Immunoblot analysis of IgG antibody response to Sarcoptes scabiei in swine

This study was performed to determine the frequencies and specificities of IgG antibodies binding to component of Sarcoptes scabiei extracts in swine with hypersensitive and chronic mange. The hypersensitive form is characterised by pruritus and the presence of small red papules over the flanks and belly. The chronic form is characterised by crusts, which contain large numbers of mites and are attached to the skin; the lesions are most commonly found on the internal pinna extending into the auditory canal. S. scabiei mite extract was separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis with subsequent immunoblotting. IgG-binding proteins were detected with individual sera from 30 hypersensitive and 21 chronically infected pigs; eight "Specific Pathogen Free" pigs were used as negative controls. Seven protein bands with molecular weights ranging from >220 to 30 Kilodalton (KDD) (>220, 218, 110, 80, 66, 52, 36 KDD) strongly bound with IgG antibodies; five out of these seven components (218, 110, 80, 66, 52 KDD) bound also with sera from negative pigs. There is a statistically significant difference in the antigenic recognition spectra between hypersensitive and chronically infected pigs; component of >220 KDD is more frequently recognized by chronically infected pigs (P=0.0006, chi(2)=11.74), in contrast component of 36 KDD is more frequently recognized by hypersensitive pigs (P=0.001, chi(2)=10). Our results clearly indicate there is a difference in the reactivity to antigenic peptides/proteins of S. scabiei mite between hypersensitive and chronically infected pigs, and revealed that only two antigens may be considered S. scabiei-specific and used for diagnostic purposes in swine.     

新疆美利奴羊对绵羊慢病毒的品种敏感性实验

绵羊慢病毒 ( Ovine lentivirus,Ov LV) ,属逆转录病毒科 ( Retroviridae)、慢病毒亚科 ( Lentivirinae) ,它的原型病毒为冰岛的梅迪 -维思纳病毒 ( maedi- visnavirus,MVV) ,属强毒株 ,引起的疾病称梅迪 ( mae-di,意为呼吸困难 )。绵羊进行性肺炎病毒 ( Ovineprogressive pneumonia virus,OPPV)为 Ov LV的美国株 ,属弱毒株 ,引起的疾病称为绵羊进行性肺炎( OPP)。MVV和 OPPV属 Ov LV的 1型或溶解型 ,此型 Ov LV(包括 MVV、OPPV与其他国家或地区的病毒株 )可引起淋巴组织样间质性肺炎 ( LIP)与肺淋巴滤泡增生、淋巴细胞性…     

新疆绵羊群体对绵羊慢病毒的品种敏感性研究

不同品种的绵羊对绵羊慢病毒(Ovine lentivirus，OvLV)的敏感性程度取决于绵羊的品种和OvLV的毒力(强度株、弱毒株)。对某一毒力已知的病毒株的敏感程度，则取决于绵羊的品种，称为品种敏感性(敏感品种、低敏感性品种)。0vLV的品种敏感性历来受到研究者的重视。     

Detection of antibodies to ovine lentivirus using recombinant capsid and transmembrane proteins

The coding sequences of the capsid protein p25 and transmembrane protein of Maedi-Visna virus were amplified using polymerase chain reaction and cloned into the plasmid expression vector pRSET-B. Both DNA constructs expressed proteins tagged with polyhistidine. The recombinant proteins were purified using Ni-NTA agarose and used in immunoblot to detect antibodies against Maedi-Visna virus. A total of 260 ovine serum specimens was analysed. The total number of p25-positive sera was 111 (42.7%). Higher sensitivity was achieved with rTM antigen, which detected antibodies in 118 (45.4%) sera. The combination of both recombinant proteins as antigens resulted in higher sensitivity of serological detection compared to whole virus antigen.     

新疆美利奴羊对绵羊慢病毒自然感染的品种敏感性研究

用绵羊进行性肺炎病毒(OPPV)实验感染新疆美利奴羊的研究业已证实,新疆美利奴羊对OvLA美国株(OPPV)的敏感性很低,且呈现亚临床性感染。本项目通过对自然感染绵羊慢病毒新疆株的新疆美利奴羊的长期研究,试图进一步证实新疆美利奴羊是对OvLV的低敏感性品种。     

Serum and abomasal antibody response of sheep to infections with Haemonchus contortus

Serum and abomasal IgA, IgG and IgM antibody response against adult worm, L3 and egg antigens of Haemonchus contortus was monitored by the ELISA technique after one or two infections with this nematode. Following the first infection, antibody levels in serum did not change materially. After administration of a challenge dose of infective larvae, antibodies of the three immunoglobulin classes in infected animals rose slightly, but this rise appeared later than the fall in the faecal egg counts. In contrast, in abomasal mucosa, IgA anti-larval antibody levels, which did not increase materially after the primary infection, rose rapidly after a transient inhibition when sheep were challenged. A close temporal relationship was observed between the rise in local anti-worm IgA antibodies and the self-cure reaction, but antibody levels fell rapidly after worm diminution. The local antibody response was thus considered to be related to immunity of sheep to H. contortus.     

绵羊慢病毒北疆株自然感染新疆美利奴羊的病理学

绵羊慢病毒 ( ovine lentivirus,Ov LV)有 3型。1型为溶解型 ,主要有流行于欧洲的梅迪 -维斯纳病毒( maedi- visna virus,MVV) ,即原型病毒冰岛株 ,以及美国的绵羊进行性肺炎病毒 ( ovine progressivepneumonia virus,OPPV) ,即 Ov LV美国株等。1型可引起淋巴组织样间质性肺炎 ( lymphoid intersti-tial pneumonia,LIP)与淋巴滤泡形成、淋巴细胞性乳腺炎和非化脓性脑 (白质 )炎 ,OPPV及某些MVV株还可引起非化脓性关节炎。2型为非溶解型或持久感染型 ,持久感染细胞培养但不溶解细胞单层 ,只形成极少量的合胞体。 2型可引起轻度 LI…     

Circulating antibody response to Eimeria tenella oral and subcutaneous infections in chickens

Immune responses in chickens to Eimeria tenella using oral and subcutaneous routes of infection were investigated. The results obtained indicated that sporulated oocysts inoculated subcutaneously in doses up to 50 000 oocysts per bird were not fatal to 21-day-old chicks. Subcutaneous inoculation of oocysts was found to be less immunogenic than oral administration. The dynamics of the antibody responses were different for the two routes of infection. Orally administered oocysts stimulated a dramatic primary increase in the serum antibody titre with a tendency towards a decrease in the titre 14 days post infection irrespective of second infections at that time. However, a third oral dose of oocysts stimulated a slight increase in antibody titre. Two doses of oocysts injected subcutaneously induced only a slight increase in serum antibody titre. Such a low titre was dramatically increased following a subsequent oral dose of oocysts. Antibodies specific to E. tenella are IgM and IgG immunoglobulins. IgA immunoglobulin was not investigated.     

Analysis of the humoral immune response to Oestrus ovis in ovine

Antibody responses (IgG, IgM and IgA) against Oestrus ovis were analyzed in sheep and in first year grazing lambs from Sardinia (Italy) by an indirect-enzyme-linked immunoassay test and L2 O. ovis excretory/secretory antigens. Serum samples from 208 sheep were obtained prior to be slaughtered, and then heads were removed and cut open along their longitudinal axis to collect the parasites from the nasal cavities, turbinates and sinus. Besides this, blood samples were monthly collected from the lambs of G-1 (maintained under field conditions) and the lambs of G-2 (kept housed since birth to avoid Oestrus infestations) throughout a year. In the sheep, a positive significant correlation was observed between the number of first instar O. ovis larvae and the values of IgM, and between the second instar larvae and the IgG optical densities. In the lambs, all classes of antibodies increased significantly from July in G-1. The highest values of IgG were reached in September (IgG) and decreased in November-December. The IgM response peaked in November, and very low values of IgA were observed during the study. Matching these data with chronobiology of O. ovis in this region, we conclude that the first infection occurs on May, stimulating the production of humoral antibodies. The reduction of the IgG antibody levels starting from October means the beginning of the diapause while the IgM response seems to be associated to the presence of L1 in the nasal cavities. The data obtained led us to forecast an early treatment of the ovine on June-July, which should keep away from the maturation of O. ovis L1 larvae, avoiding the development of clinical lesions and interrupting the life cycle of this parasite.     

Production and purification of ovine anti-tetanus antibody

We used the ovine as bioreactor for the production and optimization of anti-tetanus toxin antibody. Four female sheep were immunized with human tetanus vaccine (TT-alum) every two weeks for 16 weeks, after which serum was collected and its titer was estimated by ELISA. The highest titer obtained was 39,000 IU ml-1. To optimize a purification protocol for ovine anti-tetanus toxin, we used four procedures; weak anion (DEAE-Sephadex), weak cation (CM-Sephadex), ammonium sulfate precipitation alone or in combination with caprylic acid. Fifty percent saturation with ammonium sulfate combined with caprylic acid gave us the highest yield of protein with specific activity and the purest Fab product.     

Antibody response of the ovine lymph node to experimental infection with an ovine abortion strain of Chlamydia psittaci

After primary infection with Chlamydia psittaci in the draining area of the popliteal lymph node, viable organisms could be isolated from the efferent lymph only before the primary immune response developed. The lymph antibody response, as assayed by the complement fixation and immunofluorescence (IF) antibody tests, showed a rise in titre that peaked approximately 2 weeks after infection. Immunoblotting revealed that antibodies produced during this period were predominantly directed against the major outer membrane protein (MOMP). In secondary infection of convalescent sheep, an elevated IF antibody titre, already present in the lymph and blood, could not be boosted. Viable organisms could not be isolated from these sheep. Antibodies produced reacted to 12-14 bands in the immunoblot profile including the MOMP band. These potentially immunoprotective antigens, particularly MOMP, should be considered as useful candidates for an improved vaccine against ovine enzootic abortion, in further investigations.     

Immune response to fungal infections

The immune mechanisms of defence against fungal infections are numerous, and range from protective mechanisms that were present early in evolution (innate immunity) to sophisticated adaptive mechanisms that are induced specifically during infection and disease (adaptive immunity). The first-line innate mechanism is the presence of physical barriers in the form of skin and mucous membranes, which is complemented by cell membranes, cellular receptors and humoral factors. There has been a debate about the relative contribution of humoral and cellular immunity to host defence against fungal infections. For a long time it was considered that cell-mediated immunity (CMI) was important, but humoral immunity had little or no role. However, it is accepted now that CMI is the main mechanism of defence, but that certain types of antibody response are protective. In general, Th1-type CMI is required for clearance of a fungal infection, while Th2 immunity usually results in susceptibility to infection. Aspergillosis, which is a disease caused by the fungus Aspergillus, has been the subject of many studies, including details of the immune response. Attempts to relate aspergillosis to some form of immunosuppression in animals, as is the case with humans, have not been successful to date. The defence against Aspergillus is based on recognition of the pathogen, a rapidly deployed and highly effective innate effector phase, and a delayed but robust adaptive effector phase. Candida albicans, part of the normal microbial flora associated with mucous surfaces, can be present as congenital candidiasis or as acquired defects of cell-mediated immunity. Resistance to this yeast is associated with Th1 CMI, whereas Th2 immunity is associated with susceptibility to systemic infection. Dermatophytes produce skin alterations in humans and other animals, and the essential role of the CMI response is to destroy the fungi and produce an immunoprotective status against re-infection. The resolution of the disease is associated with a delayed hypersensitive response. There are many effective veterinary vaccines against dermatophytoses. Malassezia pachydermatis is an opportunistic yeast that needs predisposing factors to cause disease, often related to an atopic status in the animal. Two species can be differentiated within the genus Cryptococcus with immunologic consequences: C. neoformans infects predominantly immunocompromised hosts, and C. gattii infects non-immunocompromised hosts. Pneumocystis is a fungus that infects only immunosupressed individuals, inducing a host defence mechanism similar to that induced by other fungal pathogens, such as Aspergillus.     

Economic analysis of vaccination applied to ovine listeriosis

An economic model for determining whether vaccination against a disease would be beneficial financially on individual farms is proposed; it is based on four pieces of information: the costs of a disease case including its treatment, the cost of vaccinating each animal including veterinary fees, the expected incidence of the disease, and the efficacy of the vaccine. The model was applied to ovine listeriosis, which is a serious disease problem in Norway. Vaccination appeared to be beneficial for the average sheep flock of 100 ewes which might expect two or more cases of listeriosis per year. Furthermore, the model suggests the ratio of the price of a single vaccination to the cost of a disease case can be used to plan more efficient vaccine field trials.     

Detection of chlamydial antibody by fetal serology--an aid to the diagnosis of ovine abortion.

Two serological tests (indirect immunofluorescence and enzyme-linked immunosorbent assay) were developed for the detection of fetal antibody to Chlamydia psittaci. Fetal blood and thoracic fluid from 126 field cases of suspected ovine chlamydial abortion were examined using both tests. Placenta and fetal tissues (lung, liver, and kidney) from the same animals were also examined by the following conventional diagnostic methods: isolation in McCoy cells, detection of chlamydial lipopolysaccharide (LPS), modified Ziehl-Nielsen staining, and direct fluorescent antibody staining of chlamydia in frozen cryostat sections. Seventy cases were positive by fetal serology, and of these, 68 were also positive by isolation and/or LPS detection. The remaining 56 cases had negative fetal serology, and of these, 39 were positive by isolation and/or LPS detection. Results indicate that fetal serology, although less sensitive than either isolation in McCoy cells or detection of chlamydial LPS antigen, may be of particular use when placenta is not available.     

The phagocytic cell response of the ovine lung to Pasteurella haemolytica

Conventionally-reared sheep were inoculated with (3.0 ± 0.6 × 10⁷) viable Pasteurella haemolytica type A1 by the intratracheal route and were killed immediately (0-time) or 2, 4, 12, 16, 24, 48 or 72 h later. Lung-wash cells and free bacteria were recovered by pulmonary layage.The number of recoverable bacteria tended to increase between 0-time and 4 h post-in-oculation (p.i.) then decline rapidly over the next 8 h. However, the rate of clearance was extremely variable and viable bacteria were recovered from $\text{3}\text{5}$ animals at 48 h p.i. and from $\text{1}\text{5}$ at 72 h p.i.In parallel with the clearance of the majority of the bacteria, total neutrophil numbers in the lung-wash rose to a peak of (36 ± 6) × 10⁸ cells/lung, which was, on average, 70-fold higher than 0-time levels. Their numbers remained constant from 12 to 24 h p.i. then fell to be 5-fold above 0-time levels at 72 h p.i. Macrophage numbers rose slowly throughout the experiment but most of the increase occurred between 24 and 48 h p.i. They reached a peak of (17 ± 11) × 10⁸ cells/lung at 48 h i.p. which was 3-fold higher than 0-time levels.     

Assessment of the ovine acute phase response and hepatic gene expression in response to Escherichia coli endotoxin

Lipopolysaccharide (LPS), a bacterial membrane endotoxin, induces a systemic inflammatory response (IFR) through the activation of blood monocytes and hepatic kupffer cells. These cells secrete pro-inflammatory cytokines, which subsequently activate the hypothalamic-pituitary-adrenal axis (HPAA) to release cortisol, an anti-inflammatory hormone that regulates the IFR and subsequent immune response (IR). The intent of this study was to characterize the acute phase response in female sheep challenged systemically with a range of doses of Escherichia coli endotoxin. Yearling ewes were challenged with an i.v. bolus dose of LPS (0, 200, 400, 600 ng/kg BW) and the acute phase response assessed by measuring serum interleukin (IL)-6 and cortisol concentrations, and the febrile response over time. A follow-up liver biopsy study was performed to determine kinetic differences in the expression of eight candidate hepatic genes between LPS dose groups using real-time RT-PCR. The initial time trail did not follow a linear dose response relationship with respect to the febrile and HPAA response to LPS challenge. Serum IL-6 concentrations increased in the two highest treatment groups but did not correlate with the observed febrile and HPAA response. The expression of Toll-like receptor 4, CD14, IL-6, tumor necrosis factor-alpha, IL-1beta, macrophage migration inhibitory factor, 11-beta-hydroxysteroid dehydrogenase (HSD), and tachykinin precursor 1 hepatic genes was dependent on both the dose and the kinetics of the response to LPS.