Peanut and Amaranthus leucocarpus lectins discriminate between memory and naive/quiescent porcine lymphocytes

Lectins are relevant tools to isolate and characterize different cellular sub-populations. In this work, we used the lectins Arachis hypogaea (Peanut agglutinin, PNA) and Amaranthus leucocarpus (ALL), specific for Galss1, 3GalNAc, to characterize naive and memory lymphocytes from pigs, experimentally infected with the porcine rubulavirus (RvP). Our results showed that both lectins recognized preferentially lymphocytes with the CD4(+)CD8(+) phenotype (P<0.05). The phenotypic analysis of the cells recognized by these lectins indicated that PNA(+) lymphocytes showed higher rate of the CD29 antigen (PNA(+)CD29(high)) than ALL(+) (ALL(+)CD29(low)). The number of PNA(+)CD29(high) lymphocytes increased after 8 weeks of experimental infection with RvP, and most of the ALL(+)CD29(low) cells became CD29(middle). PNA(+) lymphocytes isolated from infected pigs proliferated after stimulation with the RvP, whereas ALL(+) cells did not. In vitro assays indicated that the ALL(+) cells from previously infected pigs diminished from 7.5 +/- 2 to 0.5 +/- 0.3% after RvP stimulation; whereas PNA(+) cells increased from 4 +/- 1 to 42 +/- 2%, whereas no modification in ALL(+) or PNA(+) cellular population was identified in lymphocytes from naive animals after RvP stimulation. Our results suggest that the cellular distribution/organization of the O-glycosydically linked glycans on lymphocytes may correlate with biological functions, and that PNA could be a tool to isolate specifically porcine memory T cell subsets, whereas ALL could be useful to isolate naive/quiescent T lymphocytes.     

Functional characterization of a swine CD4(+)/CD8(+) double positive lymphoblastoid T-cell line with a CD25(+)/CD45RA(-) phenotype generated in vitro with interleukin-2

A dual expressing (CD4(+)/CD8(+)) porcine lymphoblastoid T-cell line (pIL-2d) generated from peripheral blood mononuclear (MN) cells shown to be highly responsive to exogenous interleukin-2 (IL-2) was characterized. The swine MN cells were initially stimulated with concanavalin A (Con A), and sub-passaged using decreasing amounts of conditioned medium (CM), which was prepared from culture fluids of Con A activated porcine MN cells, until a steady growth was observed. The resulting pIL-2d cells require exogenous IL-2 from CM and are highly responsive to recombinant human IL-2 (rhIL-2). The pIL-2d cells exhibited a specific, dose-dependent proliferative response to stimulation with IL-2. The specificity of this proliferative response was confirmed to be IL-2 induced by its inhibition with an anti-swine IL-2 receptor (alpha-swIL-2R) monoclonal antibody (mAb). Furthermore, the pIL-2d cells are highly responsive to exogenous IL-2 contained in culture fluids derived from antigen-driven blastogenic tests performed with lymphocytes of vaccinated swine. This property makes the pIL-2d cells an ideal functional adjunct to immunochemical or molecular tests that are commonly used to measure total porcine IL-2. Interestingly, the phenotype of the pIL-2d cells after five or more passages was shown by flow cytometric analysis to be CD4(+)/CD8(+)/CD45RA(-)/CD25(+) and to remain unchanged thereafter. Although, the mechanism of selection and maintenance of the CD4(+)/CD8(+) DP cells developed here remains unclear, our data suggest that an oligoclonal or polyclonal expansion and maintenance of cells of this phenotype was mediated by exogenous IL-2.     

Differential cytokine gene expression in CD4+ and CD8+ T cell subsets of calves

The distinct patterns of cytokine expression in CD4+ and CD8+ T cells are well understood in mice and humans. However, little information is available about cytokine expression in bovine CD4+ and CD8+ T cells. In this study, mRNA expression of 19 different cytokines was analyzed in CD4+ and CD8+ T cells of calves with or without Concanavalin A (Con A) stimulation. CD4+ and CD8+ T cell populations were enriched to 98% purity by positive selection using magnetic cell sorting (MACS). CD4+ T cells spontaneously expressed the mRNAs of interleukin-1alpha (IL-1alpha), IL-1beta, IL-2, IL-6, IL-7, IL-8, IL-10, IL-18, IFN-gamma, TNF-alpha, TNF-beta and TGF-beta, and augmented the mRNA expression of IL-10, IFN-gamma and TNF-beta after Con A stimulation. The mRNAs of IL-3, IL-4, IL-5, IL-13 and GM-CSF were newly expressed in Con A-stimulated CD4+ T cells. CD8+ T cells displayed spontaneous mRNA expression of IL-6, IL-18, TNF-alpha, TNF-beta and TGF-beta, and newly expressed the mRNA of IL-2, IL-7, interferon-gamma (IFN-gamma) and GM-CSF after Con A stimulation. It was found that CD4+ T cells expressed the mRNA of 17 cytokines except for IL-12 and IL-15, while CD8+ T cells expressed only the mRNA of 9 cytokines after Con A stimulation. The profile of cytokine mRNA expression was substantially different in the CD4+ and CD8+ T cells of calves, indicating that CD4+ T cells can be distinguished from CD8+ T cells by the cytokine gene expression of IL-1alpha, IL-1beta, IL-3, IL-4, IL-5, IL-8, IL-10 and IL-13. Differential cytokine expression between CD4+ and CD8+ T cells serve to interpret an individual function of T cell subsets in the immune system of calves.     

传染性法氏囊病病毒超强毒感染SPF鸡免疫器官中CD4+和CD8+T淋巴细胞动态分布

利用免疫组织化学染色对传染性法氏囊病病毒（IBDV）超强毒LX株感染SPF鸡免疫器官中CD4^ 和CD8^ T淋巴细胞的动态分布进行了研究。超强毒LX株接种2周龄SPF雏鸡，在其法氏囊、脾脏、胸腺、盲肠扁桃体、骨髓和哈氏腺中均可检出IBDV抗原的存在和CD4^ 与CD8^ T淋巴细胞的数量改变。在法氏囊中，CD4^ 淋巴细胞主要存在于淋巴滤泡间隙和滤泡皮质，而CD8^ T淋巴细胞则丰在于整个淋巴滤泡和滤泡间隙，并且CD8^ T淋巴细胞数量明显多于CD4^ T淋巴细胞，在接种后14d仍未见CD4^ 和CD8^ T淋巴细胞数量减少。脾脏中CD4^ T淋巴细胞主要存在于外周小动脉淋巴鞘或散在，而CD8^ T淋巴细胞则多存在于外周小动脉淋巴鞘和红髓。接种后胸腺中CD4^ 和CD8^ T淋巴细胞在皮质中减少，但在髓质增多，尤其是CD8^ T淋巴细胞数明显多于CD4^＋T淋巴细胞。盲肠扁桃体中CD4^ 和CD8^ T淋巴细胞主要存在于发生中心，尤其是CD8^ T淋巴细胞数比CD4^ T淋巴细胞明显多。骨髓和哈氏腺中也可见CD4^ 和CD8^ T淋巴细胞，而且CD8^ T淋巴细胞更多。在这些淋巴器官中，病毒损伤部位出现CD4^ 和CD8^ T淋巴细胞的迁入聚集，表明T淋巴细胞可能参与IBDV超强毒的免疫致病过程。     

CD4+CD25+ regulatory T cells are infected and activated during acute FIV infection

HIV-induced AIDS may be mediated by the activation of immunosuppressive CD4+CD25+ T regulatory cells (Treg cells). Treg cells have been shown to regulate CD4+ and CD8+ immune responses to HIV and FIV antigens in vitro. We tested the hypothesis that Treg cells become infected and activated during the acute infection with FIV leading to the suppression of CD4+ T helper cell responses. Cats were experimentally infected with FIV-NCSU1 and blood and lymph node cells were collected at weekly intervals following inoculation. Real-time RT-PCR was used to determine plasma viremia and the relative expression of FIV, FoxP3, TGF-beta, and GAPDH mRNA copies in CD4+CD25+ and CD4+CD25- T cell subsets. Flow cytometry was used to assess the absolute numbers of each cell type and the expression of surface TGF-beta and intracellular FoxP3 in CD4+CD25+ and CD4+CD25- T cells at each time-point. Treg suppression of IL-2 production in CD4+ T helper cells was assessed by ELISPOT assays. Our results showed that peak viremia occurred at 2 weeks post infection and correlated with maximal infectivity in CD4+CD25+ T cell populations. FIV-gag-mRNA levels were higher in CD4+CD25+ T cells than CD4+CD25- T cells throughout the acute phase of infection. Induction of FoxP3 and TGF-beta indicated activation of Treg cells during the acute stage infection, which was confirmed by Treg cell suppression of IL-2 production by CD4+ Th cells in an ELISPOT assay. Our findings support the hypothesis that early activation of Treg immunosuppressor function may limit an effective anti-FIV response, contributing to the establishment of chronic infection and the immunodeficiency caused by this virus.     

禽网状内皮组织增生病病毒感染对SPF雏鸡血液和局部淋巴组织CD4+/CD8+细胞及相关细胞因子表达的影响

旨在探讨禽网状内皮组织增生病病毒（reticuloendotheliosis virus,REV）对SPF雏鸡血液和局部淋巴组织中T淋巴细胞数量以及相关细胞因子表达的影响。将96只1日龄SPF雏鸡随机分为REV感染组和对照组,应用流式细胞术、酸性α-醋酸萘酯酶染色（acid α-naphthyl acetate esterase,ANAE）、荧光定量PCR等方法对上述指标进行检测。试验数据表明,与对照组相比,感染组雏鸡血液CD4⁺T淋巴细胞数量在第7~35天显著降低、CD8⁺T淋巴细胞数量在第7~28天显著升高,CD4⁺/CD8⁺比值在第7~28天显著降低（均P<0.05或P<0.01）;局部淋巴组织哈德尔腺（Hader’s gland,HG）、派伊尔结（Peyer’s patch,PP）和盲肠扁桃体（caecal tonsil,CT）中ANAE⁺T淋巴细胞数量均显著降低（均P<0.05或P<0.01）;GH、PP和CT中细胞因子IL-2、IFN-γ和TNF-α 转录量都有不同程度升高。本研究表明,REV感染引起雏鸡血液中CD4⁺ T淋巴细胞数量降低、CD4⁺/CD8⁺T淋巴细胞比例失衡、局部淋巴组织中T淋巴细胞数量相对减少及细胞因子TNF-α转录持续升高与REV造成感染雏鸡细胞免疫功能显著降低密切相关。     

CD56 is expressed exclusively on CD3+ T lymphocytes in canine peripheral blood

CD56+ cells in canine blood leukocytes were characterized by flow-cytometric analysis of peripheral blood of 30 healthy adult beagle-dogs (15 males and 15 non-pregnant females). In 19 of the 30 dogs, anti human CD56 antibody, Leu-19, reacted with 8.8-21.7% of peripheral blood lymphocytes. All CD56+ cells simultaneously expressed CD3 molecules on their surface. Further phenotypic analysis revealed that 50.6+/-13.1% of the CD56+ cells showed CD4-CD8+ phenotype and 43.7+/-10.1% showed CD4+CD8- phenotype. Expression intensity of CD56 on the CD4-CD8+CD56+ cells was significantly higher than that on CD4+CD8-CD56+ cells (P<0.001). These findings indicate that CD56, which is a neural cell adhesion molecule, is uniquely expressed on subsets of T lymphocytes in canine peripheral blood.     

Reduction of CD4+ and CD8+ T lymphocytes during febrile periods in horses experimentally infected with equine infectious anemia virus

Three horses were experimentally infected with equine infectious anemia virus (EIAV). All horses were febrile after inoculation with EIAV and then developed chronic symptoms with intermittent fever. The febrile period was characterized by a rise in body temperature with reduced PBL and erythrocyte counts. Flow cytometric analysis showed that the reduced number of lymphocytes was due to significant decreases in CD4+ and CD8+ T cells in the absence of any change in B cell number. At the end of the febrile period the body temperature began to recover and numbers of CD4+ and CD8+ T cells showed a tendency to increase. For CD8+ T cells, this increase continued for several days after the febrile period. B cell number also significantly increased after the febrile period in two out of three horses. The decrease of CD8+ T cells was greater than that of CD4+ T cells. Although the PBL numbers and the CD4/CD8 ratio returned to the level of the preinoculation period, erythrocyte numbers decreased as the body temperature normalized after each intermittent fever. These results suggest that the recurring cycle of fever accompanied with viremia is caused by a reciprocal relationship between EIAV replication and the host immune response. Furthermore, we demonstrate that the lymphocytic response mitigates fever and viremia in EIAV infection despite the absence of virus neutralizing antibody.     

Role of CD4+, CD8+ and double negative T-cells in the protection of SCID/beige mice against respiratory challenge with Rhodococcus equi.

To evaluate the contributions of T-lymphocyte subsets in pulmonary immunity against Rhodococcus equi, C.B-17 SCID/beige mice were adoptively transferred with splenic lymphocytes from congenic BALB/c mice previously infected with R. equi. Spleen cells were enriched for either CD4+ or CD8+ populations before inoculation, Flow cytometry showed that each enriched population contained less than 0.5% cross contamination. Groups of adoptively transferred SCID/beige mice were sacrificed 6 and 13 d after intranasal infection with R. equi. Bacterial clearance was measured in the lungs, liver and spleen. Lesion development was assessed by gross and histopathological score and the fate of transferred cells assessed by flow cytometry and by immunohistochemistry. SCID/beige mice receiving either CD4+ or CD8+ T-cells were able to clear the infection better than control mice. On d 6 post-infection, bacterial numbers were significantly lower in the lungs of CD4+ transferred mice as compared to CD8+ mice. By d 13, both groups had cleared R. equi from all organs. CD4+ cells were however identified in the lung and spleen of CD8+ recipients at d 13 making conclusions about the role of CD8+ cells in R. equi clearance impossible. By contrast, no significant increases in CD8+ lymphocytes were observed in the organs of CD4+ recipients. All mice developed suppurative bronchopneumonia but lesions were most severe in the CD4+ group. Immunohistochemistry and flow cytometry confirmed that CD4+ and CD8+ cells had migrated to the lungs of adoptively transferred mice. Serum antibody against R, equi was not detected by ELISA in the recipients. SCID/beige mice receiving CD4-CD8- cells were unable to clear R. equi. The study supports the suggestion that CD4+ cells have a central role in R. equi clearance in mice.     

Changes in Distribution and Numbers of CD4+ and CD8+ T‐lymphocytes in Lymphoid Tissues and Intestinal Mucosa in the Early Phase of Experimentally Induced Early Onset Mucosal Disease in Cattle

Mucosal disease (MD), one sequelae of bovine virus diarrhoea virus (BVDV) infection, causes severe lesions in lymphoid tissues and mucosal surfaces. Lesions are associated with the presence of cytopathogenic (cp) BVDV and initially characterized by apoptotic cell death. The objective of this investigation was to determine if this cell death is mediated only by the cp BVDV, which is known to induce apoptosis in cell culture or if immune‐mediated host reactions might also contribute. Early onset MD was experimentally induced in calves by inoculation of persistently viremic calves with a closely related cp BVDV. Calves were euthanized in the early phase of infection between days 5 and 13 post‐inoculation and tissues from tonsils, lymph nodes, Peyer's patches, jejunum and colon were collected. Presence of cp BVDV antigen was correlated with distribution of lymphocyte subpopulations in consecutive cryostat sections. In the lymphoid tissues, cp BVDV antigen was predominantly found in the lymphoid follicles. The increase of infected cells with time post‐inoculation was paralleled by a decrease of B‐lymphocytes and an increase of CD4+ T‐lymphocytes. An increased number of CD8+ T‐lymphocytes was seen in progressed lesions only. In the intestinal mucosa, initially multifocal, later diffuse infection with cp BVDV was accompanied by a multifocal or diffuse increase of CD4+ T‐lymphocytes, respectively. Numbers of IgA+ plasma cells and CD8+ T‐lymphocytes were decreased. The common change observed in lymphoid tissues and mucosa was the increase of CD4+ T‐lymphocytes in sites with lesions. This might indicate a cell‐mediated immune response to the cp BVDV. Besides their helper function to other cells of the immune system, activated CD4+ T‐lymphocytes might also exert cytotoxic activity, induce apoptosis in target cells via Fas/Fas ligand binding and thus contribute to the severity of tissue lesions in MD.     

Immunization-induced decrease of the CD4+:CD8+ ratio in cats experimentally infected with feline immunodeficiency virus.

In a previous experiment a group of 15 specified pathogen free (SPF) cats were experimentally infected with a Swiss isolate of feline immunodeficiency virus (FIV). A group of 15 SPF cats served as FIV negative controls. Nine cats of each group were vaccinated with a recombinant feline leukemia virus (FeLV) vaccine, six cats in each group with a placebo vaccine. All vaccinated cats developed high antibody titers to FeLV and were protected against subsequent FeLV challenge infection. In both control groups five of six cats became persistently infected with FeLV. Unexpectedly, the primary immune response to the vaccine antigen was significantly higher in the FIV positive group than in the FIV negative. The secondary response was stronger in the FIV negative cats. The goal of the present investigation was to further study the immune response in these 30 cats. They were immunized twice with the synthetic peptide L-tyrosine-L-glutamic acid-poly(DL-alanine)-poly(L-lysine) (TGAL) 21 days apart. Blood samples were collected on four occasions during the immunization process. They were tested for antibodies to TGAL, complete blood cell counts and CD4+, CD8+ and pan-T-lymphocyte counts. The following observations were made: (1) in contrast to the FeLV vaccine experiment, the primary immune response to TGAL was not significantly stronger in the FIV positive cats when tested by enzyme-linked immunosorbent assay (2). The absolute size of the CD4+ lymphocyte population was distinctly smaller in the FIV positive than in the FIV negative cats. The lowest CD4+ values were found in the dually FIV/FeLV infected cats. (3) A population of CD8+ lymphocytes was identified that was characterized by a distinctly weaker fluorescence. The size of this population increased in FIV positive and decreased in FIV negative cats during the TGAL immunization experiment. (4) The CD4+:CD8+ ratio increased in FIV negative cats during TGAL immunization from 1.9 to 2.3. In contrast, in FIV positive animals the CD4+:CD8+ ratio decreased significantly from 1.9 to 1.3 during the same period. From these and earlier data it was concluded that in short-term FIV infection the immune response to T-cell dependent antigens may be increased over that of the controls. Immune suppression develops gradually with duration of the infection. The significant drop of the CD4+:CD8+ ratio over a 5 week immunization period suggests that antigenic stimulation may accelerate the development of immune suppression in FIV positive cats. If this is a general feature, FIV infection may provide a particularly interesting model for studying the pathogenesis of AIDS.     

Characterization of immune modulating functions of γδ T cell subsets in a gnotobiotic pig model of human rotavirus infection

We characterized immune modulating functions of porcine γδ T cell subsets in rotavirus infection using a gnotobiotic pig model of human rotavirus infection and sort-purified lymphocyte autologous co-cultures. We demonstrated that CD2+CD8- and CD2-CD8- γδ T cells have mainly pro-inflammatory function as evident by directly secreting IFN-γ or promoting CD4+ αβ T cell proliferation and IFN-γ production, whereas CD2+CD8+ γδ T cells mainly exert regulatory T cell function by expressing FoxP3, secreting IL-10 and TGF-β or increasing IL-10 and TGF-β production by CD4+ αβ T cells. γδ T cells responded to rotavirus infection by increasing TLR2, TLR3, TLR9 expression and IFN-γ and/or TGF-β production. The CD8- subsets likely differentiate into CD8+ subset by acquiring CD8 expression, explaining in part the apparently dual functions of CD2+CD8+ and CD2+CD8- subsets. Thus, both CD8+ and CD8- γδ T cell subsets can contribute to anti-rotavirus immunity and to the maintenance and restoration of intestinal and systemic homeostasis.     

The Localization Changes of CD4+ and CD8+ T Lymphocytes in Chicken Lung at Different Ages

The aim of this study was to investigate the immune state of chicken lung in different periods.With lung tissue of Hy-line White chicken at different ages,the distribution and quantity changes of CD4⁺ and CD8⁺T lymphocytes in lung were studied using immunohistochemistry staining.The results showed that CD8⁺T lymphocytes appeared firstly in embryonic at 18 d,while CD4⁺T lymphocytes appeared at 1-day-old chicken.At 4-day-old,there were aggregates of lymphocytes at the junction of the primary and secondary bronchi,which formed obvious broncho-associated lymphoid tissue (BALT).CD4⁺T lymphocytes of each age mainly occupied the central area of BALT,while CD8⁺T lymphocytes mainly surrounded the periphery.Since 56 days old,CD8⁺T lymphocytes are distributed in the inner wall of third-order bronchial airway,atrial septum,gas exchange area and interlobular connective tissue,and are distributed throughout the lung.In terms of quantity change,with the growth of daily age,the number of CD4⁺T lymphocytes and CD8⁺T lymphocytes gradually increased,and the number of CD4⁺ T lymphocytes was more than that of CD8⁺ T lymphocytes before 35 days of age,while the number of CD8⁺ T lymphocytes was significantly more than that of CD4⁺ T lymphocytes at the same age thereafter.The results showed that the distribution and number of CD4⁺ and CD8⁺T lymphocytes in the lungs of chickens were correlated with the age,and the changes could reflect that the lungs before the age of 35 days were dominated by humoral immunity,while the lungs after that tended to be cellular immunity.     

An engineered anti-idiotypic antibody-derived killer peptide (KP) early activates swine inflammatory monocytes,CD3+CD16+ natural killer T cells and CD4+CD8α+ double positive CD8β+ cytotoxic T lymphocytes associated with TNF-α and IFN-γ secretion

This study evaluated the early modulation of the phenotype and cytokine secretion in swine immune cells treated with an engineered killer peptide (KP) based on an anti-idiotypic antibody functionally mimicking a yeast killer toxin. The influence of KP on specific immunity was investigated using porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2) as ex vivo antigens. Peripheral blood mononuclear cells (PBMC) from healthy pigs were stimulated with KP and with a scramble peptide for 20 min, 1, 4 and 20 h or kept unstimulated. The cells were analyzed using flow cytometry and ELISA. The same time-periods were used for KP pre-incubation/co-incubation to determine the effect on virus-recalled interferon-gamma (IFN-γ) secreting cell (SC) frequencies and single cell IFN-γ productivity using ELISPOT.KP induced an early dose-dependent shift to pro-inflammatory CD172α⁺CD14^+high monocytes and an increase of CD3⁺CD16⁺ natural killer (NK) T cells. KP triggered CD8α and CD8β expression on classical CD4⁻CD8αβ⁺ cytotoxic T lymphocytes (CTL) and double positive (DP) CD4⁺CD8α⁺ Th memory cells (CD4⁺CD8α^+low CD8β^+low). A fraction of DP cells also expressed high levels of CD8α. The two identified DP CD4⁺CD8α^+high CD8β^+low/+high CTL subsets were associated with tumor necrosis factor alpha (TNF-α) and IFN-γ secretion. KP markedly boosted the reactivity and cross-reactivity of PRRSV type-1- and PCV2b-specific IFN-γ SC. The results indicate the efficacy of KP in stimulating Th1-biased immunomodulation and support studies of KP as an immunomodulator or vaccine adjuvant.     

The presence of CD25 on bovine WC1+ gammadelta T cells is positively correlated with their production of IL-10 and TGF-beta, but not IFN-gamma

WC1+ cells in cattle exhibit both regulatory and effector activities. However, it has not been elucidated whether they are so plastic that both activities co-exist in one cell or there are separate subpopulations of effector and regulatory cells. Since the production of IFN-gamma and IL-10 seems to be related to WC1+ cells' effector and regulatory function, respectively, the main aim of this study was to determine whether those cytokines are produced by separate subpopulations of WC1+, or are co-produced by the same cells. Due to increasingly frequent emphasised role of consumption of IL-2 in the mechanism of suppressor action of mouse CD25+CD4+ T regulatory cells, expression of the receptor's alpha chain for interleukin 2 (CD25) on WC1+ lymphocytes has been evaluated. An average of 5.21% of WC1+ cells obtained from PBMCs of 12-month-old heifers show constitutive expression of the CD25 molecule, with CD25(high)WC1+ and CD25(low)WC1+ cells accounting for 1.05% and 4.10% of WC1+ lymphocytes, respectively. For detection of intracellular cytokine production, PBMCs were stimulated with concanavalin A. Both IFN-gamma(-) and IL-10-producing cells within the CD25(-)WC1+ and CD25+WC1+ subpopulations were mainly separate subpopulations. The average percentage of IFN-gamma(+)IL-10(-), IFN-gamma(-)IL-10+ and IFN-gamma(+)IL-10+ cells among CD25(-)WC1+ lymphocytes was 4.03%, 2.67% and 0.51%, respectively. A positive correlation was observed between the presence of the CD25 molecule on WC1+ lymphocytes and production of IL-10 and TGF-beta, because the average percentage of IFN-gamma(-)IL-10+ and IFN-gamma(+)IL-10+ among CD25+WC1+ lymphocytes was 3 and 4.5 times higher as compared to the corresponding cells in the CD25(-)WC1+ subpopulation, whereas the percentage of IFN-gamma(+)IL-10(-) cells in both the subpopulations was not significantly different. The percentage of TGF-beta+ cells within the CD25+WC1+ subpopulation was 2.72 times as high as that of CD25(-)WC1+ lymphocytes. Therefore, with respect to the production of IFN-gamma, IL-10 and TGF-beta, CD25+WC1+ lymphocytes turn out to have a more suppressor profile than CD25(-)WC1+.     

CD4+ and CD8+ T- lymphocytopenia in a filly with Pneumocystis carinii pneumonia

Decreased proportion of CD4+ and CD8+ T lymphocytes in peripheral blood likely contributed to susceptibility to Pneumocystis carinii in a foal. Cytological evaluation of bronchoalveolar lavage was required for identification of the pathogen and serial flow-cytometric analysis of peripheral blood lymphocytes documented transient low expression of CD4+ and CD8+ T lymphocytes. Although immunodeficiency is uncommon, it must be included in the differential diagnosis for patients suffering from chronic or opportunistic infections and may provide an indication for immunostimulant therapy.     

Early hepatic immune response in rats infected with Fasciola hepatica

We investigated the phenotype of the T cells (CD4+ and CD8+) that produced Th1 (IFN-gamma) and Th2 cytokines (IL-4 and IL-10) during the firsttwo weeks of experimental fasciolosis in rats. We also followed the kinetics of the cytokine and proliferative responses of hepatic mononuclear cells (HMNC) over the same period. We found that HMNC were more numerous in the infected animals than in the controls. The percentage of CD4+ cells increased significantly after infection, whereas the percentage of CD8+ cells did not change. Moreover, the frequency of the cells producing (CP) cytokine changed after infection. The frequency of CP IFN-gamma on 7 days postinfection (pi) was similar to that in control animals. However, the frequency of CP IFN-gamma was clearly lower on day 14 pi, whereas the frequency of CP IL-4 and CP IL-10 had increased. The CP IL-10-were mostly CD4+. Mitogenic stimulation (phorbol myristate acetate/ionomycin) of HMNC led to an increase in the amounts of the Th2 cytokines in the supernatant on days 7 and 14 pi, with the increase more pronounced on day 14. In contrast, IFN-gamma levels also increased by day 7 pi but then decreased to below control levels by day 14. In addition, HMNC proliferation in response to mitogen followed a similar pattern to IFN-gamma production. These findings suggested that, during the first 2 weeks of infection, F hepatica induced a transient ThO cytokine profile followed by downregulation of the cellular response and the induction of a Th2 cytokine profile.     

Malignant catarrhal fever induced by Alcelaphine herpesvirus 1 is characterized by an expansion of activated CD3+CD8+CD4- T cells expressing a cytotoxic phenotype in both lymphoid and non-lymphoid tissues

ABSTRACT: Alcelaphine herpesvirus 1 (AlHV-1) is carried by wildebeest asymptomatically. It causes a fatal lymphoproliferative disease named wildebeest-derived malignant catarrhal fever (WD-MCF) when cross-species transmitted to a variety of susceptible species of the Artiodactyla order. WD-MCF can be reproduced experimentally in rabbits. In a previous report, we demonstrated that WD-MCF induced by AlHV-1 is associated with a severe proliferation of CD8+ T cells in the lymphoid tissues. Here, we further studied the mononuclear leukocytic populations in both the lymphoid (throughout the infection and at time of euthanasia) and non-lymphoid (at time of euthanasia) organs during WD-MCF induced experimentally in rabbits. To reach that goal, we performed multi-colour flow cytometry stainings. The results obtained demonstrate that the development of WD-MCF correlates in peripheral blood with a severe increase of CD8+ cell percentages; and that CD3+CD8+CD4- T cells were the predominant cell type in both lymphoid and non-lymphoid organs at time of euthanasia. Further characterization of the mononuclear leukocytes isolated from both lymphoid and non-lymphoid tissues revealed that the CD8+ T cells express high levels of the activation markers CD25 and CD44, produce high amount of gamma-interferon (IFN-γ) and perforin, and showed a reduction of interleukin-2 (IL-2) gene expression. These data demonstrate that the development of WD-MCF is associated with the expansion and infiltration of activated and cytotoxic CD3+CD8+CD4- T cells secreting high amount of IFN-γ but low IL-2.