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Y Elazhary

Publications and source records attributed to Y Elazhary.

34 records · Page 2Linked to original sources
PubMed1993

[Bovine serum albumin inhibits the adsorption of respiratory syncytial virus on MDBK cells].

In order to obtain optimal bovine respiratory syncytial virus adsorption to host cells, the effect of several products (fetal bovine serum, bovine serum albumin, ovalbumin and cytochrome c) was studied. The adsorption of the virus to MDBK cells was higher in the presence of 2% than in the presence of 5% fetal bovine serum. Adsorption was inhibited in the presence of bovine serum albumin at concentrations > 0.2% when added before or at the same time as the virus. Ovalbumin and cytochrome c did not inhibit adsorption. These results will allow the study of virus adsorption on cell receptors.

Animals↗
PubMed1991

Non-specific immunoprecipitation of rotavirus Vp6 protein with Staphylococcus aureus.

The specificity of Staphylococcus aureus and protein A-Sepharose (PA-S) were compared in the radioimmunoprecipitation assay for the characterization of monoclonal antibodies (mAbs) against rotavirus proteins. Five mAbs directed against bovine rotavirus Q17 proteins Vp6 and Vp7 and one mAb directed against human rotavirus protein Vp4 were used in this study. mAbs directed against other viruses, NS-1 culture supernatant and ascitic fluid, were used as control reagents. A non-specific immunoprecipitation of the viral protein Vp6 was always found with S. aureus, but not with PA-S. mAb 74 reacted with rotavirus antigens in ELISA and in indirect immunofluorescence assay but did not immunoprecipitate a viral protein with PA-S. This mAb immunoprecipitated the viral protein Vp6 when S. aureus reagent was used. This false positive reaction was always present and could lead to confusing results in the analysis and characterization of mAbs against rotavirus.

Antibodies, Monoclonal↗
PubMed1991

Characterization of bovine rotavirus VP6 and VP7 as glycoproteins using monoclonal antibodies.

Bovine rotavirus proteins were analysed by a panel of monoclonal antibodies. Glycosylated epitopes were identified on both inner and outer capsid proteins (VP6 and VP7 respectively). VP7 possessed a periodate insensitive epitope which was, however, sensitive to endoglycosidase H, mixed glycosidases and to protease treatment. This epitope was not detected on viruses grown in the presence of 2-deoxy-D-glucose or tunicamycin. An epitope was detected on VP6 which was sensitive to periodate oxidation. The blotted protein reacted with a glycan assay kit; yet the epitope was not affected by endoglycosidase H and was found on viruses grown in the presence of 2-deoxy-D-glucose or tunicamycin. These results suggest that VP7 and VP6 epitopes are carbohydrate dependent. The VP7 epitope contains an N-linked carbohydrate moiety in contrast to the VP6 epitope which appears to contain O-linked glycosyl units.

Acetylglucosaminidase↗
PubMed1990

Monoclonal antibodies to Quebec strain (Q17) of bovine rotavirus.

Fourteen monoclonal antibodies (MAbs) against "Quebec" strain (Q17) of bovine rotavirus were isolated and characterized. Four were specific for viral protein Vp7 and ten were specific for viral protein Vp6. Five different isotypes were represented by this group of antibodies. All of the anti-Vp6 and none of the anti-Vp7 antibodies were sensitive to the effects of periodate on their antigen. The antibodies could be separated into three groups based on their relative resistance to the dissociation of their antigen-antibody complex by thiocyanate. The MAbs cross-reacted with the proteins of porcine and human rotaviruses both by immunoprecipitation and immunoblot analyses. These techniques revealed the differences in Mw of the viral proteins from different serotypes.

Animals↗
PubMed1990

Study of virus excretion in feces of diarrheic and asymptomatic calves infected with rotavirus.

Infection of calves by rotavirus could lead to diarrhea or subclinical disease. Therein, kinetic of viral excretion from a group of asymptomatic calves, previously exposed to a virulent strain of rotavirus, is compared to that of a group the calves of which had diarrhea associated with rotavirus infection. As determined by an enzyme-linked immunosorbent assay (ELISA), duration of rotavirus shedding in feces and maximum yield of virus antigen were similar within the two groups of calves. Rotaviruses isolated from the two above groups of animals were antigenically related as shown by neutralization tests, and showed a similar RNA electrophoretic profile. In conclusion, it is likely that both asymptomatic and diarrheic calves infected by rotavirus are equally a major source of contamination to contact healthy calves.

Animals↗
PubMed1989

Detergent solubilised bovine viral diarrhea virus elicits a similar immune response as the inactivated virus.

The immune response to two detergent solubilised preparations of Bovine Viral Diarrhea Virus (BVDV) proteins were compared with the response to a chemically inactivated BVDV preparation. The antibody titres were measured with the standard immunofluorescence assay and with a newly developed enzyme linked immunosorbent assay (ELISA). The range of viral protein specificity of the antibodies was compared using SDS-polyacrylamide gel electrophoresis (SDS-PAGE) followed by Western blot analysis. The results clearly demonstrate that the detergent solubilised viral proteins are equally as effective immunogens as the killed BVDV vaccine both in terms of antibody titers and specificity.

Animals↗
PubMed1989

Purification of IgG from serum with caprylic acid and ammonium sulphate precipitation is not superior to ammonium sulphate precipitation alone.

Immunoglobulin G (IgG) from bovine serum raised against Aeromonas Salmonicida was purified by ammonium sulphate precipitation (ASP) or caprylic acid treatment followed by ammonium sulphate precipitation (CAAS). Purity of IgG samples prepared by both methods were examined by High Performance Gel Permeation Chromatography, electrophoresis and antibody activity assay. Results suggest that IgG prepared by ASP is better than that obtained by CAAS method in terms of the yield of the IgG monomers and the recovery of the antibody activity.

Aeromonas↗
PubMed1988

High-performance liquid chromatographic separation and immunological characterization of soluble bovine viral diarrhea virus antigen.

Sodium dodecyl sulphate-polyacrylamide gel electrophoresis and Western blot analysis of the protein extracts from bovine viral diarrhea virus (BVDV, Singer strain) infected primary calf testicle cells (soluble antigen) showed the presence of four virus specific polypeptides of 105, 90, 84 and 67 kiloDaltons (kD) the 84-kD being the most abundant. Anion-exchange high-performance liquid chromatography (HPLC) of soluble antigen separated the virus specific polypeptides in individual peaks while the gel permeation HPLC collected all of them in a single protein aggregate peak of 290 kD. Except for the 84-kD polypeptide peak in anion-exchange HPLC, all peak fractions were found to be heterogeneous in nature having more than one polypeptide. Analysis of the antisera raised against the peaks having antigen activity showed that antisera against the 84-kD polypeptide peak did not neutralise BVDV while those against the fractions containing the 90- and 105-kD polypeptides neutralised the virus.

Animals↗
PubMed1988

Standardization and kinetics of in vitro bovine blood lymphocyte stimulation with bovine rotavirus.

Two groups of 3-month old calves were immunized intramuscularly with attenuated bovine rotavirus and boosted 21 and 42 days later. The first group of three calves were vaccinated with live virus emulsified with incomplete Freund's adjuvant (IFA) and the second group was immunized with live virus suspended in phosphate buffered saline (PBS). Three other calves, serving as controls, were inoculated with PBS emulsified with IFA. The specific cell-mediated and antibody responses of the animals were studied. Preliminary analysis of in vitro peripheral blood lymphocyte transformation to bovine rotavirus determined optimal conditions as: 96 h culture period, 5 X 10(5) cells per culture in RPMI 1640 medium containing 10% heat-inactivated bovine fetal serum and the use of inactivated virus in the cell culture at a concentration of 5 X 10(6) median tissue culture infective dose before inactivation. Specific blastic stimulation was observed on calves immunized with the rotavirus emulsified with IFA after the second and third vaccine inoculation with stimulation index values varying from 2.00 to 5.73. Serum neutralizing antibody titers of 1/25,600 were also induced in the same calves. Calves immunized with rotavirus-PBS suspension developed a mean antibody titer of 1/1,600, but showed no specific lymphocyte stimulation. No increase in specific immune responses was detected in the control animals.

Animals↗
PubMed1988

Influence of immunomodulatory agents on bovine humoral and cellular immune responses to parenteral inoculation with bovine rotavirus vaccines.

Sodium diethyldithiocarbamate (DTC), mycobacterium cell wall extract (MCWE, Regressin), killed Corynebacterium parvum (C. parvum, Immunoregulin) and muramyldipeptide (MDP) were each combined with purified, live bovine rotavirus and inoculated into 3 month-old Holstein-Friesian calves in order to examine their ability to potentiate specific humoral and cellular immune responses. The vaccinated calves were boosted twice at 3 and 6 weeks after initial vaccine inoculation. The rotavirus was administered intramuscularly either in an aqueous suspension or in a water-in-oil (WIO) emulsion, prepared with incomplete Freund's adjuvant (IFA). DTC and C. parvum were given by the intravenous route, while MCWE and MDP were incorporated directly in the rotavirus suspension. Two groups of calves were also vaccinated either with rotavirus and IFA or with rotavirus emulsified in mineral oil and a mannide oleate compound (MOC, Montanide 888). A control group of calves was given phosphate-buffered saline (PBS) solution emulsified with IFA. The different vaccine preparations were then compared by studying the kinetics of serum rotavirus-neutralizing antibody production and of proliferative response by blood lymphocytes following in vitro stimulation with bovine rotavirus. The results showed that: (1) the bovine rotavirus should be incorporated in a WIO emulsion in order to induce a cell-mediated immune response as detected by the rotavirus-specific in vitro stimulation test with blood lymphocytes, and to produce higher neutralizing antibody titers in the serum; (2) the vaccines prepared with the mineral oil-MOC complex or IFA both induced comparable levels of humoral and cellular immune responses. The use of mineral oil and MOC as adjuvant may be preferred to IFA, because of the facility of preparing the vaccine and of the low viscosity of the resulting WIO emulsion: (3) the addition of MDP to the WIO emulsion prepared with IFA resulted in a higher cell-mediated immune response as determined by the in vitro blood lymphocyte transformation index specific for bovine rotavirus.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1988

Immune response of pregnant heifers and cows to bovine rotavirus inoculation and passive protection to rotavirus infection in newborn calves fed colostral antibodies or colostral lymphocytes.

The efficacy of an adjuvanted bovine rotavirus vaccine in pregnant cattle (15 heifers and 2 cows) was studied. Each of 4 animals was inoculated IM at 8, 5, and 2 weeks before parturition with a water-in-oil emulsion containing live purified bovine rotavirus, mineral oil, and a mannide oleate compound. Four other animals were treated identically, except that muramyl dipeptide was added to the virus preparation. Five additional animals were inoculated orally at the same time intervals with adjuvant-free viral suspension, and 4 other pregnant animals inoculated only with buffer served as uninoculated controls. Kinetic studies of the specific immune responses were determined by quantification of the rotavirus-neutralizing antibodies and by a rotavirus lymphocyte stimulation test in vitro. Results showed that only the emulsions induced marked enhancement of rotavirus antibody titers in the serum, colostrum, and milk of inoculated cows. Colostral and milk lymphocytes isolated from these cows had a positive in vitro proliferative response to rotavirus stimulation, which lasted at least 21 days after parturition. The values of the stimulation index obtained with the colostral/milk lymphocytes were higher than those of the blood lymphocytes, reflecting increased lymphocyte activity in the colostrum/milk. However, addition of muramyl dipeptide to the emulsion preparation did not exert any potentiating effect on the immune response to rotavirus. Calves fed for the first 5 days after birth with a rotavirus-immune cell-free colostrum supplement were protected from a rotavirus challenge exposure on the third day after birth. Virus was not detectable in their feces.(ABSTRACT TRUNCATED AT 250 WORDS)

Adjuvants, Immunologic↗
PubMed1981

[Diagnosis of septic abortion in dairy cows].

During a two year period, March 1977 to April 1979, a total of 92 bovine abortions were studied. The cause of abortion was determined in 34.8% of the cases examined. Opportunistic bacteria, the most commonly diagnosed cause of abortion, accounted for 31.2% of the cases. Leptospirosis was associated with 28.1% of the abortions, infectious bovine rhinotracheitis and fungi in respectively 15.7%, bovine viral diarrhea in 6.2%. A congenital abnormality accounted for one case (3.1%). In 23 cases (25%), there was no definitive diagnosis, in spite of evidence of experience with pathogen or suggestive findings of pathology, but insufficient evidence to warrant diagnosis. No findings were recorded in 35.8% of the (possibly noninfectious) cases and in only four cases (4.4%), specimens were unsatisfactory for examination.

Abortion, Septic↗