(-1) each of the hybrid strain, and invasive S. dysenteriae 1 strain used as positive control. Escherichia coli K12 was also used as a negative control. After 18 h, the fluid accumulation ratios were 0.2 and 1.6 for hybrid and invasive strains of S. dysenteriae 1, respectively. Rabbit intestinal mucosa infected with hybrid S. dysenteriae 1 strain showed the presence of intact villus tips and unruptured intestinal mucosa whereas total necrosis of intestinal mucosa and villi was observed in the S. dysenteriae 1-infected region.     

Intrarectal immunization with rotavirus 2/6 virus-like particles induces an antirotavirus immune response localized in the intestinal mucosa and protects against rotavirus infection in mice

Rotavirus (RV) is the main etiological agent of severe gastroenteritis in infants, and vaccination seems the most effective way to control the disease. Recombinant rotavirus-like particles composed of the viral protein 6 (VP6) and VP2 (2/6-VLPs) have been reported to induce protective immunity in mice when administered by the intranasal (i.n.) route. In this study, we show that administration of 2/6-VLPs by the intrarectal (i.r.) route together with either cholera toxin (CT) or a CpG-containing oligodeoxynucleotide as the adjuvant protects adult mice against RV infection. Moreover, when CT is used, RV shedding in animals immunized by the i.r. route is even reduced in comparison with that in animals immunized by the i.n. route. Humoral and cellular immune responses induced by these immunization protocols were analyzed. We found that although i.r. immunization with 2/6-VLPs induces lower RV-specific immunoglobulin G (IgG) and IgA levels in serum, intestinal anti-RV IgA production is higher in mice immunized by the i.r. route. Cellular immune response has been evaluated by measuring cytokine production by spleen and Peyer's patch cells (PPs) after ex vivo restimulation with RV. Mice immunized by the i.n. and i.r. routes display higher gamma interferon production in spleen and PPs, respectively. In conclusion, we demonstrate that i.r. immunization with 2/6-VLPs protects against RV infection in mice and is more efficient than i.n. immunization in inducing an anti-RV immune response in intestinal mucosa.     

黄连素对肠道黏膜免疫功能的调节作用

黄连素(berberine)是在中国传统医药中广泛应用的广谱抗菌药物,临床上主要用于治疗肠道细菌感染性疾病。肠道黏膜免疫是机体防止感染的第一道防线,并在宿主与外环境间黏膜稳态的建立和维持上发挥着重要作用。近年来,中医药对肠道黏膜免疫的研究已成为国内外学者的研究热点,现就黄连素在肠道黏膜免疫中的调控作用作一综述。     

Anti-bacterial and anti-endotoxic immunity, induced by the administration of an enterobacterial vaccine

The work demonstrates that the sera of animals immunized with enterobacterial vaccine, when adsorbed on sheep red blood cells sensitized with glycolipid Re, lose their capacity of decreasing the lethal effect of Shigella sonnei endotoxin, which is indicative of the antiendotoxic action of antibodies. At the same time, immune sera obtained after immunization with enterobacterial vaccine contain antibodies having also other specificity and thus ensuring antibacterial immunity.     

Alterations of the intestinal innervation in mice infected with Schistosoma mansoni.

Schistosomiasis mansoni is a parasitic disease in which granulomas form around schistosome eggs in the liver and intestines. The purpose of this study was to determine the alterations in the intrinsic innervation of the distal ileum and proximal colon resulting from schistosomiasis. Using murine schistosomiasis mansoni, we examined light microscopic preparations stained with osmium-zinc iodide or the dihydronicotinamide adenine dinucleotide: nitro BT oxidoreductase (NADH) method. We also examined specific populations of peptidergic nerves (vasoactive intestinal polypeptide and substance P) using an avidin-biotin complex (ABC) immunohistochemical technique. We found that granulomas focally destroyed the enteric nerves. Occasionally nerves were found within granulomas, particularly at the periphery of the lesions. Nerve cell bodies close to granulomas had altered staining, which included increased staining for vasoactive intestinal polypeptide. The distribution of nerve injury varied between the 2 enteric segments studied. In the distal ileum, the principal injury was to the myenteric plexus; whereas, the submucous and mucosal plexuses were predominantly damaged in the proximal colon. The physiologic significance of this injury to the enteric nerves requires elucidation.     

Cells containing IgE in the intestinal mucosa of mice infected with the nematode parasite Trichinella spiralis are predominantly of a mast cell lineage

To determine whether IgE+ cells in the intestinal mucosa of nematode-infected mice were of a mast cell or a lymphocyte lineage, the intestinal mucosae of mast cell-deficient w/wv mice were examined for IgE+ cells after inoculation with Trichinella spiralis muscle-stage larvae. Immunofluorescence staining techniques were used to detect IgE associated with cells in the intestinal mucosa. Comparisons were made among four strains of mice, w/wv (mast cell-deficient), +/+ (normal congenic littermates of w/wv), BALB/c, and SJL, that were either uninfected controls or inoculated with T. spiralis. Tissue sections from the small intestine of T. spiralis-infected BALB/c, SJL, and +/+ mice were fixed in ethanol and were stained with an affinity-purified F(ab')2 rabbit anti-mouse IgE followed by FITC goat anti-rabbit IgG. Large numbers of cells in the intestinal mucosa exhibited bright fluorescence. When other sections of intestines from these mice were processed in Carnoy's fixative and were stained with alcian blue at low pH (a metachromatic stain for mast cells) or alcian blue followed by immunofluorescence staining for IgE, large numbers of mast cells were observed in the intestinal mucosa, and 70 to 90% stained positively for IgE. There was a considerable number of cells in the intestinal mucosa which were IgE+ but which did not stain with alcian blue. Few alcian blue-positive cells and no IgE+ staining cells were present in the intestinal mucosa of control, uninfected +/+, BALB/c, and SJL mice. To determine whether these IgE+ alcian blue-negative cells were of a lymphocyte or a mast cell lineage, the mast cell-deficient w/wv mouse strain was examined after infection with T. spiralis. In contrast to BALB/c, SJL, or +/+ mice, few cells in the intestinal mucosa of T. spiralis-infected w/wv mice stained with alcian blue or were positive for IgE. However, when the IgE response in the MLN of the w/wv mice was compared to the IgE response of BALB/c, SJL, and +/+ mice, numerous IgE+ cells, but no alcian blue-positive cells, were observed in the parenchyma of the MLN from all four strains of T. spiralis-infected mice. In addition, flow microfluorometric analysis of MLN cells stained for surface IgE in suspension showed a comparable proportion of IgE-bearing cells, which were mostly B lymphocytes, among all four strains of T. spiralis-infected mice.(ABSTRACT TRUNCATED AT 400 WORDS)     

Immune complex formation during the passive immunization of mice infected with the tick-borne encephalitis virus

The results of investigations, indicating that the development of the infectious process in experimental encephalitis is accompanied by the formation of immune complexes circulating in the blood and localized in the brain tissue, are presented. The intravenous injections of a homologous serum preparation into intact animals induces the appearance of a rather low level of circulating immune complexes, which precedes the elimination of antibodies. The intravenous injection of a specific serum preparation two days after the infection of the animals with tick-borne encephalitis virus is accompanied by the formation of immune complexes; the course of infection is not aggravated.     

Resolution of multiclonal infections of Trypanosoma cruzi from naturally infected triatomine bugs and from experimentally infected mice by direct plating on a sensitive solid medium

The isolation of biological clones of Trypanosoma cruzi by microscopically dispensing individual organisms or by serial dilution is laborious and time consuming. The inability to resolve mixed T. cruzi infections, from vectors and hosts, and to isolate clones of slow growing genotypes by efficient plating on solid media, has hindered characterisation studies and downstream applications. We have devised and validated a sensitive, solid medium plating technique for rapid in vitro isolation of clones representative of all the recognised T. cruzi lineages (TCI, TCIIa-e), including the slow growing strain CANIII (TC IIa) and Trypanosoma rangeli, with high plating efficiencies. Furthermore, the method is effective for the isolation of clones directly from silvatic triatomine bugs and from experimentally infected mice harbouring mixed infections, allowing resolution of multiclonal infections from varied sources.     

Effect of antibiotic and vaccine therapies on the succinate dehydrogenase and phosphatase activity of liver cells of mice infected with Staphylococcus

Changes in the activity of succinate dehydrogenase (SDH), total and acid phosphatase (TP and AP) were studied in treatment of laboratory animals with rifampicin, lincomycin and with inactivated staphylococcal vaccine used alone or in combinations. It was shown that immunization of the animals with inactivated staphylococcal vaccine under conditions of experimental staphylococcal infection promoted stimulation of the enzyme activity. Rifampicin and lincomycin used for the treatment of such animals lowered the activity of the enzymes. The suppressing effect of the antibiotics increased with an increase in the period of their use. It should be noted that the inhibitory effect of rifampicin on the activity of SDH, TP and AP was less pronounced than that of lincomycin. The combined use of the vaccine and antibiotics for the treatment of the animals promoted an increase in the enzyme activity as compared to the use of the antibiotics alone. Sometimes the activity of SDH, TP and AP reached the control levels in such animals or the levels observed in the animals treated with the vaccine alone. Stimulation of the enzyme activity was more pronounced when the vaccine was used in combination with rifampicin.     

Cellular immune responses in mice infected with the intestinal nematode Trichuris muris.

CBA and B10.BR mice show variation in immune response to the intestinal nematode Trichuris muris. CBA mice develop strong resistance, eliminating worms from the intestine; B10BR mice are permissive and develop chronic infections. It is already known that resistance and permissiveness reflect differential T helper responses. The data reported here show that resistant CBA mice express good antigen-specific lymphocyte proliferative responses to infection, whereas cells from B10.BR mice are relatively anergic, although still responsive to Concanavalin A (ConA). The possibility that the altered proliferative responsiveness seen in infected B10.BR mice reflected quantitative or qualitative changes in T helper cells was examined by comparing cytokine production and expression of cell surface markers (CD4, CD8, and CD28) in mesenteric lymph node cells and spleen cells from both strains and comparing these with the characteristics of cells from resistant CBA mice and from CBA mice that had been rendered permissive to infection by a combination of irradiation and corticosteroid treatment. As expected, cells from B10.BR mice produced high levels of interferon-gamma (IFN-gamma), whereas those from CBA mice released high levels of IL-5, whether stimulated with adult worm somatic antigens, excretory/secretory antigens, or ConA. Immunosuppressed CBA mice produced high levels of both IFN-gamma and IL-5 throughout the experiment. FACS analysis revealed a decrease of CD4+ and an initial increase in CD8+ cells in all infected mice. No major changes occurred in the relative proportion of CD28(+) cells. Further evaluation of the CD28 costimulatory molecule, measured as mean fluorescence intensity, displayed down-regulation in permissive and immunosuppressed mice. The data obtained suggest that lymphocyte unresponsiveness and permissiveness to T. muris infection may be associated with a down-regulation or an initially reduced expression of costimulatory CD28 molecules.     

不同液体复苏对失血性休克大鼠肠粘膜的影响

目的：观察不同液体复苏对失血性休克大鼠肠粘膜的影响以及肠粘膜的变化。方法：利用大鼠失血性休克模型以及不同的补液方式,在复苏后120分钟时处死大鼠,取回肠4cm,做病理切片并根据Chiu等方法评估回肠黏膜上皮损伤指数。结果：液体复苏组的肠粘膜损伤程度小于休克不补液组（p〈0.05）,而限制型液体复苏组的肠粘膜损伤程度小于充分液体复苏组（p〈0.05）。结论：通过本实验对肠粘膜的观察可以得出,对于失血性休克,液体复苏时有效的抗休克方式,而对于复苏的方式来说,从肠黏膜的保护方面来说,限制型液体复苏是优于传统的充分液体复苏的。