Immune response to Encephalitozoon cuniculi infection in laboratory mice.

The study was performed to determine the immune response to Encephalitozoon cuniculi infection in immunocompetent mice during 120 days of experiment. Mice infected with E. cuniculi had an increased number of CD4+ T cells up to Day 20 post infection (p.i.), but counts of CD8+ T lymphocytes were significantly lower up to Day 90 p.i. in peripheral blood. Blood monocytes were significantly increased on the Day 60 and Day 120 of infection. A lack of significant decrease of CD4+ T cells may be considered as an important event in the immune response to E. cuniculi infection in immunocompetent mice.     

The immune response in a dog to Encephalitozoon cuniculi infection

The immune response to Encephalitozoon cuniculi infection in a dog was investigated by means of the indirect fluorescent antibody test, the leucocyte migration inhibition test and the radial immunodiffusion test for serum IgG and IgM levels. Specific antibodies were detected within 7 days of infection and they persisted for 370 days. A cell-mediated immune response was detected from Day 13 following infection until Day 97. Histopathological examination showed plasma cell infiltration of the kidneys, meninges, lung, bladder, smooth muscle and spleen.     

Application of chemi- and bioluminescence in studies of immunological reactions against protozoa

The opsonization and lysis of different protozoa by antibodies and/or complement was followed using luminol-dependent chemiluminescence and bioluminescence. The addition of immune serum to variable antigen type populations of Trypanosoma evansi led to the specific opsonization of trypanosomes resulting in an intense metabolic activation and chemiluminescence response of phagocytic cells. In comparison to those of uninfected control mice, the phagocytosis of coccidia merozoites by spleen cells from mice infected with Eimeria falciformis was enhanced during the acute stage of a primary infection. Opsonizing activity was demonstrated in phosphate-buffered saline extracts of gut contents of mice infected for 10 days. The incubation of E. falciformis merozoites together with guinea-pig complement resulted in slow lysis of the cells. The addition of mouse serum collected greater than 6 days after an infection led to an accelerated lysis of the merozoites, indicating the appearance of complement-fixing antibodies in the serum. Heat-inactivated immune serum alone had no lysing activity on merozoites. In the presence of complement, bovine lymphoblastoid cells infected with Theileria annulata were lysed by anti-lymphoblastoid cell serum raised in mice but not by serum from cattle which had developed immunity to Theileria annulata.     

Regulation of murine macrophage phagocytosis of sheep erythrocytes by T-2 toxin

The effect of a single oral dose of 4 mg of T-2 toxin/kg of body weight on in vivo phagocytosis of sheep RBC by peritoneal macrophages was evaluated in nonsensitized mice and in mice sensitized with sheep RBC. T-2 toxin treatment had no effect on the viability or phagocytic activity of resident peritoneal macrophages in nonsensitized mice. However, a significant (P less than 0.005) increase in phagocytic activity occurred in cells from mice treated with toxin and subsequently sensitized with sheep RBC. In contrast, phagocytosis of sheep RBC was significantly (P less than 0.05) suppressed in cells from mice treated with toxin after sensitization. Toxin treatment induced necrosis of lymphocytes and significant decreases in thymus and spleen weights. Seemingly, T-2 toxin, administered at a dose that caused marked lymphoid depletion, suppressed or enhanced in vivo macrophage phagocytic activity in antigenically sensitized mice, and enhancement or suppression of phagocytosis was a function of the time of toxin treatment in relation to antigenic stimulation.     

绢蒿水煎剂对小鼠免疫功能的影响

为了探讨新疆石河子南山地区牧草绢蒿对正常小鼠和环磷酰胺所致免疫低下小鼠的免疫调节作用,采用脾脏系数测定法、脾脏淋巴细胞ANAE染色法、姬姆萨-瑞特氏染色法、MTT法、抗支原体抗体ELISA法及大肠杆菌攻毒试验分别对小鼠脾脏指数、T淋巴细胞数量、巨噬细胞吞噬活性、脾脏淋巴细胞增殖、抗体分泌功能及抗致病性大肠杆菌感染能力等指标进行研究。结果表明,高、低浓度的绢蒿水煎剂均能不同程度提高免疫低下小鼠和正常小鼠的T淋巴细胞数量及腹腔巨噬细胞吞噬功能;高、低浓度的绢蒿水煎剂均能不同程度提高正常小鼠的脾脏淋巴细胞增殖能力;低浓度的绢蒿水煎剂能提高正常小鼠对大肠杆菌的抗感染能力;高浓度的绢蒿水煎剂能下调免疫低下小鼠和正常小鼠的脾脏指数,下调正常小鼠的血清抗体效价。提示,绢蒿水煎剂对免疫低下小鼠有一定的增强免疫作用,对正常小鼠具有双向免疫调节作用。本研究结果为进一步开发绢蒿免疫调节剂提供了依据。     

Diagnosis and manifestation of encephalitozoonosis in mice after experimental infection with different species and application of dexamethasone

Twenty-eight BALB/c mice were infected with different strains of Encephalitozoon species (Encephalitozoon cuniculi II - mouse type, E. cuniculi III - dog type, Encephalitozoon hellem, Encephalitozoon intestinalis). Five of them were infected with E. cuniculi II (mouse type) and simultaneously immunosuppressed with dexamethasone. Clinical signs of encephalitozoonosis were not remarkable. Ascites was found in two mice of dexamethasone-treated group 14 days post-infection (p.i.). The histopathological changes were found mainly in spleen and liver in the form of lymphoepithelioid granuloma. Spores were found in faeces since day 14 p.i. and visualized by Calcoflour White M2R. After cultivation on cellular cultures (VERO E6 - monkey kidney cells, RK-13 - rabbit kidney fibroblasts), the species differentiation was performed by PCR using panmicrosporidial primers (PMP1, PMP2) and specific primers (ECUN-F, ECUN-R, V1, SI-500). The differences were recorded in the immune response of immunocompetent and immunosuppressed mice. At day 60 p.i., the titres of specific antibodies measured by indirect immunofluorescence antibody test were lower (1:4096) in dexamethasone-treated mice when compared with non-immunosuppressed animals (1:8196). The significant increases of antibody titres were recorded in particular infected groups within the experiment (P < 0.01 between day 14 p.i. and day 30 p.i., P < 0.001 between day 14 p.i. and day 60 p.i.). Experimental encephalitozoonosis in non-immunosuppressed and immunosuppressed mice provides a useful model for the study of immune response and lesions associated with these protozoans.     

Immunological and gene expression responses to a Salmonella infection in the chicken intestine

Besides infection in humans, Salmonella enteritidis can also cause serious illness in young chickens. However, the genetic and immunological parameters important for the disease in chickens are not well characterized. In this study, processes in the chicken intestine in response to a Salmonella infection were investigated in two different chicken lines. One-day-old chickens were orally infected with Salmonella. T-cell subpopulations, phagocytic properties of intestinal mononuclear cells and RNA expression levels of the jejunum were investigated. The two chicken lines differed in the amount of cfu in the liver and growth retardation after the infection. Differences in phagocytic activity of intestinal mononuclear cells were found between control and Salmonella infected chickens. The number of CD4+ T-cells of the intestine decreased after the Salmonella infection in one chicken line, while the number of CD8+ T-cells increased in both chicken lines, but the time post infection of this increase differed between the lines. In one chicken line the expression levels of the genes carboxypeptidase M and similar to ORF2 decreased after the Salmonella infection, which might be related to a decrease in the amount of macrophages. With the microarray, ten genes were found that were regulated in only one of the chicken lines, while we found six genes regulated in response to the infection in both chicken lines. So differences in genetic background of the chickens influence the intestinal host response of the Salmonella infection as observed by phagocytic activity, gene expression and changes in the number of T-cell subpopulations and macrophages.     

绢蒿水煎剂对小鼠免疫功能的影响

目的：研究新疆石河子南山地区牧草绢蒿对正常小鼠和环磷酰胺所致免疫低下小鼠的免疫调节作用。方法：采用脾脏系数测定法、脾脏淋巴细胞ANAE染色法、姬姆萨-瑞特氏染色法、抗支原体抗体ELISA法及大肠杆菌攻毒试验,分别对小鼠脾脏指数、T淋巴细胞数量、巨噬细胞吞噬活性、抗体分泌功能及抗致病性大肠杆菌感染能力等指标进行研究。结果：高、低浓度的绢蒿水煎剂均能不同程度地提高免疫低下小鼠和正常小鼠的T淋巴细胞数量及腹腔巨噬细胞吞噬功能;低浓度的绢蒿水煎剂能提高正常小鼠对大肠杆菌的抗感染能力;高浓度的绢蒿水煎剂能下调正常小鼠血清抗体效价和脾脏指数。结论：绢蒿水煎剂对免疫低下小鼠有一定的免疫增强作用;对正常小鼠具有双向免疫调节作用。研究结果为进一步开发绢蒿免疫调节剂提供了依据。     

Experimental Burkholderia pseudomallei infection of pigs

Experimental infection with Burkholderia pseudomallei was successfully produced after a single intravenous challenge of 2-month-old pigs with a dose of 5.0 x 10(9) bacterial cells. Clinical, paraclinical and morphological findings of the infectious process and post-infectious immunity were examined up to day 30 post infection (p.i.). A transient and short hyperthermia accompanied by enhanced and longer demonstrated pulse frequency. An increased erythrocyte sedimentation rate and tachypnea were observed too after clinical examination. The infection starts with significant leucopenia, and a reduced number of alveolar and peritoneal macrophages which have been overcome in the latest intervals of infection. In contrast, the phagocytic activity of leucocytes was statistically increased during the course of infection and up to day 15 p.i. in the case of alveolar macrophages. Burkholderia pseudomallei was able to colonize the lungs during the whole experiment and was only present 3 days in the spleen and mesenterial lymph nodes (MLN). Significant antibody response was developed as early as day 7 p.i. Hyperaemia, haemorrhages and necrotic foci were found in the brain, liver spleen and MLN. Lung tissue was also hyperaemic, with formation of small abscesses and signs of catarrhal pneumonia. Data obtained in this study revealed that B. pseudomallei causes a chronic generalized infection in pigs, even after intravenous challenge.     

In vitro antibody response to the tetrapeptide repeats of Plasmodium falciparum circumsporozoite protein by splenocytes from mice infected with P. yoelii yoelii

The antibody response to the recombinant protein, R32tet32, which contained the repetitive sequence (NANP)n of Plasmodium falciparum CSP was determined in C57BL/6 mice during the course of nonlethal infection with Plasmodium yoelii 17X. Marked suppression of the IgG antibody response to R32tet32 occurred when mice were immunized at peak parasitemia (on day 16). In vitro antibody responses of spleen cells from acutely infected mice to R32tet32 were similarly suppressed. Stimulation of normal spleen cells cultured for 5 days with 100 ng/ml of R32tet32 gave an optimal IgG antibody response, but spleen cells from infected mice obtained at peak parasitemia failed to respond to a broad range of antigen concentrations. Cocultivation studies employing enriched lymphocyte populations from infected and uninfected C57BL/6 mice indicated that both T and B cells from infected mice were defective in their response to R32tet32. The response to the repetitive region was restored by the addition of recombinant mouse interleukin-2 (IL-2) at a dose of 50 U/ml to cultures of spleen cells from infected mice.     

The role of phagocytic cells in enhanced susceptibility of broilers to colibacillosis after Infectious Bronchitis Virus infection

Colibacillosis results from infection with avian pathogenic Escherichia coli bacteria. Healthy broilers are resistant to inhaled E. coli, but previous infection with vaccine or virulent strains of Infectious Bronchitis Virus (IBV) predisposes birds for severe colibacillosis. We investigated whether IBV affects recruitment and function of phagocytic cells and examined NO production, phagocytic and bactericidal activity, and kinetics of peripheral blood mononuclear cells (PBMC) and splenocytes. Moreover, we measured cytokine mRNA expression in lung and spleen samples. Broilers were inoculated with IBV H120 vaccine or virulent M41 and challenged 5 days later with E. coli 506. A PBS control and E. coli group without previous virus inoculation were also included. Birds were sacrificed at various time points after inoculation (h/dpi). Inoculation with IBV induced extended and more severe colibacillosis than with E. coli alone. At 4dpi, the number of KUL-01(+) PBMC in all E. coli-inoculated groups was significantly higher than in PBS-inoculated birds, which correlated with lesion scores. From 1 to 4dpi, NO production by PBMC from all E. coli-inoculated animals was elevated compared to PBS birds. Bactericidal activity of PBMC in IBV-inoculated animals at 7dpi was lower than in PBS- and E. coli-inoculated birds, but phagocytic capacity and recruitment were not severely impaired. In spleen samples of IBV-infected animals reduced expression of IL-1beta, IL-6, IL-8, IL-10, IL-18 and IFN-gamma mRNA was found 1dpi. Our results suggest that enhanced colibacillosis after IBV infection or vaccination is caused at least by altered innate immunity and less by impairment of phagocytic cell function.     

Differences in the immune response against ruminant chlamydial strains in a murine model.

CBA/J mice were used in the present study to establish differences between the immune response to three chlamydial strains: AB7 (Chlamydia psittaci wild-type strain), 1B (C. psittaci vaccinal strain) and iB1 (C. pecorum). The evolution of chlamydial infection was evaluated in each strain by studying the clinical signs, the number of bacteria isolated from the spleen and the pathology of the liver. Three aspects of the immune response were then studied: the characterization of the infiltrate of leukocytes in the liver, the percentages of T- and B-cells, macrophages and neutrophils in the spleen, and the presence of cytokines in the serum. Infection followed a different course in the C. psittaci-infected mice; 1B-infected mice showed milder levels in all the parameters analysed than their AB7-infected counterparts. The resolution of infection was earlier in 1B-infected mice and, although the immune response to both strains was Th1-like, a more intense CD8+ T-cell response and an earlier presence of TNF-alpha in serum were observed in this group. C. pecorum infection was controlled mainly by a non-specific immune response, since these mice showed no signs of a systemic specific immune response. Neutrophil depletion experiments showed that these cells play a very limited role in the non-specific response against C. pecorum.     

Establishment of inflammatory model induced by Pseudorabies virus infection in mice

BackgroundPseudorabies virus (PRV) infection leads to high mortality in swine. Despite extensive efforts, effective treatments against PRV infection are limited. Furthermore, the inflammatory response induced by PRV strain GXLB-2013 is unclear.ObjectivesOur study aimed to investigate the inflammatory response induced by PRV strain GXLB-2013, establish an inflammation model to elucidate the pathogenesis of PRV infection further, and develop effective drugs against PRV infection.MethodsKunming mice were infected intramuscularly with medium, LPS, and different doses of PRV-GXLB-2013. Viral spread and histopathological damage to brain, spleen, and lung were determined at 7 days post-infection (dpi). Immune organ indices, levels of reactive oxygen species (ROS), nitric oxide (NO), and inflammatory cytokines, as well as levels of activity of COX-2 and iNOS were determined at 4, 7, and 14 dpi.ResultsAt 10⁵–10⁶ TCID₅₀ PRV produced obviously neurological symptoms and 100% mortality in mice. Viral antigens were detectable in kidney, heart, lung, liver, spleen, and brain. In addition, inflammatory injuries were apparent in brain, spleen, and lung of PRV-infected mice. Moreover, PRV induced increases in immune organ indices, ROS and NO levels, activity of COX-2 and iNOS, and the content of key pro-inflammatory cytokines, including interleukin (IL)-1β, IL-6, tumor necrosis factor-α, interferon-γ and MCP-1. Among the tested doses, 10² TCID₅₀ of PRV produced a significant inflammatory mediator increase.ConclusionsAn inflammatory model induced by PRV infection was established in mice, and 10² TCID₅₀ PRV was considered as the best concentration for the establishment of the model.     

Hepatic lesions in rabbits infected with Encephalitozoon cuniculi administered per rectum.

Microsporidia have been recognized recently as opportunistic pathogens in acquired immunodeficiency syndrome patients. In an attempt to develop an animal model of enteric microsporidiosis, adult (5 to 6 months old) male Flemish Giant rabbits from a closed New York colony were administered 5 x 10(3), 5 x 10(5), and 5 x 10(7) Encephalitozoon cuniculi per rectum. Rabbits given 5 x 10(5) and 5 x 10(7) E. cuniculi had moderate granulomatous periportal infiltrates, characterized by the presence of numerous macrophages, epithelioid cells and a few multinucleated giant cells, lymphocytes, and plasma cells. Inflammatory cells also were seen infiltrating the tunica adventitia and tunica media of hepatic portal veins and branches of the hepatic artery. This study demonstrates that administration of E. cuniculi per rectum to rabbits results in infection that is characterized by high frequency and severity of hepatic lesions.     

Characterization of the innate and adaptive immunity to Salmonella enteritidis PT1 infection in four broiler lines

Four broiler lines were inoculated orally with Salmonella enteritidis phage type 1 at the age of 7 days (experiment A: lines 1 and 2) and at the age of 1 day (experiment B: lines 3 and 4). At various days post-infection chickens were sacrificed and the number of Salmonella in the caeca, liver, and spleen were determined. Furthermore, phagocytic activity, cellular immune responses, and humoral responses were determined using, respectively, single-cell suspensions of spleen or intestine and serum. In both experiments, similar trends were seen. Increased numbers of S. enteritidis were found in the caeca of lines 1 and 3, whereas at the same time a decreased colonization was found in the spleen and in the liver, as compared to lines 2 and 4. In the latter two lines, the phagocytic activity of the phagocytes was higher and the humoral responses were lower. Observations from this study suggest that lower activity of phagocytes and higher humoral activity prevent systemic S. enteritidis infection.     

Immunomodulatory effects of betulinic acid from the bark of white birch on mice

The objective of this study was to explore the immunomodulatory effects of betulinic acid (BA) extracted from the bark of white birch on mice. Female mice were orally administered BA for 14 days in doses of 0, 0.25, 0.5, and 1 mg/kg body weight. We found that BA significantly enhanced the thymus and spleen indices, and stimulated lymphocyte proliferation induced by Concanavalin A and lipopolysaccharide as shown by MTT assay. Flow cytometry revealed that BA increased the percentage of CD4⁺ cells in thymus as well as the percentage of CD19⁺ and the ratios of CD4⁺/CD8⁺ in spleen. BA increased the number of plaque-forming cell and macrophage phagocytic activity as indicated by a neutral red dye uptake assay, and the peritoneal macrophages levels of TNF-α were also increased. In contrast, serum levels of IgG and IgM and serum concentrations of IL-2 and IL-6 were significantly decreased in BA-treated mice compared to the control as assayed by haemagglutination tests and ELISA, respectively. Taken together, these results suggest that BA enhances mouse cellular immunity, humoral immunity, and activity of macrophages. Thus, BA is a potential immune stimulator and may strengthen the immune response of its host.     

Experimental encephalitozoonosis in neonatal dogs

The in vivo infection of neonatal dogs by the microsporidian protozoan parasite, Encephalitozoon cuniculi, was studied. Microscopic examination of tissues from infected animals showed granulomatous nephritis, meningoencephalitis, hepatitis, and pneumonitis. A large component of the inflammatory infiltrate consisted of plasma cells and lymphocytes. In addition, hyperplasia of B-lymphocyte-dependent regions of lymph nodes and erythrophagocytosis were consistently seen in infected dogs. Infected dogs developed lymphocytosis, hypergammaglobulinemia, anti-encephalitozoon antibodies, and an antigen-specific blastogenic response to E. cuniculi spores. Lymphocyte blastogenic responses to the lectin phytohemagglutinin A (PHA) were depressed compared to controls. Dogs dying during the 2-month experimental trial were bacteremic. The findings of these experiments suggest that postnatal infection results in a demonstrable although seemingly ineffective immune and inflammatory response without detectable clinical disease.     

Effect of an immunopotentiator on Aeromonas salmonicida infection in rainbow trout (Salmo gairdneri)

The immunoactive peptide FK-565 (heptanoyl-y-D-glutamyl-(L)-mesodiaminopimelyl-(D)-alanine) was found to induce protection against intraperitoneal Aeromonas salmonicida infection in rainbow trout (Salmo gairdneri Richardson). The survival rate was as high as 60% when FK-565 was given intraperitoneally as a single dose (1mg/kg) one day before bacterial challenge. A non-specific stimulation of phagocytic cells by FK-565 at an early stage of the bacterial infection may contribute to the resistance observed. The phagocytic activity of peritoneal phagocytic cells as well as phagocytic cells of the pronephros were stimulated by FK-565 in vivo and in vitro, respectively, as compared to untreated control fish. Furthermore, decreased activity of phagocytic cells previously immunosuppressed with cyclophosphamide was rapidly restored by application of FK-565.     

黑木耳多糖对小鼠免疫功能的影响

从黑木耳中提取多糖,研究其对小鼠免疫功能的影响。通过灌胃的方法检测不同剂量黑木耳多糖对小鼠免疫器官发育、溶血素生成和巨噬细胞吞噬功能的影响。结果显示,黑木耳多糖可明显提高小鼠脾脏和胸腺指数,促进脾脏及胸腺的发育,促进巨噬细胞的吞噬活性,明显增强小鼠的体液免疫功能。研究表明黑木耳多糖具有明显的增强小鼠免疫功能的作用。     

芝芪菌质多糖的制备及其增强免疫活性的初步研究

为研究芝芪菌质多糖体外免疫活性增强作用,本研究采用水提、醇沉、离子交换层析等方法纯化芝芪菌质多糖,并对各多糖组分(GAP-1、GAP-2、GAP-3、GAP-3)进行小鼠脾细胞增殖、NK细胞活性以及小鼠腹腔巨噬细胞吞噬鸡红细胞活性的测定。结果表明:纯化的4种芝芪菌质多糖在10-3mg/mL～10-1mg/mL浓度范围内均能够显著增强ConA诱导的小鼠脾淋巴细胞增殖反应;在25mg/kg～100mg/kg剂量范围内均能够显著增强小鼠腹腔巨噬细胞吞噬鸡红细胞活性,而且呈剂量依赖性,其中以GAP-3效果最为明显;对NK细胞活性也有不同程度的增强作用,其中,GAP-3在浓度为100μg/mL时,NK细胞的杀伤率为27%,与IL-2阳性对照组比较,有显著增强作用(p0.05)。本研究证明,纯化的芝芪菌质多糖具有较好的体外增强免疫活性,为芝芪菌质作为增强机体免疫力的饲料添加剂提供了理论依据。