Intradermal testing of swine to monitor changes in delayed hypersensitivity response

Pigs were tested (intradermal injection) on the abdomen with either phytohemagglutinin (PHA) or PHA and tuberculin. The response to PHA was consistent; double-skin thickness averaged 247% of the preinjection thickness during daily testing. Pigs that were primed with Freund's complete adjuvant had a mean double-skin thickness of 208% for tuberculin and 236% for PHA, indicating that the mitogen induced an antigen-like response. Unexpectedly, injections of dexamethasone (0.1 mg/kg of body weight on 2 days) increased the reactivity to both tuberculin and PHA, indicating that the lymphocyte and macrophage response to dexamethasone in swine may be slightly different than the response reported in other species.     

Delayed-type skin hypersensitivity and in vitro lymphocyte immunostimulation responses of swine following inoculation with Mycobacterium avium cell walls and a mycobacterial immunopotentiating glycolipid

Miniature swine (n = 5 per group) were inoculated intradermally with mineral oil-in-water emulsions containing either 150 μg of mycobacterial immunopotentiating glyco-lipid P3 (EP3), 150 μg of lyophilized Mycobacterium avium (serotype 8) cell walls (E-MaCW), or 150 μg P3 and 150 μg M. avium cell walls (EP3-MaCW). Swine vaccinated with E-MaCW and EP3-MaCW developed antigen-sensitive lymphocytes detectable with delayed-type hypersensitivity (DTH) skin tests and lymphocyte transformation assay. Swine injected with EP3 were not sensitized. In general EP3-MaCW evoked a more pronounced in vivo DTH tuberculin skin test and in vitro lymphocyte transformation responses than E-MaCW. Time-course studies indicated a more persistent response in swine injected with EP3-MaCW than in those given E-MaCW. Commercial type Yorkshire swine (n = 5) inoculated intradermally with EP3-MaCW developed cell-mediated immune (CMI) responses to avian tuberculin detectable in vivo with delayed-type skin hypersensitivity and in vitro with lymphocyte immunostimulation responses.     

Effects of cyclophosphamide on the lymphoid tissues and humoral and cellular immune responsiveness of young calves.

Cyclophosphamide (CY) was given IV to 5-month-old calves (ten doses; each dose of 5.0 mg/kg, 2-day intervals between doses). The effects of CY on circulating leukocytes, lymphoid tissues, and the humoral and cellular immune responses were assessed. The numbers of total leukocytes, lymphocytes, and neutrophils and platelets decreased significantly. The lymphocyte population was depleted in the cortex of the thymus and B-dependent areas of the spleen and lymph nodes. Significant decreases occurred in the frequency of the peripheral blood lymphocytes-bearing surface immunoglobulin (Ig) and in serum IgM and IgG concentrations. Primary serum antibody responses to avian erythrocytes and Brucella abortus strain 19 antigens were diminished or delayed. The blastogenic responses of peripheral blood lymphocytes to phytohemagglutinin P, concanavalin A, pokeweed mitogen, and to purified protein derivative and B abortus antigens were enhanced as was the delayed hypersensitivity reaction to the tuberculin skin test. While a diminished humoral immune response was associated with CY treatment, the cell-mediated response was potentiated. The effect of CY was transitory with most variables returning to near base line within 24 days after CY was ceased.     

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.     

Lack of immunostimulatory effect of N-acetyl muramyl-l-alanyl-d-isoglutamine on selected chicken immune functions

Synthetic N-acetyl muramyl-l-alanyl-d-isoglutamine, syn. muramyl-dipeptide (MDP) was found to be immunostimulatory in several experimental animal species. In order to determine the influence of MDP on the chicken immune response, different doses (0.05–0.2 mg) of this compound were administered to 6-week old chickens, and cellular as well as humoral immune functions were tested. Neither the immune response against sheep red blood cells or Newcastle disease virus (strain Hitchner B 1), nor the ability to reject skin grafts, or to react in the delayed hypersensitivity (tuberculin) test, were affected significantly under the experimental conditions employed. This study reveals little evidence for parallels between the ability of the chicken immune system and the immune system of other animal species examined so far, to develop enhanced immune reactions under the influence of MDP.     

Interdigital skin test for evaluation of delayed hypersensitivity and cutaneous basophil hypersensitivity in young chickens

A skin test to assess T-cell mediated delayed hypersensitivity (DH) and cutaneous basophil hypersensitivity (CBH) was evaluated in the interdigital skin of young chickens. Three-day-old chickens were sensitized with Mycobacterium tuberculosis, and the DH reaction was elicited in the interdigital skin in 10-, 17-, 24-, and 31-day-old chickens by intradermal injection of tuberculin. Cutaneous basophil hypersensitivity was elicited in the interdigital skin of 10- and 14-day-old chickens by a single intradermal injection of phytohemagglutinin-P (200 micrograms). The effect of immunosuppression on the results of interdigital skin test for DH and for CBH was evaluated in chickens that were treated with dexamethasone daily for 4 days before testing. The DH reaction, as indicated by a significant (P less than 0.01) increase in the mean interdigital skin thickness, was detectable in 10-day-old chickens and was consistently evident in 17-, 24-, and 31-day-old chickens. The DH response in the interdigital skin of 24-day-old chickens was comparable with that elicited in the standard wattle test. The CBH reaction, as indicted by a significant increase (P less than 0.005) in skin thickness, was evident in the interdigital skin of 10- and 14-day-old chickens. Treatment with dexamethasone significantly decreased (P less than 0.01) the DH and CBH reactions. Results of the study indicated that the interdigital skin test may be used to evaluate normal and suppressed cell-mediated DH and CBH reactions in chickens as young as 10 and 14 days old.     

Dietary lutein stimulates immune response in the canine

The possible immuno-modulatory action of dietary lutein in dogs is not known. Female Beagle dogs (17-18-month old; 11.4+/-0.4kg body weight) were supplemented daily with 0, 5, 10 or 20mg lutein for 12 weeks. Delayed-type hypersensitivity (DTH) response to saline, phytohemagglutinin (PHA) and a polyvalent vaccine was assessed on Weeks 0, 6 and 12. Blood was sampled on Weeks 0, 2, 4, 8 and 12 to assess (1) lymphocyte proliferative response to PHA, concanavalin A (Con A), and pokeweed mitogen (PWM), (2) changes in peripheral blood mononuclear cell (PBMC) populations, (3) interleukin-2 (IL-2) production and (4) IgG and IgM production. After the completion of 12-week study, we continued to collect the blood weekly up to 17 weeks to evaluate the changes in immunoglobulin production upon first and second antigenic challenges on Weeks 13 and 15. Plasma lutein+zeaxanthin was undetectable in unsupplemented dogs but concentrations increased (P<0.05) rapidly on Week 2 in lutein-supplemented dogs. Thereafter, concentrations generally continued to increase in dose-dependent manner, albeit at a much slower rate. Dogs fed lutein had heightened DTH response to PHA and vaccine by Week 6. Dietary lutein increased (P<0.05) lymphocyte proliferative response to all three mitogens and increased the percentages of cells expressing CD5, CD4, CD8 and major histocompatibility complex class II (MHC II) molecules. The production of IgG increased (P<0.05) in lutein-fed dogs after the second antigenic challenge. Lutein did not influence the expression of CD21 lymphocyte marker, plasma IgM or IL-2 production. Therefore, dietary lutein stimulated both cell-mediated and humoral immune responses in the domestic canine.     

Cell-mediated immune response in cattle to bovine respiratory syncytial virus

Cattle inoculated with bovine respiratory syncytial virus (BRSV) were evaluated for the development of a cell-mediated immune response. Results of the leukocyte migration-inhibition test under agarose and the delayed hypersensitivity test indicated that a cell-mediated immune response was elicited after intranasal inoculation of calves with BRSV. Migration inhibition in the leukocyte migration-inhibition test was detected by postinoculation day (PID) 5 and reached maximum inhibition on PID 21. Inhibition of leukocyte migration was still evident by PID 42 when values were still appreciably greater than preinoculation values. All of the calves inoculated with BRSV developed a delayed hypersensitivity skin response when challenge exposed intradermally with BRSV antigen.     

Humoral and cell-mediated immune response to crude antigens of Dermatophilus congolensis during experimental infection of rabbits.

Rabbits were infected with Dermatophilus congolensis and tested for humoral immune response by indirect haemagglutination and for cell-mediated immune response to crude antigens of D. congolensis. Lymphocyte transformation and macrophage migration inhibition assays were used as in vitro correlates of cell-mediated immune response while cutaneous delayed hypersensitivity was used in vivo. Endo-antigen and whole cell antigen were found to significantly induce cell-mediated immune response. In contrast, humoral responses were found to be more significantly induced by exo-antigen. A biphasic immune response was revealed by the lymphocyte transformation test.     

Type 1 and type 2 immune response profiles of commercial dairy cows in 4 regions across Canada

Diseases of dairy cattle have adverse implications for both the dairy industry and animal welfare. Understanding adaptive immune response profiles of cattle on a national scale will provide insight into the potential for improving health and decreasing disease. The objectives of the present study were to evaluate immune response phenotypes of Holstein cows outside the peripartum period and to determine if antibody isotype bias to putative type 1 and type 2 test antigens is maintained. The cows, housed on commercial farms in 4 key dairy regions across Canada, were immunized with test antigens to measure their ability to mount cell-mediated immune responses (CMIR) and antibody-mediated immune responses (AMIR). Delayed-type hypersensitivity (DTH) was used as an indicator of CMIR and primary and secondary serum antibodies of the immunoglobulin (Ig) G1 and IgG2 isotypes were used to determine AMIR to the test antigens. Immune response phenotypes varied significantly among regions, herds, and cows. Cows in Alberta had significantly higher DTH responses and secondary responses to the type 2 test antigen than those in other regions. However, cows in Alberta had significantly lower primary antibody responses. It was found that Alberta had the lowest incidence of mastitis caused by Escherichia coli and Staphylococcus aureus compared with other regions. The IgG1/IgG2 antibody isotype ratio confirmed the nature of the test antigens. This was the first study to evaluate adaptive immune response profiles and disease incidence of dairy cows on a national scale and it therefore provides a glimpse of the current situation in Canada.     

Evaluation of bovine cutaneous delayed-type hypersensitivity (DTH) to various test antigens and a mitogen using several adjuvants

The Bacillus Calmette Guerin (BCG)-induced/purified protein derivative (PPD)-elicited tuberculin skin test is a reliable measure of cell-mediated immune response (CMIR), specifically delayed-type hypersensitivity (DTH); however, its use in livestock may confound diagnosis of Mycobacterium tuberculosis. Therefore, various alternative antigen/adjuvant combinations were evaluated as inducers of DTH that were compared to the BCG/PPD test system with the purpose of finding a skin DTH protocol that does not cross-react with the tuberculin test and allows identification of high and low CMIR responder phenotypes. Specifically, 30 non-lactating cows (five/treatment) were sensitized on day 0 with mycobacteria [BCG, M. tuberculosis or Mycobacterium phlei cell wall extract (MCWE)], and ovalbumin (OVA) emulsified in Freund's complete adjuvant (FCA), non-ulcerative Freund's adjuvant (NUFA), complete NUFA or MCWE. On day 21, cows were injected intradermally with various test antigens including PPD tuberculin, phlein, and OVA. Phosphate buffered saline was included as the negative control and the T-cell mitogen phytohemagglutinin (PHA) was also administered. Double skin-fold thickness was evaluated before and at 6, 24, and 48 h post-injection. Skin biopsies were taken at 24 and 48 h to assess oedema, necrosis, and inflammatory cell infiltration. BCG/PPD and M. phlei/phlein treatments when given with a Freund's adjuvant induced equivalent DTH with peak reactions at 24-48 h after antigen injection. Cows receiving NUFA had fewer injection site granulomas than FCA or CNUFA treatments. The change in skin thickness response to PHA peaked at 6 h. Only cows receiving mycobacteria in NUFA had skin response to OVA, which peaked 6-24 h post-injection. Only sites tested with PPD or phlein had significantly higher lymphocyte infiltration than control, whereas neutrophils were significantly higher at PHA test sites and eosinophils predominated at the PHA test sites. Macrophages were significantly more numerous at the PPD and/or phlein test sites in treatment groups that received killed mycobacteria in a Freund's adjuvant and/or with BCG, and at the PHA test sites in all treatment groups. It was concluded that the M. phlei/phlein system did induce DTH and was similar to the DTH induced by the BCG/PPD system when MCWE was administered with a Freund's adjuvant. Therefore, this protocol is suitable for detecting high/low CMIR responders in research herds. However, cross-reaction to PPD was evident following induction of DTH using M. phlei. Hence, this protocol does not alleviate the problem of artificial induction of DTH cross-reactivity and would not be suitable for commercial herds where tuberculin testing is required.     

Correlation between B-cell mitogenicity and immunosuppressor effects of a protein released by porcine monocytes infected with African swine fever virus

Virus-free supernatants of cultured swine monocytes infected by African swine fever virus (ASFV) suppressed in vitro proliferation of porcine and human blood mononuclear cells in response to phytohemagglutinin and the in vivo primary immune response of C57BL/6 mice against sheep RBC. The supernatants were fractionated by discontinuous ion-exchange chromatography and subfractionated by double-step preparative isoelectric focusing. The pool of the most purified active subfractions (F5'EP-ASFV) is made up of heat-unstable material, can be stained by silver nitrate, and has an isoelectric point of 3.88, a maximal optical density at 280 nm, and a mass of 36,000 daltons. In vivo kinetic studies in nonimmunized C57BL/6 mice were performed on days 1, 2, 3, 5, and 7 after injection with 50 micrograms of F5'EP-ASFV protein. Compared with the untreated mice, the treated mice had a noticeable increase in nonspecific immunoglobulin-secreting splenic plaque-forming cells (PFC) with the following isotype profile: IgG2a greater than IgG2b greater than IgG3 greater than IgG1 congruent to IgM. Three days after treatment with the active material, specific IgM PFC against sheep RBC increased up to 23-fold. In C57BL/6 mice immunized against sheep RBC 2 days after treatment with F5'EP-ASFV, the increase in nonspecific PFC was followed by a suppression of specific PFC response in the respective isotype. When C57BL/6 mice were treated after priming with sheep RBC, however, there was little or no suppression of specific PFC and the increase in nonspecific PFC was considerably lower than that in the other F5'EP-ASFV-treated mice. In this case, kinetic curves of specific vs nonspecific PFC of each isotype were mirror images. Mice treated with 200 micrograms of F5'EP-ASFV protein died with hemorrhagic diastasis.     

Immune responses of swine to oral inoculation with embryonated eggs of Ascaris suum

Responses of swine to oral inoculation with embryonated eggs of Ascaris suum were monitored, using lymphocyte blastogenesis assays, indirect radioimmunoassays, and peripheral eosinophil counts (EC). Transient cell-mediated immune responses of peripheral lymphocytes were detected by lymphocyte blastogenesis assay as early as postinoculation day (PID) 2, but were rarely positive for consecutive samples taken at 2-day intervals. Humoral antibodies were first detected at PID 6 to 17 by indirect radioimmunoassays in the various experiments. Positive cutaneous delayed hypersensitivity reactions were observed when pigs were tested at 6 to 7 weeks after inoculation. Histopathologic examination verified infiltration of lymphocytes into the lesions. The EC increased as early as PID 4 to 7 and showed a secondary increase after the 2nd oral inoculation of eggs to as high as 11,400/mm3 (44% of the total WBC). Subsequently, EC decreased rapidly 14 days after the last inoculation of eggs.     

Kinetics of the wattle reaction to human plasma

Human plasma produced cutaneous basophil hypersensitivity when injected into chicken wattles. The kinetics of the response development were affected by presensitization, whether or not complete Freund's adjuvant was used. Presensitized chickens developed their maximum response significantly sooner (12.6 hr earlier) than the controls.     

Migration-inhibition response of peripheral leukocytes to tuberculin in cats sensitized with viable Mycobacterium bovis (BCG).

Delayed hypersensitivity reactions to antigens injected intradermally are reported as not occurring in the cat. Cats infected with viable Mycobacterium bovis (BCG) organisms developed a transient migration-inhibition response of their leukocytes to tuberculin. The migration-inhibition response subsided in 6 weeks in spite of the persistance of viable BCG. Significant intradermal reactions to tuberculin 60 days after BCG injection did not occur. The response of the cat differs from that of many mammalian species in which strong in vivo and in vitro delayed hypersensitivity type reactions persist with mycobacterial infections. Despite the lack of continued measurable delayed hypersensitivity, the cat appears to have adequate resistance to mycobacterial infections.     

Turkey origin reovirus-induced immune dysfunction in specific pathogen free and commercial turkey poults

Recently, pathogenesis studies, using genetically distinct turkey-origin reoviruses (TRVs), revealed that poults infected with certain TRV isolates had moderate to severe bursal atrophy, suggesting virus-induced immune dysfunction. In order to characterize the effect of TRV infection on the turkey immune system, classical assays were undertaken to quantify the humoral and cell-mediated immune responses in small Beltsville and broad-breasted white poults infected with the TRV isolate NC/SEP-R44/03. A marked effect on the cutaneous basophil hypersensitivity response, and on the antibody response to Newcastle disease virus (NDV) exposure, was noted in commercial and specific pathogen free (SPF) poults inoculated with NC/SEP-R44/03 at three days of age. Moderate to severe bursal atrophy, similar to that noted previously in SPF poults, occurred in commercial poults inoculated at three days of age. This immune dysfunction and bursal atrophy was not present in commercial poults inoculated at three weeks of age.     

Immunomodulation in weanling swine with dietary selenium

The capability of dietary selenium (Se) to augment the immune response was evaluated in 96 crossbred weanling swine. Six groups of 16 pigs were fed diets with Se supplemented as sodium selenite at 0, 0.3, 0.6, 0.9, 1.2, and 1.5 mg/kg. The basal diet contained 0.068 mg of Se/kg. Weight gain, feed consumption, and feed efficiency were similar for all diets. Whole blood concentrations of Se linearly increased as the dietary concentrations of Se increased. The humoral response was monitored by immunoglobulin G titers to lysozyme and ribonuclease, using an enzyme-linked immunosorbent assay. Although no significant difference in immunoglobulin G titers to either antigen was detected among diets, a similar trend in antibody response was noted. The diet with 0.9 mg of added Se/kg produced the highest antibody response to both antigens, whereas the diet with 0.3 mg of added Se/kg produced the lowest titers for both antigens. Cell-mediated immunity was evaluated in the pigs by the dermal response to phytohemagglutinin. Significant difference was not detected in pigs fed the various diets in terms of the mean diameters of their dermal reactions to phytohemagglutinin injections. Although blood concentrations of Se were increased, rate and efficiency of weight gain and humoral and cell-mediated immunity were not significantly improved by adding 0.3 to 1.5 mg of Se/kg to diets.     

甲砜霉素中毒对肉仔鸡免疫器官损伤的病理学影响

4日龄AA+肉鸡304只,随机分为4组,分别以0(对照组)、500(Ⅰ组)、1 000(Ⅱ组)1、500(Ⅲ组)mg/kg饲料的甲砜霉素剂量饲喂6周,研究甲砜霉素对肉鸡免疫器官的病理学损害。试验开始后每天观察肉鸡的临床症状,每周称重1次计算平均体质量,分别在第2、4、6周测定红细胞数量、血红蛋白含量、免疫器官脏器系数,并取免疫器官作石蜡切片以研究甲砜霉素对肉鸡免疫器官的病理组织学影响。结果显示,对照组、Ⅰ组、Ⅱ组和Ⅲ组的死亡率分别为0%、9.21%、64.47%和68.42%;中毒鸡表现为食欲减退、体质量增长缓慢、贫血;法氏囊、脾脏和胸腺脏器系数显著降低,淋巴细胞减少。结果表明,即使以500 mg/kg饲料的甲砜霉素持续饲喂肉鸡,均可对肉鸡的免疫器官结构造成明显损伤,尤其是体液免疫器官,并且这种损伤存在剂量效应关系。     

Dietary phosphorus and an inflammatory challenge affect performance and immune function of weanling pigs

Ninety-six 3-wk-old pigs (6.3+/-0.12 kg initial BW) were allotted to one of eight treatments based on BW and litter origin to determine the effect of dietary phosphorus and an inflammatory challenge on performance and immune function. Four corn-soybean meal-based treatment diets were formulated to contain 0.16, 0.24, 0.32, or 0.40% available P. Monocalcium-dicalcium phosphate was used as the supplemental P source. The Ca:available P ratio was maintained at 2:1. To challenge the pigs, half of the pigs in each dietary treatment were injected i.m. with E. coli lipopolysaccharide (200 microg/kg of BW) on d 7 and 14. This resulted in a 2 x 4 factorial arrangement of treatments. Average daily gain for the 35-d study was increased linearly (P < 0.01) by increasing supplemental P. Average daily gain and ADFI were decreased (P < 0.05) by lipopolysaccharide injection. Serum P concentrations increased linearly (P < 0.01) with increasing supplemental P. Antibody titers to the injection of sheep red blood cells and ovalbumin on d 21 decreased linearly (P < 0.10) by increasing supplemental P. In vitro blastogenic response of lymphocytes to phytohemagglutinin (PHA) on d 25 was increased linearly (P < 0.05) by increasing supplemental P. Blastogenic response of lymphocytes to pokeweed mitogen on d 25 was not affected. On d 31, skinfold thickness 6 h following an intradermal injection of PHA was increased quadratically (P < 0.07) by increasing supplemental P. There were no P x lipopolysaccharide interactions for any immune response measure. In conclusion, increasing supplemental P increased ADG and enhanced cell-mediated immune response but decreased humoral immune response.     

In vivo and in vitro responses of cats sensitized with viable Mycobacterium bovis (BCG).

Cats were injected subcutaneously with viable Mycobacterium bovis (BCG), and immune responses were evaluated at various times after injection. The BCG injection produced fever, leukocytosis, neutrophilia, and lymphadenopathy of regional lymph nodes. Intradermal tuberculin injection produced responses consistent with delayed type hypersensitivity reaction in the treated cats at postinoculation day 21. Skin responses to tuberculin were not significant at postinoculation day 49. The cellular infiltrate at the tuberculin injection site at 48 hours after injection was an admixture of polymorphonuclear cells and mononuclear cells. The BCG produces strong intradermal skin responses in the cat, but the response was not long-lived as in cattle and guinea pigs. The BCG injection did not produce significant changes in the absolute total lymphocyte and absolute T-lymphocyte numbers in peripheral blood. The percentage of T-lymphocytes was significantly higher in the BCG-treated group. Differences were not observed in lymphocyte blastogenesis with tuberculin and non-specific mitogens between BCG-treated and control cats.