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1.
Protein A was identified in cell wall-bound and secreted forms from Staphylococcus intermedius isolated from canine skin. A direct binding radioimmunoassay for the detection of bacterial surface Fc receptors identified 48 of 50 S intermedius isolates that contained cell wall-bound protein A. Using a competitive binding radioimmunoassay for the detection of Fc-reactive proteins in bacterial culture supernatants, we identified 9 of 50 clinical isolates of S intermedius that secreted measurable quantities of an Fc receptor into the culture medium. Concentrated culture supernatants from these isolates were analyzed by western blotting techniques and probed with either a radiolabeled human IgG Fc-specific probe or a radiolabeled affinity-purified chicken antibody against protein A. The studies reported here confirmed that Fc receptors are secreted by S intermedius isolates from dogs and are antigenically and functionally similar or are identical to staphylococcal protein A. Analysis of Fc receptor secretion by S intermedius strains, isolated from dogs with a variety of dermatologic conditions, suggested a trend between severity of skin disease and the extent of Fc receptor secretion.  相似文献   

2.
经硫酸铵盐析、DEAE 32-纤维素和Sephadex G 200柱色谱法分离得到纯化的鸡血清IgG。然后用木瓜蛋白酶水解IgG,再经DEAE 32-纤维素柱色谱纯化制得IgG Fc片段,并以IgG Fc片段免疫豚鼠制备豚鼠抗鸡IgG Fc血清。  相似文献   

3.
Receptors for the Fc regions of immunoglobin G (IgG) play a critical role in immunoregulation and immune defenses against pathogens. In this study, we describe the cloning, eukaryotic expression and IgG subclass specificity of ovine Fc gamma receptor III (FcγRIII). The newly cloned ovine FcγRIII cDNA contains a 940 bp open-reading frame (ORF), and is predicted to encode a 250 amino acid transmembrane glycoprotein composed of two immunoglobulin-like extracellular domains, a transmembrane region and a short cytoplasmic tail. The overall identity of the ovine FcγRIII amino acid sequence to its cattle, pig and human counterparts was 83.2%, 62.0%, 60.7%, respectively. Overlapping PCR was performed with the extracellular domain of ovine FcγRIII and the transmembrane and intracellular region of ovine Fc gamma chain to construct a chimeric receptor. Rosetting analysis showed that transfected COS-7 cells required Fc receptor gamma chain for the expression of FcγRIII on the surface. COS-7 cells expressing FcγRIII were able to bind chicken erythrocytes sensitized with ovine IgG1, but not IgG2. Identification of ovine FcγRIII will further our understanding of the ovine immune system.  相似文献   

4.
Several properties of the adhesins of eight isolates of Moraxella bovis recovered from cattle suffering from infectious keratoconjunctivitis, were studied. Adhesions were detected through autoagglutination in saline and hemagglutination. Autoagglutinating strains agglutinated red blood cells of the chicken, rabbit, sheep and swine, but not those of the guinea pig. The adhesins were not inhibited by D-mannose or D-galactose and resisted heating at 100 degrees C for 15 minutes. Magnesium chloride at a final concentration of 10% inhibited autoagglutination and hemagglutination. The value of the hemagglutination test for monitoring synthesis of fimbriae by M. bovis, is discussed.  相似文献   

5.
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6.
Mycoplasma synoviae was isolated from the tracheas of seven clinically normal pheasants found in the vicinity of a chicken farm infected with M synoviae, but not from 120 pheasants and partridges with respiratory disease. When specimens were examined by the polymerase chain reaction only two additional pheasants infected with M synoviae were identified, one healthy and one diseased.  相似文献   

7.
为获得J亚群禽白血病病毒(ALV-J)SU和兔IgG Fc的融合蛋白,采用PCR方法扩增出SUJ-IgG Fc基因,并克隆至pFastBac1质粒,构建转移载体pFastBac1-SUJ-IgG Fc;再将其转化DH10BacTM感受态细胞,获得重组杆状病毒穿梭质粒rBacmid-SUJ-IgG Fc;最后转染Sf9细胞,获得重组病毒rBac-SUJ-IgG Fc。免疫荧光试验结果显示,重组杆状病毒表达的融合蛋白可被ALV-J单抗JE9以及羊抗兔IgG所识别。Western blot结果显示:表达的融合蛋白与ALV-J单抗JE9以及羊抗兔IgG都有很好的反应性,其分子量大小约为95 ku。该融合蛋白的表达为鸡细胞表面ALV-J受体的研究提供了有力工具。  相似文献   

8.
An ELISA utilising a urease-antibody conjugate specific to chicken IgG was examined as an alternative to the serum agglutination and the haemagglutination inhibition tests in the diagnosis of Mycoplasma gallisepticum and M. synoviae infections in poultry. Use of a urease conjugate allowed the serum reactions to be appraised without the need for expensive photometric equipment. Non-specific binding of conjugate to antigen was eliminated by treatment of antigen coated microplates with 10% foetal calf serum in phosphate buffered saline. Some chicken serums produced non-specific reactions. These reactions were reduced without any loss of test sensitivity by making the initial 1:5 dilution of chicken serum in whole sheep serum rather than diluting buffer. Tests on serums from experimentally infected chickens showed that the urease ELISA was specific, and was as sensitive as the serum agglutination test but more sensitive than the haemagglutination inhibition test.  相似文献   

9.
Short nucleotides directly labelled to alkaline phosphatase (SNAP probes) are an interesting alternative to digoxigenin-labelled probes (DIG probes), because they reduce the number of steps necessary in dot blots for the detection of DNA or amplificate. This study examined the questions whether a SNAP probe might not only save time, but also increase the sensitivity of another PCR-based DNA probe test using a digoxigenin probe. Amplificates obtained by multispecies polymerase chain reaction (PCR), with either purified genomic DNA or DNA extracted from tracheal swabs taken in chicken flocks, were detected by both methods. The results for the clinical specimens were compared to culture. Under stringent conditions, the specificity and sensitivity obtained with the SNAP probe were comparable to the results obtained with the DIG probe. The quantities 10 fg (SNAP probe) and 100 fg (DIG probe) of purified Mycoplasma synoviae DNA were detected after amplification, but more positive clinical specimens were detected with the DIG probe. Under non-stringent conditions sensitivity with purified DNA did no change, but the coloration of the dots improved markedly, and more positive specimens could be detected with the SNAP probe than with the DIG probe, truly positives as confirmed by culture. Because cross-reaction with Mycoplasma gallisepticum and Mycoplasma imitans, two species with DNA that was also recognized by the multispecies primers, occurred under non-stringent conditions, it was concluded that, to take the full advantage of SNAP probes, their use in combination with species-specific primer pairs is recommended. PCR as a method for mycoplasma detection is however, always accompanied with serological and cultural methods. When a M. synoviae mono-infection is likely by serological results, non-stringent dot blot conditions and use of the SNAP probe will ease and improve the detection of mycoplasma.  相似文献   

10.
The mean flock size was ten chickens per rural farmer. Antibodies to Mycoplasma gallisepticum and Mycoplasma synoviae were detected in 57.88% and 67.33% of the chicken sera respectively.  相似文献   

11.
125-I-IgG binding activities were observed with 15 (17%) of 90 S. intermedius isolates from dogs and 39 (95%) of 41 S. hyicus isolates from pigs. Binding activities were not detected with S. hyicus isolates from cows. The IgG binding proteins of 2 S. intermedius, 2 S. hyicus, and protein A from S. aureus Cowan I were isolated from their cell surfaces. The proteins precipitated with IgG preparations from human, rabbit, pig, dog and horse, but not with IgG from cow, mouse and chicken. This indicated that these IgG binding proteins could be classified as type I receptors. In addition, the isolated proteins from all 3 staphylococcal species precipitated with polyclonal chicken anti-protein A antiserum. SDS-PAGE, Western blotting and gel isoelectric focussing of the proteins revealed numerous bands in the 42,000 D range and acid isoelectric points. The isoelectric point of the isolated proteins from both S. intermedius cultures was slightly more acidic than those from S. hyicus and S. aureus. The present results indicate a close functional and antigenic similarity, if not identity, between IgG binding proteins of S. intermedius and S. hyicus, and protein A of S. aureus.  相似文献   

12.
Mycoplasma synoviae is a major pathogen of chickens and turkeys, causing respiratory disease and infectious synovitis. M. synoviae haemagglutinin VlhA is an abundant surface-exposed lipoprotein and immunodominant antigen. Post-translational cleavage of VlhA generates two proteins, MSPB and MSPA. MSPB, the amino-terminal end of VlhA, is a lipoprotein of about 40-50 kDa but can appear in truncated forms (tMSPB) of about 20-30 kDa. The aim of this study was to determine whether MSPB and tMSPB can stimulate chicken macrophages to secrete NO and cytokines. Macrophages derived from chicken monocytes (MDM) or the MQ-NCSU macrophage cell line were stimulated with M. synoviae protein extracts containing MSPB or tMSPB, as well as with purified MSPB and tMSPB. Proteins from detergent extractions induced IL-6 secretion in MDM and NO secretion in MQ-NCSU. Both MSPB and tMSPB were capable of inducing NO secretion in MQ-NCSU, as well as IL-6 and IL-1beta in MDM. The activity of IL-6 induced by purified tMSPB was similar to the effect of 60 pg/ml of recombinant chicken IL-6. The effect of IL-1beta induced by tMSPB was comparable to the effect of 10 ng/ml of recombinant IL-1beta. Whereas all samples containing MSPB were able to induce NO, IL-6 and IL-1beta, it seemed that the purified tMSPB of about 20 kDa was the most potent in its ability to induce IL-6 and IL-1beta in MDM. Compared to MSPB, tMSPB lacks about 200 amino acids in its carboxyl-terminal part. Therefore, our results suggest that the major part of the stimulating activity is associated with the amino-terminal part of MSPB, most likely with its lipid moiety.  相似文献   

13.
The comparative thermostability of 4 duck hepatitis (DH) viruses were tested at various temperatures for different times. Titer of duckling-passaged, pathogenic DH virus decreased from 10(4.50) to 10(2.33) and 10(2.20) median infective doses (ID50/0.1 ml, respectively, in 2 tests; titer of chicken embryo-passaged, nonpathogenic, but embryo-lethal, DH virus decreased from 10(6.00) to 10(0.46) and from 10(6.62) to 10(0.63) ID50/0.1 ml, respectively; duck embryo fibroblast culture-passaged and duck embryo liver cell culture-passaged, chicken ebryo-infective, but nonlethal, DH viruses were completely inactivated or nearly so after being kept at 56 C for 30 minutes. Duckling-passaged DH virus was not detected on day 21, whereas 10(0.62) ID50 of chicken embryo-passaged DH virus per 0.1 ml remained on day 32 when being kept at 37 C. Titer of chicken embryo-passaged DH virus decreased from 10(7.00) to 10(1.16) ID50/0.1 ml after being kept at room at room temperature for 150 days, to 10(5.17) ID50/0.1 ml after being kept at 4 C for 70 weeks, to 10(6.17) ID50/0.1 ml after being kept at -20 C for 70 weeks, and to 10(6.38) ID50/0.1 ml after being kept at -60 C for 1 year.  相似文献   

14.
In a preceding report we have shown that the lectin Helix pomatia A hemagglutinin (HP) binds to two subpopulations of neuraminidase-treated equine peripheral blood lymphocytes (PBL), constituting about 20% and 75% of PBL, respectively. The aim of the present study was to further characterize these HP+ cells in regard to other surface markers such as receptors for guinea pig erythrocytes (GPR+ cells), membrane-bound immunoglobulins (sIg+ cells), receptors for activated complement (C3R+ cells) and receptors for IgG (Fc alpha R+ cells). This was done by double marker analysis and by lymphocyte fractionation either on columns charged with HP coupled to Sepharose beads or by rosetting with guinea pig erythrocytes. The fractions were also analysed for their proliferative response in the mixed lymphocyte tumor cell interaction (MLTC) assay and to the mitogens leucoagglutinin (La) and concanavalin A (Con A). The results revealed that the majority of GPR+ cells also expressed high avidity receptors for HP, as defined by means of direct immunofluorescence. These cells constituted a subpopulation of GPR+/HP+ cells T cells comprising approximately 20% of PBL. In contrast, about 75% of the HP+ cells in indirect immunofluorescence were GPR-. The fractionation experiments showed that HP+ and GPR+ cells were probably not B cells since they were sIg-. The C3R+ and Fc alpha R+ lymphocytes were heterogeneous in regard to HP receptors but the majority of these cells was also found in the fractions depleted of HP+ and GPR+ lymphocytes. The fractions eluted from HP columns gave a strong proliferative response in MLTC, whereas fractions depleted of HP+ cells responded poorly. However, in contrast to the GPR+-depleted fractions, those enriched in GPR+ lymphocytes responded poorly to the T cell mitogens La and Con A. The mitogenic response of the HP-column fractions to La and to Con A was variable. The results are discussed in relation to HP being a surface marker for a heterogeneous population of equine T cells.  相似文献   

15.
AGPT and HA tests were employed for rapid diagnosis of PPRV infection in sheep and goats in Sudan. Forty lymph nodes and spleen samples from suspected cases of PPR in both sheep and goats were examined by AGPT and HA tests for detection of PPRV antigen. Viral antigen was detected from (77.5%) of the samples tested by AGPT and (92.5%) tested by HA test. The results of both tests revealed that HA test was more sensitive than AGPT for detection of PPRV antigen (Kappa statistics 0.4366). Another advantage of the HA test over AGPT was that it can differentiate PPRV from RPV. Thus the HA test represents a quick, easy, simple, cheap and reliable confirmatory test for the diagnosis of PPR and differential diagnosis of PPRV and RPV. The HA test was carried out using chicken, goat and pig RBCs. Chicken RBCs were found to be the most sensitive for detection of PPRV antigen, followed by goat then pig RBCs. The HA time when using chicken RBCs was 20–25 minutes, using goat RBCs was 25–30 minutes and using pig RBCs was 40–45 minutes. The distribution of PPR infection in four different regions of Sudan was investigated.  相似文献   

16.
We studied the influence of Imipenem and Cefmetazol (50 mg/l) on lymphocyte receptors CD2, Fc and C3b of complement. The lymphocytes were obtained from human blood and mice axillary ganglions. Cefmetazol significantly increases the binding capacity of human lymphocyte receptors CD2 to sheep red blood cells while Imipenem does not alter this binding. The number of Fc lymphocyte receptors for the constant fraction of IgG is found to be significantly increased when the lymphocytes are incubated in vitro with Imipenem and Cefmetazol. When the lymphocytes are treated with these antibiotics there is an increase in the receptors capable of binding to fraction C3b of the complement.  相似文献   

17.
One hundred and twenty bacterial strains were tested for non-immune binding of radiolabelled bovine, ovine, caprine and equine immunoglobulins. Bacteria possessing previously defined IgG receptors interacted in a well defined manner with purified IgG subclass immunoglobulins. Human group C and G streptococci carrying IgG receptors type III were capable of binding all IgG subclasses in the four mammalian species studied. Protein A-containing staphylococci demonstrated a restricted specificity with binding of bovine IgG1, ovine IgG1, caprine IgG1 and IgG2 as well as equine IgG(ab). Group A streptococci which can bind human IgG did not show specific reactivity. A new type of binding unrelated to the regular Fc-mediated binding was observed with equine IgG(T).The differences in specificity for IgG subclasses suggest that structures with binding capacity to streptococcal type III Fc receptors are different from staphylococcal protein A reactive sites. Inhibition experiments performed with purified immunoglobulins showed that individual IgG subclasses differed greatly in their inhibiting capacity reflecting differences in avidity.The high avidity and the broad, unrestricted immunoglobulin G reactivity of streptococcal IgG receptor type III indicate that human group C and G streptococci may provide a valuable tool for solid phase absorption of immunoglobulins from several mammalian species.  相似文献   

18.
Hemolytic disease of the newborn does not develop in rhesus monkeys because placentally-transferred maternal antibodies do not induce immune clearance of the newborn's erythrocytes. In an in vitro RBC adherence assay, rhesus peripheral blood monocytes did not bind newborn's RBC which had been coated in utero or in vitro with maternal antibodies. Nevertheless, rhesus phagocytes possess receptors that are specific for the Fc portion of IgC and for the C3b. Using purified human IgG subclasses as inhibitors of RBC adherence, rhesus Fc receptors preferentially bind IgG1 and IgG3. Thus, it may be that maternal antibodies are non-opsonic because they belong to IgG subclasses that do not bind effectively to rhesus Fc receptors. Also, RBC adherence appears to be controlled by the level of antibody coating which in turn is determined by avidity of the antibodies and by the number of RBC membrane determinants. The failure of maternal antibodies to opsonize the newborn's RBC and thus cause hemolytic disease is very likely due to the low avidity of antibodies and to the weak expression of blood group determinants on the membranes of these RBC.  相似文献   

19.

Background

Heat‐treatment of colostrum is a method developed to reduce calf exposure to pathogens. Infrared (IR) spectroscopy and Brix refractometers can be used for measuring colostral IgG concentration and assessing colostrum quality.

Objectives

To determine the impact of heat‐treatment on accuracy of IR spectroscopy and Brix refractometers for measuring colostral IgG concentration and assessing colostrum quality before and after heat‐treatment.

Animals

A total of 60 Holstein dairy cows on 8 commercial dairy farms.

Methods

A cross‐sectional study was designed to determine the effect of heat‐treatment at 60°C and 63°C each for 30 and 60 minutes duration on colostral IgG concentration measured by the reference radial immunodiffusion (RID) assay, IR spectroscopy, and digital and optical refractometers.

Results

Colostrum IgG concentration significantly decreased after heat‐treatment at 63°C for 30 or 60 minutes as measured by RID, but the IgG values remained unchanged when measured by IR spectroscopy and refractometers. The lowest correlation coefficient found between IR spectroscopy (r = 0.70) and RID results was in colostrum heat‐treated at 63°C for 60 minutes. For digital (r = 0.48) and optical (r = 0.50) refractometers, the lowest correlation coefficient was at 63°C for 30 minutes when compared to RID. The accuracy of the IR spectroscopy, digital and optical Brix refractometers was decreased from 91.7 to 80%, 81.7 to 45%, and 80 to 45%, respectively, when colostrum heat‐treated at 63°C for 60 minutes.

Conclusions and Clinical Importance

Radial immunodiffusion, IR spectroscopy, and Brix refractometers exhibit utility for measuring IgG concentration when colostrum heat‐treated at 60°C but does not detect decrease IgG concentrations when heat‐treated at 63°C.  相似文献   

20.
The immunoglobulin (Ig) G binding properties of protein A made affinity chromatography with protein A an acceptable method for isolation of IgG in mammals. Rabbit IgG was isolated by fractionation of serum on a column containing protein A coupled to Sepharose. The IgG molecules of subclasses 1, 2, and 4 and their fragments containing the Fc region had this affinity, but not IgG-3. The second peak, after washing with 1M acetic acid eluate (pH 7.0) as shown in the Ouchterlony agar immunodiffusion test, was the IgG fraction. Similar studies on normal and hyperimmune chicken sera indicated that chicken IgG does not bind to protein A molecules. Further studies indicated that chicken plasminogen did not bind covalently to protein A molecules and subsequently did not interfere in the affinity of protein A to bind to IgG molecules. The inhibition of binding of chicken IgG to protein A molecule is still unknown.  相似文献   

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