Lymphocyte subpopulations in peripheral blood of lambs experimentally infected with bovine respiratory syncytial virus

The lymphocyte subpopulations of peripheral blood of normal lambs and lambs experimentally infected with bovine respiratory syncytial virus (RSV) were analysed by flow cytometry, using a panel of monoclonal antibodies against specific lymphocyte epitopes. Experimental infection with bovine RSV was characterized by a significant rise in SBU-T8+ (CD8+ or cytotoxic) T cells and a significant reduction in SBU-T4+ (CD4+ or helper) T cells and B (LCA p220+) lymphocytes (P less than 0.05). The helper/suppressor (CD4/CD8) ratio was reduced from 3.91 on the day of experimental infection to 1.13 on 10 days after experimental infection (P less than 0.001). The total number of SBU-T4+ (CD4+) and B cells returned to pre-inoculation values 14 days after experimental infection but the helper/suppressor ratio remained depressed up to 21 days post-inoculation.     

Lymphocyte subpopulations in peripheral blood of sheep experimentally infected with tick-borne fever.

The lymphocyte subpopulations in the peripheral blood of normal sheep and sheep experimentally infected with Cytoecetes phagocytophila, the causative agent of tick-borne fever, were analysed by flow cytometry, using a panel of monoclonal antibodies against specific lymphocyte epitopes. Experimental infection with tick-borne fever was characterised by a significant reduction in the total number of circulating lymphocytes six days after experimental infection (P less than 0.001). This lymphocytopenia was associated with a significant reduction in the number of B (LCAp220+) and T (CD5+) lymphocytes (P less than 0.001) but there was a significant increase in the number of cells which were neither T nor B (CD5-LCAp220-) cells (P less than 0.01). The reduction in the number of T lymphocytes was due to reduced numbers of circulating CD4+ (helper) T cells, CD8+ (cytotoxic/suppressor) T cells and those with the pan T cell marker (CD5+) but without CD4 or CD8 epitopes (CD4-CD8-). All lymphocytes returned to preinoculation levels 13 to 16 days after experimental infection.     

Depression of lymphocyte responses to phytohaemagglutinin in lambs experimentally infected with bovine respiratory syncytial virus.

Eight lambs were experimentally infected with bovine respiratory syncytial virus (BRSV) and the responses of their peripheral blood lymphocytes to the mitogen phytohaemagglutinin and BRSV antigen compared with that of control lambs injected with tissue culture fluid. The lymphocyte transformation responses to phytohaemagglutinin were significantly reduced five and 10 days after experimental infection with BRSV (P less than 0.05). It appears that these reductions were associated with CD4+ lymphocytes because CD4-enriched lymphocytes obtained five days after infection had more significantly reduced responses to phytohaemagglutinin than those obtained from the same group before infection and from the control group five days after inoculation (P less than 0.01). There were no significant lymphocyte transformation responses to BRSV antigen in both groups of lambs up to 21 days after inoculation (P greater than 0.05).     

Reinfection of lambs with bovine respiratory syncytial virus.

Eight lambs which were experimentally infected with bovine respiratory syncytial virus (RSV) when they were six to eight weeks old were challenged with the same virus seven months later. After reinfection, lambs developed mild clinical disease and the virus was isolated from nasal swabs from three lambs and peripheral blood from two lambs. Reinfection resulted in changes in peripheral blood cell populations. There was an early increase in the number of CD8+ T lymphocytes and B (LCA p220+) lymphocytes but the proportions of CD4+ and CD4-CD8- T lymphocytes were significantly reduced. Peripheral blood mononuclear cells obtained from lambs reinfected with bovine RSV showed significantly higher responses to bovine RSV antigen in vitro than those obtained from control lambs but their responses to the mitogen phytohaemagglutinin were significantly lower than in control lambs. RSV-specific IgG, IgM and IgA levels of serum samples obtained 10 days after challenge were significantly higher than those of serum samples obtained before challenge.     

T lymphocyte subset alterations following bluetongue virus infection in sheep and cattle

To determine potential mechanisms of differential disease expression in ruminants infected with bluetongue virus (BTV), clinically normal, BTV-seronegative, yearling sheep and cattle were infected subcutaneously with a standardized insect-source inoculum of BTV serotype 17 (BTV-17) (three infected and one contact control each) or animal adapted BTV serotype 10 (BTV-10) (three sheep only). BTV was isolated from peripheral blood cell components of infected sheep and cattle and all infected animals showed evidence of seroconversion by 14 days post infection (PI). Sheep infected with both serotypes of BTV developed pyrexia, oral lesions, and leukopenia which were most severe on days 7-8 PI. Analysis of peripheral blood mononuclear leukocytes with specific monoclonal antibodies and flow cytometry revealed panlymphocytopenia on day 7 PI. This response was further characterized by an increase in the CD4/CD8 ratio (greater than 3) resultant from a greater decrease in absolute numbers of circulating SBU-T8(CD8+) ("cytotoxic/suppressor") lymphocytes compared to SBU-T4 (CD4)+ ("helper") lymphocytes. SBU-T19+ lymphocytes were also decreased below baseline values on days 5-14 post infection. On day 14 PI there were increased CD8+ lymphocytes and decreased CD4/CD8 ratios (approximately 0.6) in these sheep. Clinical and hematologic changes in cattle infected with BTV-17 were minimal and consisted of mild pyrexia (rectal temperature 103 degrees F) on day 9 PI in two of three infected animals and mild leukopenia on several days PI in one animal. This leukopenia was the result of a pan T lymphocytopenia with CD4/CD8 ratios in the expected range (1-2). Similar to infected sheep, infected cattle did have a shift (decrease, approximately 0.8) in the peripheral CD4/CD8 ratio associated with an increase in circulating BoT8 (CD8)+ lymphocytes on day 14 post infection. Lymphocytes in the peripheral blood of all sheep and cattle infected with BTV-17 proliferated in vitro in response to purified BTV-17. These results confirm and extend those of previous studies that indicate species differences in the hematologic response to an equivalent BTV infection in domestic ruminants.     

Immunity of specific pathogen-free lambs to challenge with an aerosol of Pasteurella haemolytica biotype A serotype 2. Pulmonary antibody and cell responses to primary and secondary infections

Specific pathogen-free (SPF) lambs previously exposed to an aerosol of P. haemolytica biotype A serotype 2 (A2) were immune to subsequent challenge with an aerosol of P. haemolytica A2. Untreated control lambs were not immune to this challenge. The local immune responses of the lung to these challenges were examined. High IgG and IgA titres to P. haemolytica and high levels of opsonizing antibody against P. haemolytica were present in the lung washings from previously infected immune lambs at autopsy, seven days after the second infection. Lung washings from control lambs, 7 days after challenge with P13 virus and P. haemolytica A2, had no IgG titres, very little opsonizing activity but did have IgA titres which were significantly higher than in unchallenged control lambs. The cellular response of animals challenged with P13 virus and P. haemolytica was significantly greater than that of unchallenged controls or of lambs exposed only to P. haemolytica. However, this finding was complicated by the response to P13 virus. Lymphocytes from lung washings of all lambs failed to respond in a lymphocyte stimulation test to phytohaemagglutinin while blood lymphocytes did respond. There was little specific response to P. haemolytica antigen in the test.     

The effect of parainfluenza virus type 3 and Pasteurella haemolytica on oxygen-dependent and oxygen-independent bactericidal mechanisms of ovine pulmonary phagocytic cells

Groups of caesarean-derived, colostrum-deprived lambs were inoculated by the intratracheal route with Pasteurella haemolytica, either alone or 4 or 6 days after the inoculation of parainfluenza virus type 3 (PI3). Other groups were inoculated with PI3 followed by veal infusion broth, or with uninfected cell culture fluid followed by veal infusion broth (controls). All lambs were killed 24 h after the second inoculation. Pulmonary phagocytic cells were recovered by lavage and separated into alveolar macrophage (AM) and neutrophil fractions by density gradient centrifugation. Bacterial proliferation was detected in the lungs of all five lambs inoculated with P. haemolytica 6 days after PI3 but in only one of five inoculated with P. haemolytica 4 days after PI3 and one of five inoculated with P. haemolytica alone. The number of phagocytic cells recovered from the lungs was highest in animals inoculated with P. haemolytica 6 days after PI3 and, overall, a greater number of both AM and neutrophils was recovered from the lungs of animals where bacterial proliferation occurred (greater than 10(5.0) P. haemolytica 100 g-1 lung) than from those that controlled the bacterial infection. Oxygen-dependent bactericidal activity of AM and neutrophils was measured by chemiluminescence. Infection with PI3 and P. haemolytica increased the chemiluminescence responses. The highest responses were recorded from lambs inoculated with P. haemolytica 6 days after PI3, the group where pulmonary clearance was poorest. Overall, responses were higher in lambs in which bacterial proliferation occurred than in those that controlled the infection. On the other hand, oxygen-independent bactericidal activity, measured by the direct effects of neutrophil lysates on Escherichia coli, was lowest in lambs inoculated with P. haemolytica 6 days after PI3 and was lower in lambs where bacterial proliferation occurred.     

Primary and anamnestic responses of bovine bronchoalveolar and peripheral blood lymphocyte subsets to aerosolized Pasteurella haemolytica A1

Site-specific responses of bronchoalveolar and peripheral blood lymphocyte subsets were compared during primary and anamnestic immune responses against live Pasteurella haemolytica A1 (Ph1). Eight 1-year old calves were sequentially exposed intrabronchially with aerosolized Ph1 on days 0, 14, and 21, and two calves were sham exposed. Bronchoalveolar and peripheral blood lymphocytes were analyzed before each Ph1 exposure, and on days 3 and 7 post exposure using single and two-color flow cytometry to identify CD2+, CD4+, CD8+, CD21+, CD45R+, CD25+ and gammadelta lymphocyte subsets. Significant differences (p < 0.05) in bronchoalveolar and peripheral blood lymphocyte subsets were observed before Ph1 exposure. Subsequent aerosol exposures, resulted in significant (p < 0.05) changes in bronchoalveolar lymphocyte subsets and the CD4:CD8 bronchoalveolar lymphocyte ratio, but concomitant changes were not observed in peripheral blood lymphocytes. Expression of CD2, CD4 and CD8 lymphocyte differentiation antigens was consistently lower and more heterogeneous on bronchoalveolar lymphocytes. Differential analysis of bronchoalveolar leukocytes revealed a significant increase in bronchoalveolar lymphocytes and neutrophils during anamnestic responses.     

Characterisation of lesional infiltrates of dendritic cells and T cell subtypes during primary infestation of sheep with Psoroptes ovis, the sheep scab mite

Earlier studies of cattle and sheep have demonstrated that Psoroptes ovis infestations provoke an intense immunoinflammatory response dominated by eosinophils accompanied by a substantial infiltrate of lymphocytes. However, the kinetics of the lymphocyte response and the subtypes involved have not been characterised. We employed two groups of sheep to investigate the early (1-21 days) and later (21-63 days) infiltration of lymphocyte subpopulations and dendritic cells in primary infestations of sheep with P. ovis. Immunohistochemistry indicated that by 4 days after infestation numbers of CD4+ and CD45RA+ cells in lesional skin had increased significantly (P<0.03 and P<0.005, respectively) and that a significant increase in gammadelta T cells and dendritic cells (CD1b+) had occurred by 8 days (P<0.02 and P<0.01, respectively). Numbers of lymphocyte and dendritic cells declined from 49 to 63 days after infestation. Our observations suggest that mite-derived products exert a profound influence on the early recruitment of lymphocytes that may significantly influence the genesis of the adaptive immune response.     

Interaction of bovine respiratory syncytial virus and Pasteurella haemolytica in the ovine lung

The potential synergistic effect of bovine respiratory syncytial virus (RSV) and Pasteurella haemolytica in the production of pneumonia after aerosol/intranasal infection of conventionally reared lambs was evaluated. A mild clinical response was observed in lambs given virus and/or bacteria. Gross pulmonary lesions were seen in 3 of 6 lambs given RSV and then P haemolytica 3 or 6 days later, respectively (groups D and E), and in 1 lamb of 5 given virus and bacteria simultaneously (group G). Gross lesions were not seen in control sheep (group A), in lambs given virus or bacteria alone (groups B and C), or in lambs exposed to bacteria and then virus 3 days later (group F). Bovine RSV and P haemolytica were recovered from the lungs of 5 of 7 lambs with macroscopic lesions. Gross pulmonary lesions were cranioventral firm areas of red consolidation. Microscopically, the predominant lesion was a suppurative bronchopneumonia. Bovine RSV was recovered from the nasal cavity of 8 of 27 (30%) lambs given RSV during days 3 to 6 after viral inoculation, including 1 lamb in group B, 2 in groups D, E, and F, and 1 in group G. Pasteurella haemolytica was recovered from the nasal cavity of 9 of 28 (32%) inoculated lambs, including 2 lambs from groups C and E, 3 in group D, and 1 in groups F and G. Viral antigen, as determined by immunofluorescence, was concentrated mainly in individual cells in alveolar walls, some alveolar macrophages, and a few bronchiolar epithelial cells. In vitro alveolar macrophage assays indicated decreased numbers of Fc receptors on those macrophages collected from lambs given RSV 6 days before P haemolytica infection, as compared with that in the other groups. These cellular defects disappeared after 24 hours of culture. Seemingly, bovine RSV does facilitate P haemolytica pulmonary infection in conventional, immuno-competent lambs and provides evidence for decreased Fc receptors on alveolar macrophages.     

The effect of parainfluenza virus type 3 on the phagocytic cell response of the ovine lung to Pasteurella haemolytica

Groups of Caesarean-derived, colostrum-deprived lambs were inoculated by the intratracheal route with Pasteurella haemolytica 4 to 6 days after the inoculation of parainfluenza virus type 3 (PI3). Some were killed immediately (0 h) and others 24 h later. Control groups were inoculated with PI3 alone, P. haemolytica alone or media alone. Pulmonary phagocytic cells, P. haemolytica and PI3 were recovered by pulmonary lavage. The phagocytes were separated into alveolar macrophage (AM) and neutrophil fractions by density gradient centrifugation and examined biochemically and microbiologically. Twenty-four hours after the inoculation of P. haemolytica bacterial proliferation to greater than 0 h levels had occurred in four of six animals inoculated with P. haemolytica alone, two of eight inoculated with P. haemolytica 4 days after PI3 and all of eight inoculated with P. haemolytica 6 days after PI3. Mean bacterial numbers in animals inoculated with P. haemolytica 6 days after PI3 and killed at 24 h (10(9.1 +/- 1.9)) were significantly higher than they were in the other two groups killed at this time (PI3 4 days, P. haemolytica 24 h, mean = 10(5.3 +/- 1.7); P. haemolytica alone 24 h, mean = 10(4.5 +/- 2.9)). Pneumonic lesions were also more severe in the first group. This defect in pulmonary clearance and increase in the severity of pneumonia in animals inoculated with P. haemolytica 6 days after PI3 coincided with a 1000-fold decrease in virus titres in the lung between Day 6 and Day 7 after virus inoculation and the first detectable evidence of the host's immune response. The virus infection resulted in a significant increase in the number of AM that could be recovered from the lung and an increase in the number of AM with cytoplasmic vacuolation. However, there was no difference in the total number of AM or the number of vacuolated AM between animals that controlled the P. haemolytica infection and those in which proliferation of P. haemolytica occurred. The inoculation of P. haemolytica resulted in a 100-fold increase in the number of neutrophils in the lavage fluid, but there were no differences between virus-infected and uninfected animals, nor was there a difference between animals that controlled the P. haemolytica infection and those that did not.(ABSTRACT TRUNCATED AT 400 WORDS)     

Analysis of ovine peripheral blood lymphocyte subsets following Ficoll-Hypaque separation or erythrocyte lysis

Peripheral blood lymphocyte subsets were analysed with the aid of monoclonal antibodies and flow microfluorometry following separation by either the Ficoll-Hypaque method or erythrocyte lysis of the buffy coat. The percentage of lymphocytes labelled by the monoclonal antibodies SBU-T1, SBU-T4 and SBU-T8 were significantly greater (P less than 0.05) in samples obtained by erythrocyte lysis. In contrast, a lower percentage of lymphocytes was labelled by SBU-T6 following erythrocyte lysis (P less than 0.02). These data suggest caution when choosing a method for separation of peripheral blood lymphocytes.     

基因枪与肌肉注射猪繁殖与呼吸综合征病毒ORF5基因疫苗诱导小鼠体液及细胞免疫的比较研究

猪繁殖与呼吸综合征病毒ORF5基因疫苗（pcDNA—PRRSV—ORF5）以不同免疫途径（基因枪和肌肉注射）免疫BALB／c小鼠，以PBS和空载质粒pcDNA3．1（＋）为对照，采用流式细胞仪（FACS）、淋巴细胞增殖试验（MTT法）及间接ELISA试验分别对小鼠外周血中CD4^＋、CD8^＋T淋巴细胞数、T淋巴细胞的转化功能及小鼠血清中特异性PRRSV血清抗体IgG动态变化进行了检测。结果表明，pcDNA—PRRSV-ORF5基因疫苗接种小鼠后外周血对ConA有明显的反应性，试验组与对照组比较差异极显著（P〈0．01）或显著（P〈0．05），CD4^＋T淋巴细胞数在免疫后7d高于对照组（P〈0．01），CD8^＋T淋巴细胞在免疫后28d高于对照组，不同途径基因疫苗接种小鼠后均诱导小鼠产生PRRSV特异性IgG。在诱导细胞免疫方面，基因枪和肌肉注射各组间无明显差异；在诱导体液免疫方面，基因枪法优于肌肉注射。研究表明制备的pcDNA—PRRSV—ORF5基因疫苗免疫小鼠能够诱导其机体产生良好的体液和细胞免疫应答，基因枪法较肌肉注射更能诱导体液免疫应答的产生。     

The effects of florfenicol on lymphocyte subsets and humoral immune response in mice

Florfenicol is a broad-spectrum bacteriostatic antibiotic used in domestic animals. The aim of the study was to determine the effect of florfenicol on the total number of lymphocytes in the thymus, spleen and mesenteric lymph nodes and the percentage and the absolute number of T cell subsets (CD4+CD8+, CD4-CD8-, CD4+, CD8+) in the thymus and T (CD3+, CD4+, CD8+) and B (CD19+) lymphocytes in the peripheral lymphatic organs in non-immunized mice and humoral immune response in sheep red blood cells (SRBC)-immunized mice. Florfenicol was administered orally at a dose of 30 mg/kg six times at 24 h intervals to non-immunized mice and four or seven times at 24 h intervals to SRBC-immunized mice. SRBC was injected 2 hours prior to the first dose of the drug. Florfenicol increased the percentage of CD4CD8- thymocytes and the absolute number of CD4+ and CD8+ thymocytes on day 7. The increased percentage and absolute number of CD3+, CD4+ and CD8+ lymphocytes in mesenteric lymph nodes and decreased percentage of lymphocytes B were also observed 24 hours from the last administration of florfenicol. Florfenicol administered after SRBC immunization reduced the number of plaque forming cells (PFC) and the production of anti-SRBC antibodies on days 4 and 7 after priming.     

Effect of CD4+ T lymphocyte depletion on resistance of Gulf Coast Native lambs to Haemonchus contortus infection

It has been reported that CD4(+) T lymphocytes are important in acquired immunity to gastrointestinal nematode infection. Whether these lymphocytes are also involved in the immune response of naturally resistant Gulf Coast Native (GCN) sheep to Haemonchus contortus infection remains to be defined. The objective of this study was to determine the role of CD4(+) T lymphocytes in this resistance. Ten GCN lambs were randomly assigned to a control (n=5) or a treatment (n=5) group. The treatment consisted of a series of IV injections with mouse anti-ovine CD4(+) T lymphocyte monoclonal antibodies for a period of 3 weeks. After the second treatment, all lambs were experimentally infected with 10,000 H. contortus infective larvae by oral inoculation. All lambs were monitored for fecal egg counts, blood packed cell volumes, white blood cell differential counts and serum antibody responses on a weekly basis. Fluorescence-activated cell sorter (FACS) analysis was done biweekly to enumerate CD4(+) T lymphocytes in peripheral blood. Necropsies were performed at the end of the study and 10% of the contents of the gastrointestinal tract were preserved for nematode enumeration and identification. Also at necropsy, mesenteric lymph nodes were extracted and FACS analysis was run on lymphoid cells. Mean fecal egg counts on day 21 and 28 post-infection and nematode counts at necropsy of the treated group were significantly (p<0.05) higher than that of the control group. Percent CD4(+) T lymphocytes in peripheral blood was significantly (p<0.05) lower in the treatment group than in the control group from day 9 to the end of the study. No differences were found in blood packed cell volumes, white blood cell differential counts, antibody titer or lymph node CD4(+) lymphocytes between groups. Lambs depleted of their CD4(+) T lymphocytes were more susceptible to H. contortus infection than undepleted lambs. The results of this study suggest that CD4(+) T lymphocytes are associated with the natural resistance of GCN sheep to H. contortus infection.     

Characterisation of immunosuppression in rabbits after infection with myxoma virus

Myxoma virus (MXV) causes the systemic disease myxomatosis in the European rabbit. Despite many in vitro studies on the function of MXV immunomodulatory proteins and detailed molecular knowledge of virus, little is known about the dynamics of interaction of the virus with the integrated host-immune system during infection. In this study changes in haematological profile, changes in lymphocyte subset distribution and non-specific proliferation activity of lymphocytes from different lymphoid compartments on the 2nd, 4th, 6th, 9th and 11th day after experimental infection of rabbits with MXV strain Lausanne was characterised. The relationship between alterations of immune parameters and dynamic of virus dissemination through the body was investigated. Haematological changes included moderate leucopenia with significant lymphopenia, neutrophilia, monocytosis and eosinopenia. A decrease of T cells including CD4+ and CD8+ and increase of CD79alpha+ were observed in draining popliteal lymph node 4 days after virus inoculation. From day 6, comparable changes were seen in collateral popliteal lymph node, spleen and peripheral blood. From day 9, the mentioned lymphocyte subsets tended to reach their original state in all of these lymphocyte compartments except draining popliteal lymph node. In thymus, MXV infection affected mainly CD4+CD8+ double positive thymocytes. On the other hand, proliferation activity of lymphocytes determined by the proliferation assay with plant-derived mitogens was significantly reduced from day 4 or 6 and remained reduced until the end of experiment in all observed lymphoid organs. Presence of MXV in respective lymphoid compartments preceded changes in lymphocyte subset distribution or lymphocyte activity.     

E.tenella初次感染雏鸡外周血T淋巴细胞亚群及增殖能力变化的动态研究

应用流式细胞术（ FCM）和MTS比色法检测雏鸡初次感染柔嫩艾美尔球虫（ E． tenella）后外周血中CD3＋CD4＋、CD3＋CD8＋T淋巴细胞及其增殖能力的动态变化。数据显示,E． tenella初次感染雏鸡后7～20 d CD3＋CD4＋、CD3＋CD8＋T 淋巴细胞比例明显高于对照组雏鸡（ P＜0．05和P＜0．01）,并且均于12 d时达到峰值。初次感染后7～20 d雏鸡外周血中CD4＋／CD8＋T淋巴细胞亚群的比值明显升高,于感染后16 d时达到1．78。 E． tenella初次感染雏鸡后12～20 d外周血淋巴细胞增殖能力明显高于对照组雏鸡（ P＜0．05）,并于16 d达到峰值。试验表明E． tenella初次感染雏鸡能激活淋巴细胞产生增殖反应,CD3＋CD4＋、CD3＋CD8＋T淋巴细胞在抵抗E． tenella初次感染过程中有重要作用。     

Histologic characteristics and local cellular immunity of the gland of the third eyelid after topical ophthalmic administration of 2% cyclosporine for treatment of dogs with keratoconjunctivitis sicca

OBJECTIVE: To evaluate the efficacy of topical administration of a 2% solution of cyclosporine (CsA) for treatment of dogs with keratoconjunctivitis sicca (KCS) and to correlate results with histopathologic characteristics and local cellular immunity of the gland of the third eyelid. ANIMALS: 24 dogs with bilateral KCS. PROCEDURE: Lacrimal secretion was measured, using Schirmer tear test (STT) strips. Leukocyte and T-lymphocyte subsets were determined in blood samples. Histopathologic changes as well as CD4+, CD8+, and alpha-naphthyl-acetate esterase-positive (ANAE+) lymphocytes were evaluated. RESULTS: Clinical signs resolved at the end of 1 month in conjunction with significantly increased STT values, compared with baseline values. Fifteen and 30 days after discontinuation of CsA treatment, a decrease was observed in STT values in both eyes; however, only values for the right eye were significantly different. There was a significant decrease in the number of lymphocytes and ANAE+ lymphocytes 15 and 30 days after discontinuation of CsA treatment, compared with baseline values. Differences were not observed in number of CD4+ lymphocytes among treatment groups. However, there was a significant decrease in number of CD8+ lymphocytes with reversal of the CD4+:CD8+ in both eyes after CsA treatment for 30 days, compared with the control group. Increased secretory activity and decreased lymphocyte infiltration were characteristic histopathologic findings. CONCLUSIONS AND CLINICAL RELEVANCE: Topical administration of a 2% solution of CsA was effective for the treatment of dogs with KCS. Strict follow-up monitoring is required after the cessation of treatment because of the possibility of recurrence of KCS.     

Changes in peripheral blood leucocyte counts and subpopulations after experimental infection with BVDV and/or Mannheimia haemolytica

Leucocyte counts and subpopulations were studied in peripheral blood from calves experimentally infected in the respiratory tract with either bovine virus diarrhoea virus (BVDV) or Mannheimia haemolytica (Mh), or with a combination of both agents (BVDV/Mh). A non-inoculated control group was included. Peripheral blood samples were obtained for total leucocyte counts, and for neutrophil, lymphocyte and monocyte counts. The numbers of blood lymphocytes expressing the surface antigens CD4, CD8, WC1, B and IL-2R were analysed using flow cytometry. The results showed that BVDV inoculation induced a significant decrease in total leucocyte counts and in neutrophil and lymphocyte numbers, while Mh inoculation induced significant increases in total leucocyte counts and neutrophils, while the lymphocyte count decreased. In the BVDV/Mh group, the total leucocyte count and the lymphocyte numbers decreased significantly. In this group, the lymphocyte numbers remained on a very low level throughout the rest of the study. The numbers of CD4+, CD8+ and WC1+ lymphocytes decreased significantly compared with before inoculations mainly in the BVDV and BVDV/Mh groups. The drops were most pronounced in the BVDV/Mh group. The numbers of B+ lymphocytes and IL-2R+ cells did not change significantly.     

Changes in peripheral blood leukocyte populations in pigs with naturally occurring exudative epidermitis

The objective of the study was to analyze changes in peripheral blood leukocyte subsets in cases of naturally occurring exudative epidermitis (EE) in pigs. Five of ten piglets developed the chronic clinical form of EE 2-5 days after weaning (PW). Blood samples were obtained at 7, 14 and 21 days from both normal and clinically affected piglets for routine haematology and for the determination of CD45, CD21, CD4, CD8 and gammadeltaTCR cell markers by flow cytometry. When compared with clinically normal piglets EE affected pigs showed significantly decreased values of monocytes at 14 and 21 days PW, and increased numbers of neutrophils and leukocytes at 21 days PW. The EE affected pigs also had an early significant CD4(+) and CD8(high+) T lymphocyte proliferative response at 7 days PW. However affected pigs had a significantly reduced number of B (CD21(+)) and gammadeltaTCR(+) T lymphocytes in blood at 21 days PW. Although all values remained within the normal range, the significant differences in some peripheral blood leukocyte subsets between the two groups of piglets suggest that the generalised cutaneous infection with Staphylococcus hyicus is severe enough to induce a systemic inflammatory and immune responses.