Gene expression profiling of ovine keratinocytes stimulated with Psoroptes ovis mite antigen--a preliminary study

Sheep scab is caused by the noninvasive mite, Psoroptes ovis, which initiates a profound pro-inflammatory skin response leading to lesion development. To investigate these early events between the skin and the parasite, primary ovine epidermal keratinocyte cultures were generated and challenged with mite derived antigens. The kinetics of the mRNA response of these cells were monitored by microarray. The results indicated that the cells responded within 1 h of challenge, with a significant increase in the pro-inflammatory cytokine IL-8. This result was confirmed by real-time RT-PCR, and showed that IL-8 up-regulation was maximal at 1 h but declined to pre-stimulation levels at 24 and 48 h. The IL-8 mRNA response to mite wash antigens containing secretory and/or excretory proteins was also investigated and compared to the response to whole mite antigen. These studies revealed that the mite wash antigen, at a challenge dose of 10 microg/mL, was markedly more potent and induced significantly higher levels of IL-8 mRNA than the same concentration of whole mite antigen. These results are discussed in relation to mite establishment and survival on the ovine host.

Role of endogenous transplacental transmission in toxoplasmosis in sheep

To investigate the potential role of endogenous transplacental transmission of Toxoplasma gondii, 31 seropositive ewes presumed to be persistently infected with the parasite and 15 seronegative ewes were mated and monitored throughout pregnancy and lambing. Antibody titres were determined in precolostral sera from the liveborn lambs and in thoracic fluid from the dead lambs. A PCR for the B1 gene of T gondii was applied to the placentas from all the ewes and to the brains of the stillborn lambs. Samples of brain, lung, liver, spleen and heart from the dead lambs were examined by histopathology. No evidence of toxoplasmosis was detected by histopathology or PCR in any of the samples, but low titres of antibody to T gondii were detected in two liveborn, healthy offspring of a seropositive ewe by the immunofluorescent antibody test (3.2 per cent of pregnancies and 4.1 per cent of lambs in the seropositive group). Antibody to specific antigens of T gondii was demonstrated in sera from these two lambs by Western blotting.

A house dust mite allergen homologue from poultry red mite Dermanyssus gallinae (De Geer)*

Tropomyosin is an allergenic, actin-binding protein and a proposed vaccine candidate from several species of parasite. Tropomyosin cDNA, obtained by polymerase chain reaction (PCR) amplification from Dermanyssus gallinae RNA, encoded a predicted protein with 89% and 88% identity to tropomyosins from the ticks Boophilus microplus and Haemaphysalis longicornis, respectively, and 85% identity to the house dust mite (HDM) tropomyosin Der p 10. Mouse antibodies raised against HDM tropomyosin reacted with a band of 38 kDa on Western blots of D. gallinae extract, consistent with the molecular masses of acarine tropomyosins and the putative product of the cDNA encoding D. gallinae tropomyosin. When the same preparation of D. gallinae proteins was used in Western blots with serum from infested hens, the IgY component of the serum bound to a number of mite proteins, but not to tropomyosin, indicating that hens are not directly exposed to this allergen during a natural infestation. Immunolocalization of tropomyosin in mites indicated a ubiquitous distribution of the molecule in mite tissues. Immunolocalization and Western blotting also indicated that poultry red mites ingest host IgY.

Cloning and expression of the extra-cellular part of the alpha chain of the equine high-affinity IgE receptor and its use in the detection of IgE

The high-affinity receptor for IgE (FcepsilonRI) plays a central role in IgE-mediated allergic reactions. Cross-linking of FcepsilonRI by IgE-antigen complexes results in the activation of mast cells and basophils and is thought to contribute to the immunopathology of Heaves, a chronic obstructive pulmonary disease of horses. Recombinant protein corresponding to the extra-cellular portion of the FcepsilonRI alpha subunit, cloned and sequenced previously, was expressed using both mammalian cells and insect cells. The yield of expressed protein was considerably greater using insect cells and the baculovirus expression system. The recombinant proteins differed in size between the two systems, presumably due to differences in the extent of glycosylation. However, recombinant protein from both cell systems bound equine IgE present in bronchoalveolar lavage fluid from horses with Heaves. These results suggest that the recombinant extra-cellular part of FcepsilonRI should be a useful tool with which to study equine IgE responses.

Phenotypic and functional characterisation of follicle-associated epithelium of rectal lymphoid tissue

Lymphoid follicles cluster in the terminal rectum of various animal species and of man and hence this site may be important in the development of immune responses to pathogens. For the induction of immune responses at mucosal sites, interplay is required between various cell types performing functions ranging from antigen-sampling cells via antigen-presenting cells to antigen-specific lymphocytes. Therefore, we have characterised the cell populations and relevant functioning of follicle-associated epithelium (FAE) and associated follicles in the terminal portion of rectum in cattle as a representative mammal. Immunohistochemical studies of this region identified immune cell subsets (CD4+, CD8+, WC 1+gammadelta, CD2+, CD 21+ and CD 40+ cells) characteristic of an immune-inductive site. Examination of FAE identified a subset of cells with structural and functional features of antigen-sampling M-cells. Cells of the FAE and adjacent follicle-associated crypts expressed vimentin and a subset of these cells internalised microparticles, a further attribute of M-cells. The FAE cells were phenotypically heterogeneous and therefore the function and phenotype of these cell subsets requires further characterisation, particularly with respect to their potentially important role in the interaction of hosts with pathogens and the development of immune 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.

A comparison of larval development and mucosal mast cell responses in worm-naïve goat yearlings, kids and lambs undergoing primary and secondary challenge with Teladorsagia circumcincta

Larval development, mucosal mast cell (MMC) and eosinophil responses in worm-nai;ve lambs, yearling goats and goat kids were compared using two different experimental challenge regimes involving oral administration of infective Teladorsagia circumcincta L(3). Experimental challenge regimes enabled primary and secondary immune responses in the two species to be compared. Goats carried higher worm burdens than lambs and there were significant differences in the stages of development attained by the larval challenge that established in the two species. Possible physiological reasons for these differences are discussed. There were also differences in the establishment and development of larvae in individual yearlings which may indicate the development of a weak age-related immune response. Quantitative analysis of MMC and globule leukocyte (GL) recruitment and functional activity in the form of mast cell-specific proteinase (MCP) production demonstrated differences between the species with goat tissues containing significantly higher numbers of GL and lower concentrations of MCP than the lambs. Quantitative analysis of blood and tissue eosinophil responses failed to demonstrate any significant differences in either species under the two challenge regimes.

IgE antibody during infection with the ovine abomasal nematode, Teladorsagia circumcincta: primary and secondary responses in serum and gastric lymph of sheep

A monoclonal antibody to ovine IgE was employed in an ELISA to investigate the IgE antibody responses in serum and gastric lymph to a primary infection of Teladorsagia circumcincta, and following challenge in previously infected sheep. During a primary response, IgE antibody to antigens derived from the infective third stage (L3) and adult (L5) worms were negligible, with low levels of IgE antibody detected in serum and lymph. In contrast, there was a pronounced IgE antibody response in 2/4 sheep to L3 antigens during 2-8 days after challenge of previously infected animals but low levels of IgE antibody to L5 antigens. This response was confirmed in a second but similar experiment, where relatively high levels of IgE antibody was detected to antigens from L3. Antibody levels were higher in lymph than in serum from the same animals, and Western blots of L3 antigen following SDS-PAGE under reducing conditions revealed several bands of MW26-96KD which reacted with the IgE antibody from gastric lymph. Immunohistochemical staining indicated that these IgE antibodies may be reacting with allergens associated with the surface cuticle of the worms.

The isolation and purification of a dual specific mast cell-derived protease from parasitised caprine jejunal tissue

A mast cell granule protease has been isolated and purified from nematode-infected caprine jejunal homogenate by FPLC techniques and termed Goat Mast Cell Protease (GMCP). The purification steps were monitored for proteolytic activity against the synthetic substrate carboxybenzoyl-L-lysine thiobenzyl ester (BLT) and the presence of a homogenous protease preparation in the final sample was shown by SDS-PAGE electrophoresis. This protease was compared with enzymatic activity from isolated mucosal mast cells, which demonstrated the putative mast cell-derived source of the purified enzyme. Rabbit antiserum was raised against the protease and through the use of immunohistochemistry and Western blotting techniques the mast cell origin of the protease was confirmed. NH2-Terminal amino acid sequence analysis demonstrated a high degree of homology between GMCP and other previously isolated mast cell proteases including sheep mast cell protease (SMCP). Substrate analysis showed that GMCP also had an unusual dual chymotrypsin-like and trypsin-like activity similar to SMCP and bovine duodenase.

The effects of recombinant ovine interleukin-3 and recombinant ovine stem cell factor on the growth and mediator expression of caprine and ovine bone marrow-derived mast cells

The growth of ovine and caprine mast cells in bone marrow cultures has been achieved using recombinant ovine interleukin-3 (rOvIL-3) and recombinant ovine stem cell factor (rOvSCF). After approximately 2-3 weeks' growth in optimal concentrations of either rOvIL-3 alone or a combination of rOvIL-3 and rOvSCF, the majority of the cells produced in bone marrow culture from both species were mast cells. The significant increase in the total numbers of cells and survival times of the cultures when both cytokines were present compared to either alone, indicated synergy between rOvIL-3 and rOvSCF on mast cell growth. Ovine and caprine cells cultured in rOvIL-3 alone produced a four-fold increase in cell numbers compared with medium only controls. The resulting cultures contained up to 52% mast cells by day 18 and had a lifespan of 3-4 weeks. In contrast, cells from both species grown in both rOvIL-3 and rOvSCF produced up to six times more cells than the equivalent rOvIL-3 stimulated cultures, contained up to 69% mast cells by day 21 and could be maintained for at least 6 weeks. Ovine cells grown in rOvIL-3 alone or rOvIL-3 and rOvSCF contained significantly more aryl-sulfatase and serine protease but similar amounts of beta-hexosaminidase compared with caprine cells during the second week of culture. There were no significant differences in the granule-associated mediator content of cells from either individual species grown in rOvIL-3 alone compared with those grown in rOvIL-3 and rOvSCF during the first 21 days of culture.

A comparison of the mast cell and eosinophil responses of sheep and goats to gastrointestinal nematode infections

The mucosal mast cell and eosinophil responses of goats and sheep to a mixed gastrointestinal nematode infection were compared. Groups of eight does and nine ewes, previously maintained on pasture and treated with anthelmintic when they were housed and five worm-free lambs were challenged with 10,000 Trichostrongylus vitrinus third stage larvae (L3) and 10,000 Teladorsagia circumcincta L3. Eleven days after challenge, the ewes had significantly (P < 0.001) lower burdens of abomasal and intestinal worms than the does or naive lambs, but significantly higher (P < 0.001) tissue concentrations of mast cell proteinase. Toluidine blue-stained sections indicated a paucity of mast cells in the does compared with the ewes, whereas the immunolocalisation of sheep mast cell proteinase revealed similar numbers of stained cells in the two species. This discrepancy was due to the relatively high proportion of globule leucocytes (77 and 91 per cent in the jejunum and abomasum, respectively) in the does compared with the ewes (7 and 24 per cent in the jejunum and abomasum, respectively). No differences were detected between the numbers of circulating or tissue eosinophils in the ewes and does.

Altered expression of mast cell proteases in the rat. Quantitative and immunohistochemical analysis of the distribution of rat mast cell proteases I and II during helminth infection

Expression of mast cell granule protease is regulated in a tissue-specific fashion in the rat. The granule chymases rat mast cell proteases I and II (RMCP I and II) predominate in non-mucosal and mucosal sites, respectively. Intestinal mastocytosis, a T cell-mediated phenomenon associated with enteric nematodiasis, is accompanied by massive local expression of RMCP II and by release of this protease systemically into blood. The present observations, where both RMCP I and II have been quantified by ELISA and immunolocalized by paired fluorescence, show that the expression of both proteases in parasitized rats is profoundly altered at sites distant from infection. Thus, RMCP II-containing cells are recruited to liver and thymus, and in the thymus there is a > 2-fold increase in concentration of RMCP I. The latter protease is depleted from bone marrow and mesenteric lymph node early during infection, but concentrations of RMCP I in trachea/larynx, lung, and skeletal and cardiac muscle are increased. Increased mast cell counts in intestine, lung and liver are highly correlated with tissue concentrations of RMCP II.

Mapping of the rat mast cell granule proteinases RMCPI and II by enzyme-linked immunosorbent assay and paired immunofluorescence

The distribution of the rat mast cell granule proteinases, rat mast cell proteinase I and II (RMCPI and II respectively) has been determined in rat tissues with the aid of highly sensitive and specific enzyme-linked immunosorbent assays (ELISA) and paired immunofluorescence. The major source of RMCPII is the gastrointestinal tract, although low concentrations were also detected in non-mucosal sites including thymus, mesenteric lymph nodes, liver, bone marrow, heart, kidney and spleen. Cellular localization by paired immunofluorescence showed that most cells contained either RMCPI or RMCPII, although a minor subpopulation in which individual cells contained both proteinases was also identified in a few tissues. RMCPII-containing cells predominated at mucosal surfaces but were also found in non-mucosal tissues. Individual cells expressing both RMCPI and II were present in lung, liver mesenteric lymph node and submucosa of stomach and were occasionally represented amongst serosal cells from the peritoneal cavity. Connective tissue mast cells of skin and tongue were identified as major sources of RMCPI, although this proteinase was widely distributed in all tissues examined. The present study demonstrates the heterogeneity of mast cell proteinase phenotypes in the rat and emphasises the difficulties in determining mast cell subtypes on tissue location alone.

Observations on the pathogenesis of Chlamydia psittaci infection of pregnant sheep

Susceptible pregnant sheep were infected with Chlamydia psittaci at different stages of early and mid-gestation. Placentas and foetuses were examined by microbiological, serological, histopathological and immunochemical methods at various intervals thereafter. While ewes were susceptible to infection from early gestation onwards and infections of placentas and foetuses occurred from about 60 days gestation (dg), pathological changes were not detected until after 90 dg. These changes consisted of initial rapid replication of C. psittaci in the trophoblast at the limbus of the placentomal hilus, leading to local necrosis and contiguous spread of infection to involve the cotyledonary and intercotyledonary placenta and apposing endometrium. Foetal pathology consisted of focal necrosis in liver and other organs suggestive of embolic dissemination of infection from the placenta. An early foetal immune response was detected including the demonstration of IgM and IgG antibody to C. psittaci and quantitative evidence of a B cell response to infection. Pathogenetic mechanisms are discussed.

Distribution of intestinal mast cell proteinase in blood and tissues of normal and Trichinella-infected mice

A sensitive and specific enzyme-linked immunosorbent assay (ELISA) was developed for mouse intestinal mast cell proteinase (IMCP). Specificity was demonstrated by the absence of immunoreactivity with extracts of isolated serosal mast cells (SMC), or with high concentrations (50 micrograms/ml) of the antigenically similar rat mast cell proteinases I or II. The small and large intestines in normal mice were the major sources of IMCP, there being little or no IMCP in non-mucosal tissues. Concentrations of IMCP in normal (non-parasitized) mice were low, but were increased 100-1000-fold intestines of mice infected 10 days earlier with Trichinella spiralis. The kinetic response of secreted IMCP into the blood of mice following infection with T. spiralis was also studied. Systemic release of IMCP coincided with the immune expulsion of adult worms from the intestine, and peak concentrations (9.45 micrograms/ml IMCP) occurred 9 days after infection. The tissue distribution of IMCP, its secretion into blood, and its enteric accumulation during parasite infection, are consistent with a mucosal mast cell (MMC) source for IMCP. The results are discussed in the context of similar findings for rat mast cell proteinase II.

Granule proteinases define mast cell heterogeneity in the serosa and the gastrointestinal mucosa of the mouse

In order to define further mast cell heterogeneity in the mouse, affinity-purified antibodies against a 28,000 MW serine proteinase from mouse intestinal mast cells (IMCP) and against rat mast cell proteinase I (RMCPI) were used to characterize mast cell cytoplasmic granules immunohistochemically. On Western blot, anti-IMCP cross-reacted with RMCPI and with a 25,000 MW antigen from isolated mouse serosal mast cells (SMC). Anti-RMCPI did not react with IMCP, although it identified the same 25,000 MW antigen from SMC. Isolated SMC (85-90% pure) lacked the 28,000 MW IMCP on Western blot, even though, immunohistochemically, the cells were stained with both anti-RMCPI and anti-IMCP. Anti-IMCP stained the granules of more than 85% of all mast cells detected with toluidine blue in the tongue or gastrointestinal mucosa. The specificity of anti-RMCPI which, in the rat, detects very few mucosal mast cells was almost identical to that of anti-IMCP for murine tongue and gastric and large intestinal mucosae, but a significant proportion of cells in distal jejunal, ileal and caecal mucosae were not stained with this antibody. The immunohistochemistry of the large numbers of mast cells recruited to jejunum following infection 10 days previously with 300 Trichinella spiralis muscle larvae was similar to that of uninfected control mice. The results show that considerable mast cell heterogeneity exists within the gastrointestinal mucosa of the mouse and indicate that there are both similarities and differences between mouse and rat in the distribution of mast cells and of their granule proteinases.

The generation of ovine bone marrow-derived mast cells in culture

Ovine mast cells generated in vitro are morphologically and biochemically similar to mast cells localized to the gastrointestinal tract in vivo. Bone marrow (BM)-derived haemopoietic precursor cells were cultured in the presence of conditioned medium (CM) prepared from in vitro-activated lymphocytes from nematode-infected sheep. Mast cells developed rapidly after 2 weeks of culture and could persist for 2-3 months. The presence of sheep mast cell proteinase (SMCP) in the cultured cells correlated with the number of morphologically recognizable mast cells by Leishman-Giemsa staining and is definitive as, in vivo, this enzyme is unique to mast cells. The content of SMCP per cell increased as the cultures developed. In vivo, increased serum concentrations of SMCP are associated with mast cell function at the site of nematode infection. The availability of the cultured cells should now facilitate mast cell biochemical and functional studies.

Infantile hypertrophic pyloric stenosis: a review of 222 cases

The results of 222 cases of hypertrophic pyloric stenosis operated on at the Princess Margaret Hospital for Children in Perth, from 1979 to 1984, have been reviewed. There were no deaths, but there was a 7% incidence of wound infection and a 72% incidence of postoperative vomiting. Staphylococcus Aureus was cultured from 62% of the infected wounds. Prophylaxis against Staphylococcus Aureus infection and delayed introduction of feeding are suggested.

Mannosidosis in Aberdeen Angus cattle in Britain

Mannosidosis, an inherited and lethal lysosomal storage disease of Aberdeen Angus cattle, was diagnosed on a farm in north-east Scotland. Two affected calves were examined in detail. Both were poorly grown and ataxic, though the intention tremor and aggression considered characteristic of the disease were not recorded. Histological examination revealed typical vacuolation of nerve cells, fixed macrophages and epithelial cells of the viscera. Deficiency of the enzyme alpha mannosidase was demonstrated. The epidemiology of the disorder in Scotland is considered and control methods indicated.

45,X/47,XYY mosaicism

This paper describes and discusses the clinical and cytogenetic findings in an infant with an unusual sex chromosome abnormality 45X/47XYY.