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The immune response of sheep infected with larvae of the sheep blowfly Lucilia cuprina monitored via efferent lymph.

Changes in lymphocyte traffic in efferent lymph from the prescapular lymph node of sheep were monitored during local primary and secondary infection with blowfly, Lucilia cuprina. During primary infections the response was characterised by an increase in the output of CD4+ T cells over CD8+ T cells for the first 48 h after wound initiation. By 72 h the output of CD8+ T cells exceeded that of CD4+ T cells. During secondary infections the increased output of CD8+ T cells was more pronounced and occurred earlier at approximately 48 h. The percentage of B lymphocytes as measured by sIg, CD45R and MHC class II expression increased at approximately 96-120 h after both primary and secondary infections, with the secondary response being greater than the primary. This increase in B cells corresponded with peak antibody titres recorded in the efferent lymph to a first instar antigen preparation as measured by ELISA. An increase in IFN-gamma and soluble IL-2 receptor was recorded after both primary and secondary infections, with the response after secondary infection being greater than that recorded after primary larval infections.

Animals↗

Evidence for the role of the sheep biting-louse Bovicola ovis in producing cockle, a sheep pelt defect.

The prevalence and severity of cockle, a sheep pelt defect characterised by raised lumps, was assessed on lambs that were either louse-infested (Bovicola ovis) or louse-free at birth. Assessments were made on pickled pelts, 10 months after the lambs had entered the trial. Lambs kept free of lice did not develop cockle, whereas the defect was common in lambs (about 90%) that were infested with lice. There was a direct correlation between louse scores and cockle, high louse scores being associated with a more severe degree of cockle. The results give support to the strong causal relationship between B. ovis and cockle, but questions such as the minimum number of lice needed to cause cockle and the time required for cockle to develop still need to be answered.

Animals↗

A small scale survey of ivermectin resistance in sheep nematodes using the faecal egg count reduction test on samples collected from Scottish sheep.

Thirty-eight sheep flocks, predominantly from the south/central Scotland, were examined using a faecal egg count reduction test (FECRT) for the presence of ivermectin (IVM) resistant nematodes. Efficacies of less than 95%, 14-17 days post-treatment, were identified in 6 of 17 naturally grazing flocks where pre-treatment faecal egg counts were in excess of 150 eggs per gram. Efficacies on these IVM resistant farms ranged from 66 to 92%. One other suspected cases of IVM resistance was also identified in returned material. The larvae detected in post-treatment coprocultures from resistant flocks were from the genera Teladorsagia (4 from 6) and Trichostrongylus (2 from 6).

Animals↗

Temporal pattern of isotype-specific antibody responses in primary and challenge infestations of sheep with Psoroptes ovis--the sheep scab mite.

In sheep Psoroptes ovis provokes an allergic dermatitis with significant P. ovis antigen-specific IgE responses. The kinetics of the IgE response to primary and challenge infestations of P. ovis were reported earlier [Parasite Immunol. 22 (2000) 407]. The present study examines IgG, IgM and IgA responses to primary and challenge infestations of P. ovis and the profile of antigens/allergens reacting with IgG and IgE antibodies. Antigen-specific enzyme-linked immunosorbent assays (ELISAs) demonstrate that primary infestations elicited significant increases in levels of IgG and IgM but not IgA antibodies. IgG and IgM responses to primary and challenge infestations were not significantly different. Western blots of reduced P. ovis proteins indicate that IgG antibodies reacted with five major antigens following primary infestation and only three of these after challenge infestation. IgE antibodies bound to three major and five minor allergens after primary infestation and two additional minor allergens after challenge infestation. Immunodominant antigens >100 and <15 kDa and allergens >100 kDa were most consistent in stimulating substantial IgG and IgE antibody responses, respectively. These antigens/allergens may be exploited in immunodiagnosis and modulation of the host immune response.

Allergens↗

Cutaneous and systemic responses during primary and challenge infestations of sheep with the sheep scab mite, Psoroptes ovis.

Lesional area was estimated and lesional mast cells and eosinophils were counted during primary and challenge infestations of sheep with Psoroptes ovis. In addition, circulating basophils and eosinophils and serum P. ovis-specific immunoglobulin IgE antibody were quantified. Expansion of lesional area was significantly less and serum IgE titres significantly greater in challenge than primary infestations. Lesional mast cell hyperplasia and massive eosinophil infiltration accompanied by raised titres of P. ovis antigen-specific IgE antibody were compatible with an IgE-mediated Type-1 allergic reaction, while detection of lesional basophils was suggestive of cutaneous basophil hypersensitivity. The temporal pattern of lesional mastocytosis and eosinophil infiltration and the role of these cells and serum IgE in the immune response is discussed.

Animals↗

The prevalence of Sarcocytis spp in dogs, foxes and sheep and Toxoplasma gondii in sheep and the use of the indirect haemagglutination reaction in serodiagnosis.

Sporocysts of Sarcocystis spp were found in the faeces of 39.3 per cent and 25 per cent of farm dogs and foxes respectively. The indirect haemagglutination serodiagnostic test suggested that nearly all sheep in the area sampled became infected early in life and diagnosis of infection by this means correlates well with trichinoscopy findings. The sarcocystis antigens used in serodiagnostic tests did not cross react with sera positive for Toxoplasma gondii. Sarcocystis antigens derived from cattle cross reacted with ovine sera but comparative tests showed the titres to be less than where the homologous antigen was used.

Animals↗

[The kinetics of specific serum antibodies in sheep infested with sheep bot larvae].

The kinetics of specific antibodies of the blood serum of sheep experimentally infested with 80, 160 and 1000 specimens of Oestrus ovis larvae was examined. The affinity pure serum IgG and the immunoferment analysis (ELISA) were used for qualitative estimation of specific antibodies. It has been shown that the level of specific antibodies correlates with the larval biomass and is connected with ontogenesis of this parasite. The younger animals, which were infested for the first time, are characterized by more intensive production of specific IgG than adult reinfested ones. The ways of immunity response formation in animals infested with Oestrus ovis larvae are considered.

Animals↗

Pepsinogen types in worm-free sheep and in sheep infected with Ostertagia circumcincta and Haemonchus contortus.

Pepsinogen isolated from the plasma of Dorset wethers with abomasal burdens of Ostertagia circumcincta was found to have the same proportions of three zymogen subtypes as that isolated from the plasma of Merino wethers with abomasal burdens of Haemonchus contortus. It appears that the underlying pathophysiological response which causes increased plasma pepsinogen concentrations during abomasal parasitism may be the same irrespective of the breed of sheep or species of parasite.

Abomasum↗

Study of gastro-intestinal stronglyosis in a sheep flock on permanent pasture. 1. Sheep parasitism in 1977.

An epidemiological study aimed at defining gastro-intestinal parasitism in sheep qualitatively and quantitatively was carried out in the Limousin area in France. Five lambs were sacrificed regularly every 4 weeks from May till January of the following year. Complete parasite counts were performed on these animals as well as measurements of the plasma level of pepsinogen. In order to define the influence of parasitism on the growth of the animals, the weight gains of lambs treated regularly and untreated lambs were compared. The results of post-mortem examination show that parasitism is mainly linked to the incidence of strongyles. Other observations in the flock have shown that Moniezosis may also play a non-negligeable part. The parasitic level, already high after one month at pasture, reached its maximum in July-August 1977 and was marked by a very high level of parasitism. Among these species found, two played an essential part: Ostertagia circumcincta and Haemonchus contortus. A study of the growth of the lambs showed that within 6 months, the weight gain of the treated animals was twice that of the untreated animals. The effects of parasitism were worsened by the low fodder value of the pasture and the occurrence of overgrazing. The blood pepsinogen measurements confirmed the usefulness of this technique in establishing the mean level of infestation of a flock by parasites of the abomasum. It seems that in some cases it could help to define the succession of peaks of infestation by different species.

Animal Nutritional Physiological Phenomena↗

[Clinical kidney function studies in sheep. III. Pathologic function changes in nephropathies of sheep and in urolithiasis of rams and billy goats].

Examination of renal function have been carried out in sheep with acute prerenal (n = 6), renal (n = 15) or postrenal failure (n = 3), pyelocystitis (n = 4), and in cases of urolithiasis in rams (n = 16) and billy goats (n = 11) respectively. The calculation of parameters was done on the basis of the estimated weight dependent endogenous creatinine excretion. A control group of 56 healthy non pregnant or early pregnant (< 120th day of pregnancy) ewes have been used. The renal creatinine clearance was reduced and the absolute as well as the fractional renal water excretion was enhanced in all groups of sick animals. An elevated fractional excretion of sodium and phosphate could be seen as well. Functional disturbances could be observed in urolithiasis in like manner as in acute renal failure. There was proteinuria, glucosuria, excessive potassium excretion and often decreased plasma concentration of potassium in both syndromes. A hyperkalemia occurred only in the final state of urolithiasis. No clinical outcome of chronic nephropathies could be seen. Mortality of the described acute nephropathies was about 76%. The results of examination were suitable to control the course and restitution of renal function. They were not helpful for differential diagnosis and prognosis of acute renal failure.

Animals↗

[Helminth infection of slaughtered sheep in Upper Bavaria. 3. Distribution of colonization of nematodes in the large intestine of sheep].

The distribution of Chabertia (Ch.) ovina, Oesophagostomum (O.) venulosum and Trichuris spp. within the large intestine of naturally infected sheep in the dependence of worm counts and the presence of nematodes of other species or genera was evaluated. The large intestine was divided into 4 sections. More than 75% of Ch. ovina were found within the disk-like section of the colon independently from worm count and presence of nematodes of other species. O. venulosum and Trichuris spp. preferred the caecum and the first section of the colon up to the beginning of the disk-like section. In both, the share of worms recovered from the first section of the colon did increase with higher worm counts. The simultaneous presence of O. venulosum and Trichuris spp. had a significantly negative influence on the share of Trichuris spp. isolated from the caecum.

Abattoirs↗

The occurrence of paranuclear vacuoles in sheep ruminal epithelium treated with distilled water in vitro and from sheep injected with a large quantity of water into the rumen.

In the histological preparation taken after animal death, paranuclear vacuoles (PV) in sheep ruminal epithelium were already present in high percentage (7.5-20.3%). With the incubation of the ruminal mucosae in distilled water (10-15 degrees C) up to 120 min, PV occurrence did not alter. With incubation in NaCl solution, however, PV value decreased with time proportional to NaCl concentration (0.5, 0.85 or 1.5%). In the preparation taken by biopsy, on the other hand, PV were rare in ruminal epithelium (less than 0.3%). With the injection of warm water (10-141/animal), however, PV occurrence in the ruminal epithelium was not affected. PV as cytoplasmic processes of the ruminal Langerhans cells are probably formed by the reaction of these cells to environmental changes in the tissue caused by animal death.

Animals↗

A human B-cell line (BES-1) forming rosettes with sheep erythrocytes, producing Forssman antibody, and phagocytizing sheep erythrocytes.

A lymphoid cell line, designated BES-1, belonging to "lymphoblastoid cell lines with B-cell properties (B-LCL)" and derived from some normal B lymphocytes, was established in an attempt at primary culture of peripheral blood from a patient with acute myelogenous leukemia (AML). BES-1 cells unexpectedly formed rosettes with sheep erythrocytes (SRBC), which are usually a T-cell marker, and phagocytized SRBC. Subsequent study indicated that BES-1 cells produce antibody specific to Forssman (F) antigen, but not to Paul-Bunnell (P-B) or Hanganutzin-Deicher (H-D) antigen.

Adult↗

Factors affecting the voluntary intake of food by sheep. 4. The effect of additives representing the primary tastes on sham intakes by oesophageal-fistulated sheep.

1. Sheep with oesophageal fistulas were sham-fed on pelleted lucerne (Medicago sativa) hay to assess the palatability of added chemicals representing the tastes of sweet (sucrose), sour (hydrochloric acid), salt (sodium chloride), bitter (urea) and umami (monosodium glutamate; MSG). 2. Plain pellets and four concentrations of each chemical were sham-fed for 30 min after 5.5 h deprivation in 5 x 5 Latin-square experiments following a period of adaptation feeding. 3. Sucrose, at concentrations of 15-120 g/kg air-dried pellets, depressed intakes with a linear relation between intake (I; g) and concentration (C; g/kg): I = 1001-3.42C. 4. HCl at 6.25-25.0 g/kg pellets had no effect on sham intakes but at 50 g/kg reduced them by 50% of control (P less than 0.05). 5. NaCl at 50 200 g/kg increased sham intakes by 26% (P less than 0.01) with no evidence of a dose-related effect. 6. Urea at 10-80 g/kg decreased sham intakes by 26.9% (P less than 0.01) with no evidence of a dose-related effect. 7. MSG at 5-40 g/kg in two experiments increased sham intakes by 16.1 and 40.8% (P less than 0.05). In another experiment at 1-8 g/kg there was no significant effect. 8. When palatability and post-ingestive effects are separated by sham-feeding, the effect of added chemicals on intake may be completely different from when they are ingested normally (e.g. NaCl and sucrose). This newly developed technique enables the palatability effect of feed additives to be tested critically and economically.

Animal Feed↗

[Consumption and ruminating behavior in sheep. 5. Continuous registration and recording of consumption and rumination dependent jaw movements in sheep based on acceleration measurements].

A method of the registration of the feed intake and ruminating behaviour of sheep which uses piezoelectric converters was tested. The appliance-technological solution and the feasibility and routine measurings are described. It showed that measurings on the basis of acceleration registration produced similar results as the 'halter method with plate feelers' used so far and that disturbance of the test animals is reduced.

Animal Feed↗

Effect of the progesterone-induced serpin-like proteins of the sheep endometrium on natural-killer cell activity in sheep and mice.

Natural killer (NK)-like cells have been implicated as an important component of the endometrial lymphoid cell population and have been suggested to play roles in resistance to viral infection, in abortion, and in fetal growth. Inhibition of endometrial NK cell activity may be an important aspect of successful pregnancy because of the potential for actions directed against the conceptus. The aim of the study reported here was to test the hypothesis that the uterine milk proteins (UTM-proteins) inhibit activity of NK cells. Physiological concentrations of enriched preparations of UTM-proteins, which are a pair of related proteins that represent the major lymphocyte-inhibitory molecules in uterine fluid of pregnant and progesterone-treated ewes, were found to inhibit cytotoxic activity of cultured sheep and mouse NK cells. Furthermore, injection of the proteins into mice reduced activity of basal and poly(I).poly(C)-induced NK activity in spleen and prevented a slight increase in fetal loss caused by injection of poly(I).poly(C). These results further implicate the UTM-proteins as important regulators of uterine immune function.

Animals↗

Antibody-coated sheep erythrocytes suppress the ability of polyclonal B-cell activators to induce plaque-forming cells against sheep erythrocytes.

The primary immune response to untreated sheep erythrocytes (SRBC) in vitro was suppressed by the addition of antibody-coated SRBC. A mixture of SRBC and antibody-coated SRBC also suppressed the induction of anti-SRBC plaque-forming cells by the polyclonal B cell activators lipopolysaccharide, purified protein derivative of tuberculin, and native dextran. Injection of a mixture of SRBC and antibody-coated SRBC into mice led to an increased response to SRBC. It seems plausible from the in vitro findings that the Fc part of antibodies complexed to an antigen can exert a negative signal on antigen-specific B cells that cannot be overcome by positive signals delivered by polyclonal B cell activators.

Animals↗

Comparison of the segregation of sheep histocompatibility genes OLA - A1, A8, B7, B9, and OLX-5 in eighteen hamster X sheep fibroblast hybrid lines.

Four OLA factors of the ovine histocompatibility complex and the OLX -5 factor were recognized in hamster cell X sheep fibroblast hybrids, by means of absorption of OLA reagents with hybrid cells. Segregation of these factors could be studied in eighteen independent hybrids. In the case described, the four OLA factors were distributed into two haplotypes isolated in some hybrids. The heterozygous OLX-5 factor was linked to only one haplotype; nevertheless a dissociation, occurred in one hybrid (relative to five simultaneous transmissions), is in agreement with a previous genetic study showing a loose linkage between the OLA complex and the OLX locus.

Animals↗