F4 receptor-independent priming of the systemic immune system of pigs by low oral doses of F4 fimbriae

Oral administration of F4 fimbriae of Escherichia coli induces intestinal mucosal immune responses in F4 receptor-positive (F4R(+)) pigs, but not in F4R(-) pigs. We examined whether F4 fimbriae in F4R(-) animals behave like a food antigen and can induce oral tolerance. Therefore, F4R(+) and F4R(-) pigs were fed 2mg of F4 and challenged i.m. to evaluate the effect of oral F4 on the systemic immune system. As control antigen, two different oral doses (2 and 600 mg) of OVA were used. Thirty days after the i.m. OVA challenge, the OVA-specific serum IgG titre in 600 mg-fed pigs was lower than that in non-fed animals, indicating that tolerance was induced. Conversely, in the 2mg-fed pigs a rapid increase of OVA-specific IgG with higher titres than those in non-fed pigs was seen following challenge, indicating a priming of the systemic immune system. A similar priming was seen in both F4-fed F4R(-) and F4R(+) pigs. Upon challenge, non-fed pigs displayed a primary immune response with a slow increase of F4-specific serum IgG, whereas F4-fed F4R(-) and F4R(+) pigs showed secondary responses with a rapid increase of serum IgG. This was expected in F4R(+) pigs, as in these animals oral F4 induces F4-specific antibody-secreting cells in the spleen, suggesting a priming of the systemic immune system. However, also the F4-fed F4R(-) pigs displayed a secondary response, despite the failure to detect a response upon oral F4 administration. These findings suggest that the F4 antigen, at a dose of 2 mg, behaves like a common food antigen in F4R(-) pigs, namely it induces a systemic priming.     

Effect of tannic acid on the immune response of growing chickens

Effects of tannic acid (TA) on the immune response of growing chickens were studied in two experiments. In the first experiment, 25 or 30 g TA/kg diet was added to a control diet; added TA reduced (P less than .05) weight gain, protein efficiency rate and weight of bursa of Fabricius, thymus and spleen. Total IgM and IgG immunoglobulin levels (primary and secondary immune responses) against killed Brucella abortus were reduced in TA-fed chickens. Numbers of total white blood cells and absolute lymphocytes also were reduced. Tannic acid feeding also resulted in the involution of bursal follicles. In second experiment, TA-treated birds were challenged with a live culture of Brucella abortus. The total IgM and IgG levels again were depressed along with lymphoid organ weights of treated birds. Persistence of B. abortus in spleens of TA-treated birds was higher. These data suggest that the administration of tannic acid impairs the immune function of growing chickens in a dose-dependent manner.     

Comparison of adjuvants with respect to serum IgG antibody response in orally immunized chickens

We have previously shown that oral immunization with non-replicating antigens hardly induced serum IgG antibody response in chickens and addition of sodium fluoride (NaF) to the immunogen markedly improved their immunological states. In the present study, taurine, lithium and Quillaja saponin (Q-SAP) were compared with NaF with respect to their enhancement of serum IgG antibody response in chickens after oral immunization. The antibody titer of chickens which received Q-SAP as the mucosal adjuvant tended to be higher than that of chickens which received antigen plus NaF. Simultaneous administration of antigen with lithium or taurine elicited a higher antibody titer in chickens compared to those of chickens orally immunized with antigen alone, but the effect of these two adjuvants was less efficient compared with that of NaF. These results suggested that Q-SAP as well as NaF is useful as an oral adjuvant for chickens.     

Maternal immunity enhances systemic recall immune responses upon oral immunization of piglets with F4 fimbriae

F4 enterotoxigenic Escherichia coli (ETEC) cause diarrhoea and mortality in piglets leading to severe economic losses. Oral immunization of piglets with F4 fimbriae induces a protective intestinal immune response evidenced by an F4-specific serum and intestinal IgA response. However, successful oral immunization of pigs with F4 fimbriae in the presence of maternal immunity has not been demonstrated yet. In the present study we aimed to evaluate the effect of maternal immunity on the induction of a systemic immune response upon oral immunization of piglets. Whereas F4-specific IgG and IgA could be induced by oral immunization of pigs without maternal antibodies and by intramuscular immunization of pigs with maternal antibodies, no such response was seen in the orally immunized animals with maternal antibodies. Since maternal antibodies can mask an antibody response, we also looked by ELIspot assays for circulating F4-specific antibody secreting cells (ASCs). Enumerating the F4-specific ASCs within the circulating peripheral blood mononuclear cells, and the number of F4-specific IgA ASCs within the circulating IgA⁺ B-cells revealed an F4-specific immune response in the orally immunized animals with maternal antibodies. Interestingly, results suggest a more robust IgA booster response by oral immunization of pigs with than without maternal antibodies. These results demonstrate that oral immunization of piglets with F4-specific maternal antibodies is feasible and that these maternal antibodies seem to enhance the secondary systemic immune response. Furthermore, our ELIspot assay on enriched IgA⁺ B-cells could be used as a screening procedure to optimize mucosal immunization protocols in pigs with maternal immunity.     

Efficacy of different adjuvants to potentiate the immune response to Mycoplasma strain F-38

Summary A study was carried out to determine the efficacy of different adjuvants in enhancing antibody response to sonicated F-38 antigens. Goats were immunised against CCPP using antigens incorporated in Freund's incomplete adjuvant (IFA), saponin, aluminium hydroxide gel and buffered saline (PBS) respectively. Antibody responses were determined. The goats were challenged four months after immunisation to assess their immune status. Two of eight goats given antigen in PBS, six of 10 goats given antigen in aluminium hydroxide, seven of eight goats given antigen in IFA and all 10 goats given antigen in saponin withstood the challenge. Saponin and IFA were similar in their immune potentiation ability and were superior to aluminium hydroxide. As IFA has been considered unsuitable for use in food animals saponin may prove valuable in vaccination of goats against CCPP caused by mycoplasma strain F-38.

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Eficacia De Diferentes Adjuvantes Para Potenciar La Respuesta Inmune A La Cepa De Micoplasma F-38

Resumen Se llevó a cabo un estudio para determinar la eficacia de diferentes adjuvantes, para mejorar la respuesta inmume de antígenos F-38 sonicados. Un grupo de cabras fue inmunizado contra pleuroneumonía contagiosa caprina usando antígenos incorporados en adjuvante incompleto de Freund, soponia, hidróxido de aluminio y solución salina tampón respectivamente. Se determinaron las respuestas inmunes. Las cabras fueron descargadas con cepas virulentas, cuatro meses después de la inmunización. Dos de ocho cabras a las cuales se les inoculó el antígeno en solución salina tampón, seis de 10 las cuales recibieron el antígeno en hidróxido de aluminio, siete de ocho que recibieron el antígeno en adjuvante de Freund y todas las 10 que recibieron el antígeno en soponina, resistieron la descarga. La soponina y el adjuvante de Freund, fueron similares en cuanto a la habilidad potenciador, siendo superiores al hidróxido de aluminio. Debido a que el adjuvante de Freund no se considera apropiado para usarlo en animales dedicados al consumo, la soponina podría ser valiosa en la vacunación de cabras contra la pleuroneumonía contagiosa caprina producida por la cepa F-38.

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Efficacite De Differents Adjuvants Pour Potentialiser La Reponse Immune Au Mycolplasme Souche F-38

Résumé On a entrepris une étude pour déterminer l'efficacitè de différents adjuvants augmentant la réponse en anticorps aux antigènes F-38 ultrasonnés. Les chèvres ont été immunisées contre la PPCC avec des antigènes respectivement incorporés dans un adjuvant de Freund incomplet (AF1), de la saponine, du gel d'alumine et un tampon PBS. Les réponses sérologiques ont été suivies. Les chèvres ont été éprouvées 4 mois après l'immunisation pour déterminer leur immunité. Deux chèvres ont résisté: deux chèvres sur huit ayant reçu l'antigène dans le PBS, six sur dix ayant reçu celui avec hydroxyde d'alumine, sept sur huit ayant reçu celui avec AF1 et toutes celles ayant reçu l'antigène avec la saponine. La saponine et l'AF1 sont identiques quant à leur capacité immuno-potentiatrice et sont supérieurs à l'hydroxyde d'alumine. Etant donné que l'AF1 est considéré comme inutilisable chez les animaux destinés à la consommation, la saponine peut se révéler utile pour les vaccinations des chèvres contre la PPCC causée par le mycoplasme souche F-38.

     

Cell-mediated and humoral immune response of chickens to Mycoplasma synoviae.

The leukocyte migration-inhibition test was employed to demonstrate the presence of cell-mediated immunity and to ascertain its relation to immunoglobulin production in Mycoplasma synoviae infection in chickens. With peripheral leukocytes and a preparation of M. synoviae used as antigen, good discrimination was obtained between naturally or experimentally infected birds and uninfected control birds. Only the infected groups showed significant inhibition. Positive migration inhibition values developed in the second week of infection, often before the appearance of hemagglutination-inhibition titers, and continued to accompany the production of immunoglobulins with some degree of correlation for at least 6 or 12 months.     

Both flagella and F4 fimbriae from F4ac+ enterotoxigenic Escherichia coli contribute to attachment to IPEC-J2 cells in vitro

The role of flagella in the pathogenesis of F4ac⁺ Enterotoxigenic Escherichia coli (ETEC) mediated neonatal and post-weaning diarrhea (PWD) is not currently understood. We targeted the reference {"type":"entrez-nucleotide","attrs":{"text":"C83902","term_id":"2706834","term_text":"C83902"}}C83902 ETEC strain (O8:H19:F4ac⁺ LT⁺ STa⁺ STb⁺), to construct isogenic mutants in the fliC (encoding the major flagellin protein), motA (encoding the flagella motor), and faeG (encoding the major subunit of F4 fimbriae) genes. Both the ΔfliC and ΔfaeG mutants had a reduced ability to adhere to porcine intestinal epithelial IPEC-J2 cells. F4 fimbriae expression was significantly down-regulated after deleting fliC, which revealed that co-regulation exists between flagella and F4 fimbriae. However, there was no difference in adhesion between the ΔmotA mutant and its parent strain. These data demonstrate that both flagella and F4 fimbriae are required for efficient F4ac⁺ ETEC adhesion in vitro.     

肠毒素性大肠杆菌菌毛对产蛋鸡免疫性的研究

采用热抽提法提取4种肠毒素性大肠杆菌菌毛蛋白。K88、K99、F41和987p菌毛蛋白分别制成弗氏佐剂苗;K88还制成白油佐剂苗,氢氧化铝胶苗和蜂胶佐剂苗;另将4种菌毛等比例混合制成弗氏佐剂苗。分别对产蛋鸡进行免疫,用微量凝集反应和血凝抑制试验检测卵黄抗体效价。结果表明,K88菌毛较其他3种菌毛免疫性好,诱导抗体效价最高而且能长时间维持;987p菌毛能快速诱导抗体的产生,但整体效价低。K88不同佐剂苗中,铝胶佐剂能较快地诱导抗体的产生,蜂胶佐剂苗抗体持续时间短,弗氏佐剂能诱导高效价的抗体产生而且能长时间持续。     

The effect of dietary lysine deficiency on the immune response to Newcastle disease vaccination in chickens

The effect of lysine deficiency on chicken immune function was evaluated using broiler chickens fed a diet with lysine at 67% of the control diet (1.24% lysine). The evaluation of humoral immune function was conducted by measuring the antibody production to a live Newcastle disease virus (NDV) vaccination using the hemagglutination inhibition (HI) test and enzyme-linked immunosorbent assay (ELISA). The cellular immune function was evaluated through the use of cutaneous basophil hypersensitivity test. The antibody response to NDV vaccination was reduced in broiler chickens fed a lysine-deficient diet when measured by ELISA but not when measured by HI. The cell-mediated immune response was also reduced by lysine deficiency.     

康泰宁对雏鸡免疫性能及抗氧化能力的影响

为了研究中药康泰宁制剂对雏鸡免疫功能及抗氧化能力的影响,试验将120羽京白雏鸡随机分为4组,分别为康泰宁高(1.2%)、中(0.8%)、低(0.4%)中药剂量组和对照组。在28,49日龄时,每组随机抽取6羽雏鸡剖杀,摘取胸腺、法氏囊和脾脏称重计算免疫器官指数,测定血清中新城疫(ND)抗体效价,并对血清中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性和丙二醛(MDA)含量进行测定。结果表明:康泰宁能显著提高雏鸡免疫器官指数。其中、高剂量组雏鸡新城疫抗体效价显著高于对照组;高剂量组SOD和CAT活性显著高于对照组,MDA含量显著降低。说明中药康泰宁可增强雏鸡免疫功能,并有效提高雏鸡抗氧化能力。     

Modification of humoral immune response in chickens following treatment with carrageenan

Carrageenan treatment of chickens resulted in splenomegaly and enlargement of bursa but had no effect on the thymus. The dose and route of administration had a profound effect on humoral immune response to Brucella abortus and sheep red blood cells. Antibody response to B. abortus was either unaffected or significantly enhanced, whereas response to red blood cells was severely suppressed. Furthermore, delineation of the class of antibody response affected by the treatment, using 2-mercaptoethanol, suggested that there was a selective inhibition of IgG response to the T dependent antigen.     

Crossbreeding parameters of general immune response traits in White Leghorn chickens

Crossbreeding parameters of immune response traits were estimated from a set of well characterized crossbred populations derived from three chicken lines selected over 12 generations for three different general immune response traits and their F1, F2 and backcrosses. The three traits investigated were the selection criteria from each of the lines, i.e. antibody response to the Newcastle disease virus vaccine 3 weeks after vaccination (ND3), cell-mediated immune response (response to phytohemagglutinin, PHA) and phagocytic activity measured as carbon clearance (CC). Crossbreeding parameters included direct and maternal additive line effects, direct and maternal heterosis as well as direct epistatic recombination loss. They were estimated as linear combinations of genetic group effects estimated using animal model methodology. Significant line differences were obtained for ND3 and, to a lesser extent, CC. They were mainly due to direct effects, maternal effects being significant for none of the 3 traits. Significantly negative direct heterosis effects were also observed for ND3 and CC, but not for PHA. Maternal heterosis effects were not estimated for CC. They were non significant for PHA, and negative and significant (− 0.78 ± 0.24) for ND3. The significant favourable recombination gain estimated for ND3 (3.21 ± 0.88) indicates that epistatic interactions could be important for this trait.The present work shows that it was worthwhile to complete second generation crosses to be able to assess to what extent immunity gained by selection is maintained in advanced crossbred generations, and to compare the transmission of immune traits implicated in different aspects of immunity.     

Sex-related differences in immune response and survival rate of broiler chickens

In a comparison between male and female broiler chicks, the mortality rate of males was found to be significantly higher than that of females, starting from the second week of age until marketing at 7 or 8 weeks of age. The main causes of death during this period were various infectious diseases. This observation was explained by differences in the activity of humoral and cell-mediated immune responses between the sexes. In tests of antibody responses of young chicks to a variety of antigens (bacterial-E. coli, viral-Newcastle disease virus, and protein antigen-bovine serum albumin), females responded 24-72 h earlier than males and with higher peak antibody titers. In-vitro proliferation of T-lymphocytes to purified protein derivative and E. coli showed an earlier and greater response in females. The correlation between immune responsiveness and survival, as tested by challenging vaccinated chicks with pathogenic E. coli, showed a significantly higher mortality rate in vaccinated males, that was correlated with their lower antibody titer. We concluded, therefore, that sex-related differences in mortality rates of broiler chicks may result from a less efficient immune response in males.     

灵芝多糖对雏鸡免疫功能的影响

灵芝为多孔菌科赤芝的子实体，味淡，性温，无毒。祖国传统医学认为，灵芝可“滋阴补肾、扶正固本”。现代药物化学研究表明，其主要有效成分为灵芝多糖，是调节机体免疫功能的主要物质，可提高小鼠腹腔巨噬细胞吞噬鸡红细胞的能力，激活巨噬细胞，主要表现在促进白介素-2生成和增强T细胞亚类功能，促进免疫细胞的增殖，激活杀伤细胞活性，并可拮抗某些免疫抑制。     

Effect of reticuloendotheliosis virus on the response of chickens to Salmonella typhimurium infection

Groups of 25 chickens free of maternal antibody to reticuloendotheliosis virus (REV) were inoculated with either third or seventh passage REV at either one or seven days of age. Some of the birds inoculated at day 1 with REV were inoculated with Salmonella typhimurium either concurrently or six or 13 days later while some of those inoculated with REV at day 7 were inoculated concurrently with S typhimurium. At day old, infection with S typhimurium alone caused the death of 12 of 25 chicks whereas in the dual infection, using the third passage REV, 18 of 25 birds died. Similarly no seven or 14 day old chickens died when challenged with S typhimurium alone, but previous day-old infection with REV caused a respective mortality of eight of 25 and five of 25 birds. With the seventh passage REV a similar pattern was seen. At day old S typhimurium infection alone killed seven of 25 birds whereas combined with virus the mortality was 14 of 25 and while S typhimurium alone killed none of 25 chicks infected at seven days old, the mortality in birds also infected with REV was 14 of 25. Combined virus and bacterial infections did not increase the proportion of feathering defects in birds surviving S typhimurium infections. There was a significantly higher proportion of feathering defects in birds infected with third passage virus compared with seventh passage virus. Although a higher proportion of birds had antibody responses to REV in the seventh than in the third passage group, there was no discernible difference in the effect the different viruses had on chickens' susceptibility to S typhimurium.     

Cell mediated and humoral immune response of chickens to inactivated oil-emulsion infectious bronchitis vaccine

A lymphocyte transformation microassay was used to study cell mediated immunity (CMI) in chickens following primary and secondary vaccination with inactivated oil emulsion infectious bronchitis (IB) vaccine and subsequent challenge with Massachusetts-41 (M-41). Humoral immunity was monitored for comparison, using the haemagglutination inhibition (HI) microassay. Positive stimulation indices (2 to 2.7 after primary and 2 to 4.8 after secondary vaccination) were lower and HI titres were higher than those previously reported following primary and secondary vaccination with live IB vaccines. The highest HI titres appeared in birds which had received the inactivated vaccine as a secondary vaccination. Challenge of vaccinated and revaccinated birds resulted in strong HI and weak CMI secondary responses. There was no correlation between CMI and HI antibody production. Monitoring egg production and clinical signs showed that a high level of protection against challenge resulted from revaccination with an inactivated oil adjuvant vaccine.     

Effect of exposure to a short-duration sound on the stress response of chickens

Chickens were subjected to the sound produced by banging on a metal pail (104 decibels) for 30 seconds. Heterophil/lymphocyte (H/L) ratios began to rise 18 hours later, reaching their maximum value (0.62) in 20 hours and returning to pre-stress values after 30 hours. Neither resistance to Escherichia coli challenge infection nor antibody response were altered.