The MHC class II region and resistance to an intestinal parasite in sheep

SUMMARY: RFLP analysis was used to investigate the effect of genetic variation in the Major Histocompatibility Complex (MHC) class II region on resistance of sheep to the intestinal parasite Trichostrongylus colubriformis, using faecal egg count (fec) as the measure of resistance. RFLP analysis of DNA from 335 sheep with the restriction enzymes TaqI, PvuII and HindIII, and DRB, DQA and DQB human class II MHC cDNA clones, revealed 238 bands, of which 233 were polymorphic. Sixteen bands were associated with a significant effect on fec, when analysed using a mixed model, best linear unbiased prediction statistical methods. However, when p values were corrected for the number of bands tested the associations were no longer significant. While no individual band had a significant effect on fec, Fisher's X(2) test of the distribution of p-values showed that RFLP bands, when considered together, do account for a significant proportion of variation in fec. One hundred and thirteen offspring from 11 halb-sib families were classified according to which MHC haplotype they had inherited from their sire. While there was overall no convincing statistical evidence of an effect of MHC haplotype on resistance, results in one family showed evidence for a repeatable MHC effect. ZUSAMMENFASSUNG: Die MHC-Klasse II Region und Resistenz gegenüber Darmparasiten beim Schaf RFLP Analyse betrifft die Auswirkung genetischer Unterschiede im Haupthistokompatibilit?ts-Komplex (MHC) Klasse II Region auf Resistenz von Schafen gegen den Darmparasiten Trichostrongylus colubriformis, wobei die f?kale Eizahl (fec) als Ma? der Resistenz verwendet worden ist. Die RFLP-Analyse der DNA von 335 Schafen mit Restriktionsenzymen TaqI, PvuII und HndIII und DRB, DQA und DQB menschlicher Klasse II MHC cDNA Klone ergab 238 Bande, wovon 233 polymorph waren. 16 Bande waren mit einer signifikanten Wirkung auf fec verbunden, wobei zur Analyse das gemischte Modell der BLUP verwendet worden ist. Allerdings, nach Korrektur der p-Werte für die Zahl der geprüften Bande zeigt sich die Assoziation nicht l?nger als signifikant. W?hrend kein individuelles Band eine signifikante Wirkung auf FEC zeigte, ergab Fisher's test hinsichtlich Verteilung der p-Werte Signifikanz bei Gesamtbetrachtung. 113 Nachkommen von 11 Halbgeschwister-Familien wurden nach dem MHC Haplotyp des Vatertieres klassifiziert. Es ergab sich kein insgesamt überzeugender statistischer Hinweis auf Wirkung der MHC Haplotypen, doch in einer Familie Hinweis auf wiederholbare MHC Effekte.     

Monoclonal antibodies to sheep MHC class I and class II molecules: biochemical characterization of three class I gene products and four distinct subpopulations of class II molecules

The availability of a panel of monoclonal antibodies to sheep MHC class I and class II gene products has allowed for the first time an assessment of the relative complexity of the sheep MHC. By using four monoclonal antibodies to MHC class I, and seven monoclonal antibodies to MHC class II molecules together with one-dimensional SDS-PAGE, sequential immunoprecipitation and 2-dimensional gel analysis, three class I gene products and four distinct subsets of class II molecules have been identified. Sheep class I molecules showed heterogeneity on 2-dimensional gels and as in mouse and man, represented the products of at least three different non-allelic class I genes. Interestingly, the sheep beta 2 microglobulin molecule also displayed heterogeneity, consistent with either two primary gene products or allelic variation. Four sheep class II monoclonal antibodies identified distinct, non-overlapping subsets of sheep class II molecules of Mr 32-36 K (alpha chain) and 25-28 K (beta chain). These class II molecules were co-expressed on sheep B lymphocytes and represented the primary products of different sheep MHC class II genes. The class II molecules within three of these subsets displayed allelic polymorphism essentially restricted to their beta polypeptides, while the fourth subset of class II molecules showed allelic variation in both their alpha and beta polypeptides. The results of this study represent the first evidence for gene duplication and heterogeneity within the sheep MHC. The identification of three primary class I gene products and four distinct subsets of class II molecules suggests three class I loci and up to four distinct class II subregions within the sheep MHC. Potentially large numbers of allelic variants of these different gene products may be expressed in normal sheep.     

Detection of porcine MHC class II antigens in different immunoassays

A monoclonal antibody (Mab), Mab 4-24-11, to human class II major histocompatibility antigens has been tested in commonly used immunoassays for detection of porcine class II major histocompatibility antigens (SLA-D). In a radioimmunoprecipitation assay, Mab 4-24-11 reacted with proteins from mitogen-stimulated porcine mononuclear cells (MNC). The molecular weights of the precipitated proteins were approximately 34 and 28 Kd. In indirect immunofluorescence, approximately 25% of porcine MNC in suspension reacted with Mab 4-24-11. This percentage diminished to 14% when Ig bearing MNC were removed, while it increased to 36% when adherent MNC were enriched. Thus, it was concluded that Mab 4-24-11 cross-reacts with SLA-D. In a immunohistochemical study, Mab 4-24-11 reacted with cells in acetone fixed cryostat sections from the gastric mucosa and endometrium. These properties of Mab 4-24-11 make it useful as a tool for further studies on the porcine immune system.     

MHC class II expression in the bovine mammary gland.

The distribution of major histocompatibility complex (MHC) class II positive cells within the connective tissue and the epithelium of the involuted bovine mammary gland has been determined. The effect of intramammary administration of the antigens ovalbumin and formalin killed Streptococcus uberis on the distribution pattern has also been investigated. Infusion of formalin killed S. uberis increased cellular expression of class II antigens when compared with quarters either infused with ovalbumin, not infused at all, or from which minor pathogens had been isolated. The increased expression occurred particularly in the area of the gland cistern-secretory tissue junction.     

Capillariasis in a vulture guinea fowl

A case of capillariasis was diagnosed in a 5-yr-old male vulture guinea fowl (Acryllium vulturinum) with clinical signs of weakness, anorexia, and vomition. Necropsy revealed that the bird was severely emaciated and the liver was congested. The entire mucosa of the crop and esophagus was severely thickened as a result of the presence of fibrinonecrotic white plaques mixed with numerous nematodes. Histopathology of the crop and esophagus revealed multifocal areas of necrosis of the mucosa, severe inflammation, and squamous cell hyperplasia. Numerous nematode adults, larvae, and eggs consistent with the morphology of Capillaria sp. were found within the mucosa. The nematodes were identified as Capillaria contorta. Similar cases of capillariasis have been diagnosed in other vulture guinea fowl.     

Eggshell of the domestic guinea fowl

1. Physical characteristics of eggs of the domestic guinea fowl, Numida meleagris galeata, were measured and compared with those of its wild counterpart and with other birds using allometric relationships.

2. The shell thickness increased and the area density of pores decreased from the blunt to the pointed end of the egg. During incubation, shell thickness decreased, but the shell diffusive conductance to water vapour (G_H2O) remained constant.

3. Fresh egg mass (m₀), length and breadth of the egg, G_H2O and specific water vapour conductance, spG_H2O (G_H2O per g of m₀ ), were affected by the age of the laying flock.

4. Eggs of the domestic guinea fowl were bigger and heavier than eggs of the wild one.

5. Allometry showed that guinea fowl eggs differ from those of the other birds by their greater shell thickness and density of pores. However spG_H2O was normal, the thickness of the shell being compensated for by a greater density of pores for gas exchanges.     

MHC class II expression by follicular keratinocytes in canine demodicosis--an immunohistochemical study

MHC class II proteins present fragments of extra cellular antigen to stimulate CD4(+) T lymphocytes. Aim of this study was the detection of MHC class II antigens on different cutaneous cells in canine demodicosis. Histopathological and immunohistochemical examination of skin biopsies from 44 dogs with demodicosis is reported. The control group consisted of skin biopsies taken from 10 necropsied dogs without obvious skin lesions. The immunohistological assessment of the MHC class II expression revealed MHC class II proteins on different cell types of infiltrating inflammatory cells, i.e. APCs (antigen-presenting cells), macrophages, T lymphocytes and B lymphocytes. The plasma cells, however, only showed expression in 32 (73%) of 44 cases. Generally it was noticeable that most plasma cells but never all of them expressed MHC class II. Neutrophils, mast cells and eosinophils were MHC class II negative. Furthermore, in 39 biopsies (89%) from dogs with demodicosis MHC class II positive follicular keratinocytes were found. The control group did not show MHC class II expression on epithelial cells. Concerning the endothelial cells, a total of 25 biopsies (57%) showed MHC class II expression in which different vascular plexuses were affected by staining. This examination shows that MHC class II expression in the skin of dogs suffering form demodicosis is elevated. Especially the MHC class II expression by follicular keratinocytes seems to be conspicuous. We hypothesize that this is in association with the development and the maintenance of follicular inflammation.     

MHC class II expression by mast cells in the genital tract of cows

This work examined the presence of MHC class II molecules expressing mast cells in oviduct, uterus and vaginal tissues in cows. The tissue samples of five cows were collected from a local slaughterhouse. Toluidine blue pH 0.5 (TB) and avidin-biotin peroxidase complex (ABC) staining procedures applied to adjacent sections from tissue samples. It was determined that some TB + cells were also gave positive reaction with strept ABC staining for MHC II molecules. To our knowledge this is the first evidence indicating the presence of MHC class II molecules expressing mast cells in the cow.     

Chemical composition of the Pearl Grey guinea fowl

1. The growth of the chemical components of the body of the Pearl Grey guinea fowl from hatching till 127 days of age was evaluated in this study.

2. The Gompertz equation is suitable to describe the growth of the different chemical components over time.

3. Body and feather fat, respectively, were estimated by subtracting the predicted weights of all other components from those of body and feather weights. This leads to an overestimation of body fat content, and erroneous estimated values for feather fat.     

Adenoviral pancreatitis in guinea fowl (Numida meleagris)

Necrotizing pancreatitis was observed in 2-week-old Guinea fowl submitted for necropsy and histopathology. Intranuclear inclusion bodies seen histologically in acinar epithelium were examined by electron microscopy and found to contain viruses resembling adenovirus. Adenovirus was isolated in embryonated eggs from the pancreata of affected birds. The adenovirus isolated was not neutralized by chicken antisera developed against 10 known serotypes of group 1 avian adenoviruses.     

Identification of two independent MHC class II antigens in a bovine lymphoblastoid cell line

Bovine major histocompatibility complex (MHC) class II antigens were investigated using monoclonal antibodies (MoAbs) with known MHC class II specificities in other species. Thirty-four MoAbs were tested for reactivity with bovine peripheral blood mononuclear (PBM) cells and the bovine lymphoblastoid cell line, BL3, by flow cytometry. Twenty-seven of 31 MoAbs tested, reacted with BL3 cells, and 22 of 25 MoAbs tested with PBM cells were reactive. MoAbs that reacted with BL3 cells were used to immunoprecipitate class II molecules from BL3 lysate labeled with [35S]methionine. Using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and autoradiography, many MoAbs were found to immunoprecipitate a single band of approximately 31,000 relative mass (Mr). MoAbs yielding successful immunoprecipitations and with known antigen specificity in other species were then used in sequential immunoprecipitations and two dimensional (2-D) non-equilibrium pH gradient electrophoresis (NEPHGE). The HLA-DR specific MoAb H4 and the predominantly HLA-DQ specific MoAb CC11.23 were used to identify the presence of two independent antigens in BL3 cell lysate. These class II molecules consist of alpha and beta chains.     

Water uptake by eggs of mallards and guinea fowl

The cuticle is the principal barrier to water uptake by the eggs of mallard, guinea fowl and the domestic fowl. The fat present in the cuticle of mallard eggs makes a large contribution to repelling water dropped on to the shell but only a small contribution to resisting water movement into eggs exposed to hydrostatic pressure. Although the thickness of the shells of the eggs of the birds mentioned above varied extensively, there was no obvious correlation of the length of the pore canal with the amount of water taken up by an egg.     

Optimum incubation conditions of the domestic guinea fowl egg

1. During artificial incubation of 8000 guinea fowl eggs, the effects of temperature, relative humidity, rate of inflowing air and age of the laying flocks were determined.

2. Total duration of incubation was divided into setter (0 to 24 days) and hatcher (25 to 28 days) periods. Eggs transferred at the end of the setter period, (ET, % of fertile eggs) and hatching rate (HR, % of transferred eggs) were calculated, as well as the total hatching rate expressed as percentage of fertile eggs.

3. In the range 36 to 39°C, temperature affected significantly (P< 0.001) ET and HR, with optima at 37.2 and 37.0°C ± 0.1°C respectively.

4. During incubating period, relative humidity in the range 40 to 64% (water vapour partial pressure, Ph₂o ⁼ 17 to 34 Torr at 36 to 39°C), significantly (P< 0.001) affected the total diffusive water loss and hatchling mass, both expressed as percentage of fresh egg mass. ET was significantly affected by water loss, the highest ET being for water loss of 13.3 ± 0.5%. Optimal relative humidity was calculated to be 48 to 52% (Ph₂o = 23 to 25 Torr at 37.2°G).

5. The rate of inflowing air significantly (P< 0.001) affected HR, with an optimum at 3.1 Lstpd/(h . egg).

6. The age of the laying flock significantly (P< 0.001) increased water loss; this was explained by a parallel increase of the mass specific shell conductance to water vapour.

7. Finally optimum incubation conditions were deduced, giving total hatching rates of 78 to 81% of fertile eggs, improving by 5 to 8% the best results obtained routinely in commercial practice.     

Molecular characterization of reticuloendotheliosis virus insertions in the genome of field and vaccine strains of fowl poxvirus

Evidence of the widespread occurrence of reticuloendotheliosis virus (REV) sequence insertions in fowl poxvirus (FPV) genome of field isolates and vaccine strains has increased in recent years. However, only those strains carrying a near intact REV provirus are more likely to cause problems in the field. Detection of the intact provirus or REV protein expression from FPV stocks has proven to be technically difficult. The objective of the present study was to evaluate current and newly developed REV and FPV polymerase chain reaction (PCR) assays to detect the presence of REV provirus in FPV samples. The second objective was to characterize REV insertions among recent "variant" FPV field isolates and vaccine strains. With REV, FPV, and heterologous REV-FPV primers, five FPV field isolates and four commercial vaccines were analyzed by PCR and nucleotide sequence analysis. Intact and truncated REV 5' long terminal repeat (LTR) sequences were detected in all FPV field isolates and vaccine strains, indicating heterogeneous REV genome populations. However only truncated 3' LTR and envelope sequences were detected among field isolates and in one vaccine strain. Amplifications of the REV envelope and 3' LTR provided strong evidence to indicate that these isolates carry a near intact REV genome. Three of the four FPV vaccine strains analyzed carried a solo complete or truncated 5' LTR sequence, indicating that intact REV provirus was not present. Comparison of PCR assays indicated that assays amplifying REV envelope and REV 3' LTR sequences provided a more accurate assessment of REV provirus than PCR assays that amplify the REV 5' LTR region. Therefore, to differentiate FPV strains that carry intact REV provirus from those that carry solo 5' LTR sequences, positive PCR results with primers that amplify the 5' LTR should be confirmed with more specific PCR assays, such as the envelope, or the REV 3' LTR PCR.     

Helminths of guinea fowl (Numida meleagris) in Bashkir ASSR

Guinea fowl from different regions of Bashkir Autonomous Soviet Socialist Republic (BASSR) were examined for helminths. Of the 547 fowl examined, 451 (82.4%) harboured at least one species of helminth. A total of 56,772 helminths were collected and classified. Of this number seven were found to be trematodes, 25 cestodes and 56,740 nematodes. Five species of helminths were identified. Amongst infected birds, trematodes were present in three (0.7%), cestodes in eight (1.8%) and nematodes in 451 (100%). Of all recorded helminths, the incidence of Heterakis gallinarum (Gmelin, 1790) was highest. Pre-patent periods for seven species of trematodes were observed in guinea fowl for the first time.     

Molecular detection and characterization of fowl adenovirus associated with inclusion body hepatitis from broiler chickens in Egypt

Tropical Animal Health and Production - A case-control study was performed to assess prescence of inclusion body hepatitis (IBH) caused by fowl adenoviruses (FAdVs) at Kafr EL-Shiekh Governorate,...