IL-1α Modulates IFN-γ-Induced Production of CXCL9/MIG during Herpes Simplex Virus Type-1 Corneal Infection.

PURPOSE: Investigating the modulation of neutrophil production of MIG and IP-10 during the inflammatory response to HSV-1 infection. MATERIALS AND METHODS: An ex vivo model of human corneal infection by HSV-1 was used for this study. This model permits the study of cytokine production by human corneal buttons in the presence, or absence, of gradient purified human neutrophils, under conditions of HSV-1 infection. All experimental samples were stimulated with a baseline concentration of recombinant human IFN-γ at 1 ng/mL. The relative levels of production for 12 pro-inflammatory mediators were screened using a multi-analyte ELISA assay. Neutrophil production of chemokines MIG and IP-10, under conditions of IFN-γ and/or HSV-1 stimulation were measured by quantitative ELISA. Lastly, antibody neutralization (goat IgG anti-human IL-1α, 2 µg/mL) of de novo production of IL-1α by corneal tissue was performed to investigated the effect on MIG and IP-10 production in the ex vivo model for HSV-1 infection. RESULTS: Four of the 12 pro-inflammatory mediators screened (IL-8, IL-6, IL-1α and IL-1ß) demonstrated elevated levels of production during corneal cell infection with HSV-1 and communication with neutrophils. Neutrophils were demonstrated to produce significant levels of both MIG and IP-10 under conditions of IFN-γ stimulation, and production of MIG was further upregulated by co-stimulation with IFN-γ and HSV-1. Neutralization of de novo IL-1α production in the model resulted in increased production of the chemokine production MIG but had no observable effect on IP-10 production. CONCLUSIONS: Our data provide evidence demonstrating the potential for expression patterns of MIG and IP-10 to be modulated by IL-1α, during the inflammatory response to HSV-1 corneal infection. Both corneal cells and neutrophils contribute to the production of T cell recruiting chemokines. However, IL-1α has the potential to upregulate MIG production by corneal cells while down-regulating MIG production by neutrophils.

Resident Corneal Cells Communicate with Neutrophils Leading to the Production of IP-10 during the Primary Inflammatory Response to HSV-1 Infection.

In this study we show that murine and human neutrophils are capable of secreting IP-10 in response to communication from the HSV-1 infected cornea and that they do so in a time frame associated with the recruitment of CD8(+) T cells and CXCR3-expressing cells. Cellular markers were used to establish that neutrophil influx corresponded in time to peak IP-10 production, and cellular depletion confirmed neutrophils to be a significant source of IP-10 during HSV-1 corneal infection in mice. A novel ex vivo model for human corneal tissue infection with HSV-1 was used to confirm that cells resident in the cornea are also capable of stimulating neutrophils to secrete IP-10. Our results support the hypothesis that neutrophils play a key role in T-cell recruitment and control of viral replication during HSV-1 corneal infection through the production of the T-cell recruiting chemokine IP-10.

Potential for estimation of body condition scores in dairy cattle from digital images.

Body condition scoring, an indirect measure of the level of subcutaneous fat in dairy cattle, has been widely adopted for research and field assessment or for management purposes on farms. The feasibility of utilizing digital images to determine body condition score (BCS) was assessed for lactating dairy cows at the Scottish Agricultural College Crichton Royal Farm. Two measures of BCS were obtained by using the primary systems utilized in the United Kingdom (UK-BCS) and the United States (USBCS). Means were 2.12 (+/-0.35) and 2.89 (+/-0.40), modes were 2.25 and 2.75, and ranges were 1.0 to 3.5 and 1.5 to 4.5 for the UKBCS (n = 2,346) and USBCS (n = 2,571), respectively. Up to 23 anatomical points were manually identified on images captured automatically as cows passed through a weigh station. Points around the hooks were easier to identify on images than points around pins and the tailhead. All identifiable points were used to define and formulate measures describing the cow's contour. For both BCS systems, hook angle, posterior hook angle, and tailhead depression were significant predictors of BCS. When the full data set testing only the angles around the hooks was used, 100% of predicted BCS were within 0.50 points of actual USBCS and 92.79% were within 0.25 points; and 99.87% of predicted BCS were within 0.50 points of actual UKBCS and 89.95% were within 0.25 points. In a reduced data set considering only observations in which the tailhead depression angle was available, adding the tailhead depression to models did not improve model predictions. The relationships of the calculated angles with USBCS were stronger than those with UKBCS. This research demonstrates the potential for using digital images for assessing BCS. Future efforts should explore ways to automate this process by using a larger number of animals to predict scores accurately for cows across all levels of body condition.

A novel role for neutrophils as a source of T cell-recruiting chemokines IP-10 and Mig during the DTH response to HSV-1 antigen.

Analogous to CD4+ T cells, neutrophils are essential participants in delayed-type hypersensitivity (DTH) to Herpes simplex virus type 1 antigen. However, what role they play in this cellular immune response is unclear. The recent recognition that neutrophils are potent producers of chemokines led us to hypothesize that they may help recruit CD4+ effector T cells. In the present study, we show that neutrophil depletion was accompanied by a marked decrease in the numbers of CD4+ and CXC receptor 3+ (CXCR3+)-expressing cells migrating to the DTH site and a sharp drop in the levels of interferon-inducible protein 10 (IP-10) and monokine induced by IFN-gamma (Mig). Purified mouse neutrophils were stimulated directly by IFN-gamma to secrete these chemokines, and neutrophils at the DTH site expressed IP-10. IFN-gamma knockout mice, which manifested depressed ear-swelling following DTH challenge, made little IP-10 and no Mig. Reconstitution of these mice with IFN-gamma induced CXCR3 ligand synthesis. Depletion of neutrophils or CD4+ T cells but not CD8+ T cells markedly reduced IFN-gamma levels, suggesting the former were direct (or indirect) cellular sources of this cytokine. Collectively, our results support the hypothesis that neutrophil production of T cell-recruiting chemokines contributes to the regulation and amplification of the DTH response.

Emergency management of disasters involving livestock in developing countries.

Different disasters have similar consequence on the health and welfare of livestock. Numerous geophysical disasters can exacerbate epizootics, resulting in the deaths of many animals and the reduction of production efficiency. These disasters also present a considerable threat of spoilage of processed foods, endangering public health. Furthermore, large-scale disasters involving animals can modify the long-term stability of national economies, the environment and social structures. The authors discuss the vulnerability of the livestock industry to natural disasters and the impact of floods, droughts and transboundary diseases and pests on national economies. Examples are given on how some losses can be avoided, evaluated and compensated. The role of the veterinarian is presented in relation to work conducted by other relief organisations in cases of emergency. In developing countries, mitigation programmes should focus on strengthening global animal health services. Preparedness needs to be community based, with education provided in a timely manner. Effective recovery from disasters should be based on mitigation programmes, including international trade and mutual aid agreements between neighbouring countries to supply appropriate goods and environmentally and culturally appropriate breeds of livestock. Disaster relief for the care of livestock should be recognised as a form of humanitarian assistance, given the benefits to be derived for public health and the socio-economic implications of successful intervention.

The effects of restraint using self-locking stanchions on dairy cows in relation to behavior, feed intake, physiological parameters, health, and milk yield.

Holstein cows (n = 64) ranging from peak to end lactation were restrained in self-locking stanchions (i.e., head locks) for approximately 4 h/d for four periods in a modified switchback design. Milk yield, milk fat percentage, somatic cell count, and dry matter intake and dry matter intake were unaffected by restraint. Milk protein percentage was significantly lower for cows that were restrained. Plasma cortisol concentrations and the ratio of neutrophils to mononuclear cells were not significantly different between restrained and unrestrained (control) cows. No difference in the incidence of mastitis or other health concerns was noted. Behaviorally, cows that were locked in the stanchions spent significantly more time lying after release from restraint. For cows that were locked up, eating frequency over 24 h was significantly reduced, but dry matter intake was not affected. Total rumination frequency over 24 h was not significantly different for cows that were restraubed; however, cows that were restrained ruminated less during the day following release. Grooming was considered to be a behavioral need and was significantly increased during all times when cows were not locked up. Grooming was also one of the first behaviors performed following release. Acts of aggression were elevated during all periods following restraint, but oral behaviors, such as tongue playing and chewing on objects, drinking behavior, and resting postures were not affected. The use of self-locking stanchions did not appear to affect substantially the overall well-being of the cow.

Isolation of Brucella abortus from experimentally infected dromedary camels in Sudan: a preliminary report.

Six camels were experimentally infected with two strains of Brucella abortus, four with S19 and two with a field bovine strain. In all cases antibody titres were detected within 6 to 11 days. Serum agglutination titres peaked between days 11 and 32 and complement fixation titres between days 11 and 52; both titres then declined steadily. No clinical signs were observed in the four camels inoculated with S19. Slight non-specific symptoms were seen in the two camels infected with the field bovine strain. On post mortem examination no gross lesions were observed although histopathological sections showed focal granulomata in the liver and a generalized lymphadenitis. The organism was recovered mainly from the lymph nodes of the head and genital tract.

Brucella antibodies in Sudanese camels.

Sera of 740 camels of both sexes from three regions of Sudan were tested for antibodies to Brucella abortus. The overall incidence of antibodies was 4.9%. The highest positive number of samples (7.5%) was from the Eastern Region followed by Darfur Region (3.1%) and the Central Region (2.0%). Brucella antibodies were as frequent in males (5.6%) as females (4.5%).

Effect of total calorific deprivation on host defence in the horse.

Horses were deprived of food but not water for a period of five days. There was a progressive decrease in circulating lymphocyte count and compromised host deference. In vitro phagocytosis of yeast fell from a mean of 97 per cent in fed horses to 78 per cent in horses deprived of food for five days. The Arthus response to intradermal challenge with allergens fell to 57 per cent of fed values. These changes indicated that food deprivation increases the susceptibility to bacterial infections; persistent anorexia in chronic bacterial infections may limit the horse's ability to cast off infection.

Induction of lymphosarcoma in sheep by bovine leukemia virus.

Newborn sheep inoculated with phytohemagglutinin (PHA)-treated short-term, cultures of lymphocytes from cattle infected with bovine leukemia virus (BLV) or with a BLV- infected long-term culture of bovine leukemic lymphocytes became persistently infected with BLV. Fifty percent or more of the sheep died with histologically confirmed lymphosarcomas. Cytogenetic studies of representative cases demonstrated that the tumors did not result from the progressive growth of neoplastic lymphocytes in the inoculum but rather from the neoplastic transformation of the recipients lymphoid cells. Neither BLV infection nor lymphosarcoma was observed in control uninoculated sheep or in sheep given injections of PHA-treated cultures of lymphocytes from BLV-free cows. The virus recovered from the tumorous sheep was indistinguishable from BLV morphologically, antigenically, and biologically, and its reverse transcriptase had the same cation preference and immunologic properties as the BLV enzyme. Persistent BLV infection and lymphosarcoma were also observed in a group of sheep inoculated neonatally with BLV-containing cell-free culture supernatants. These results extend previous observations on the high susceptibility of sheep to BLV infection and provide definitive evidence that BLV is a tumor-inducing virus.

Evidence that the spontaneous blastogenesis of lymphocytes from bovine leukemia virus-infected cattle is viral antigen specific.

Cattle lymphocytes cultured for 3 days were found to spontaneously incorporate thymidine (3STI). Under optimal conditions of culture, the median magnitude of 3STI activity in lymphocytes from bovine leukemia virus (BLV)-infected cattle was higher than that of BLV-free cattle, but the ranges of the values overlapped. However, the 3STI activity of most BLV-infected cattle was specifically inhibited by serum containing BLV antibodies, whereas the 3STI activity of BLV-free cattle was not. The 3STI inhibitor copurified with immunoglobulin, and its activity could be absorbed with BLV. Rabbit anti-BLV serum inhibited 3STI, but rabbit anti-BLV p25 did not. These results indicate that BLV infection induces or expands a BLV-specific lymphocyte population. Spontaneous blastogenesis may be indicative of an immune response which controls virus spread.

Milk of dairy cows frequently contains a leukemogenic virus.

Milk or viable milk cells collected from 24 dairy cattle naturally infected with bovine leukemia virus were inoculated into lambs, which were subsequently examined for the development of infection. With this bioassay, infectious virus was demonstrated in the milk of 17 of the cows. Bovine leukemia virus is leukemogenic in at least two mammalian species, is widespread in commercial dairy herds, and can infect a wide range of hosts in vivo and cells, including human cells, in vitro.

Glucocorticoid effects on peripheral blood lymphocytes in cows infected with bovine leukemia virus.

We examined the effects of glucocorticoids on peripheral blood lymphocytes (PBL) in lymphoproliferative conditions associated with bovine leukemia virus (BLV): persistent lymphocytosis (PL) and lymphosarcoma cell leukemia (BLSL). The effects of hydrocortisone 21-sodium succinate (HSS) on spontaneous incorporation (SI) and mitogen-stimulated incorporation of radiolabeled-thymidine and the effects of intramuscular administration of prednisolone acetate were studied. An expanded population of B lymphocytes in cows with PL was remarkable sensitive to glucocorticoids in vitro and in vivo. SI was markedly inhibited by concentrations of HSS as low as 10(-7) M. These results correlated well with in vivo observations, where an 80%-90% decrease in PBL occurred during the course of glucocorticoid administration. The decrease in total lymphocytes was accounted for almost entirely by a decrease in the expanded B lymphocyte population. Steroid-sensitive lymphocytes together with steroid-resistant cells were observed in cows with BLSL. The reduction in the steroid-sensitive lymphocytes was associated with rapid disease progression in cows with lymphosarcoma. Steroid-sensitive lymphocyte populations in cows with BLSL may include the same reactive B-cell population found in cows with PL. Glucocorticoids may prove to be a useful tool for study of the immune response to the oncogenic virus and lymphoma in BLV-infected cattle.

Persistent lymphocytosis in cattle: its cause, nature and relation to lymphosarcoma.

Studies in well-characterized cattle populations strongly support the view that the bovine leukemia virus (BLV) is the causative agent of the adult (enzootic) form of bovine lymphosarcoma and persistent lymphocytosis (PL), and that host genetic factors play an important role in the development of these two conditions. On the other hand, the available information indicates that the genetic factors controlling the development of PL are frequently independent of those controlling the development of lymphosarcoma. There is no evidence that clinically normal cattle with PL harbor malignant cells or have any other clinical abnormality. In these animals lymphocytosis results from the expansion of two distinct subpopulations of non-neoplastic B lymphocytes, one of which is free of BLV. Long-term studies have shown that the large majority of cattle with PL do not develop lymphosarcoma even when kept to advanced age. These data indicate that PL is not a disease nor a preclinical stage of lymphosarcoma. Rather PL should be considered as a benign response to BLV infection which, although frequently associated with lymphosarcoma, is independant of it.

Cellular basis of persistent lymphocytosis in cattle infected with bovine leukemia virus.

Peripheral blood lymphocytes from 14 cattle infected with the bovine leukemia virus (BLV) and 14 BLV-free cattle were examined by the membrane immunofluorescent antibody technique to detect surface immunoglobulin (S-Ig) and by the erythrocyte-antibody-complement (EAC) rosette test for the detection of complement receptors. Direct comparisons of the percentages of S-Ig-bearing cells and EAC rosette-forming cells in both infected and BLV-free animals showed no evidence for the presence of a substantial population bearing one surface marker but not the other. The data showed that cells with surface markers characteristic of B lymphocytes are responsible for most of the increase in peripheral blood lymphocytes which may accompany BLV infection. The release of infectious BLV and the spontaneous uptake of thymidine by short-term cultured peripheral blood lymphocytes from BLV-infected cattle were also studied. The results indicate that both of these activities are function of B lymphocytes.

Properties of density gradient-fractionated peripheral blood leukocytes from cattle infected with bovine leukemia virus.

Discontinuous bovine serum albumin gradients were used to fractionate peripheral blood leukocytes from bovine leukemia virus (BLV)-free and BLV-infected cows. The release of infectious BLV and spontaneous incorporation of [3H]thymidine were not properties of density gradient-fractionated leukocytes from a BLV-free cow. When leukocytes from BLV-infected cattle were fractionated, B lymphocytes which spontaneously incorporated [3H]thymidine could be separated as a distinct subpopulation from B lymphocytes which replicated infectious BLV. Density gradient fractionation of leukocytes from a cow with lymphosarcoma is also reported. A fall in lymphocyte count at the time of tumor development is attributed to the loss of B lymphocytes which spontaneously incorporate [3H]thymidine.