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Biomedical subjects

J P Opdebeeck

Publications and source records attributed to J P Opdebeeck.

At least 37 records · Page 2Linked to original sources
PubMed1994

Quil A and ISCOMs as adjuvants for midgut membrane antigens of Boophilus microplus.

Quil A used with Boophilus microplus gut membrane antigen (GM) had a significant effect on antibody levels induced in sheep (P < 0.05) since GM alone did not induce a significant level of antibodies. Injection of a vaccine containing GM and Quil A, either subcutaneously or intramuscularly, induced similar levels of antibodies in sheep. However, Quil A injected subcutaneously induced acute inflammatory reaction. The amount of Quil A for use with GM was determined to be 1000 micrograms/ml. Immunostimulating complexes (ISCOMs) incorporating detergent-solubilized membrane midgut antigens (TX-GM) failed to induce an immune response in cattle without the addition of Quil A. The addition of Quil A to the ISCOMs containing TX-GM did not stimulate antibody responses greater than those stimulated by TX-GM plus Quil A, and protection in vaccinated cattle was 86% and 74%, respectively.

Adjuvants, Immunologic↗
PubMed1993

An attempt to protect cats against infestation with Ctenocephalides felis felis using gut membrane antigens as a vaccine.

Cats (n = 5) were vaccinated with membrane antigens extracted from the gut of unfed fleas (Ctenocephalides felis felis) together with Quil A and RIBI as adjuvants. Five unvaccinated cats were retained as controls. All the cats were infested on 6 separate occasions with fleas (46-250 per challenge). Protection was assessed from the number of fleas retrieved and the fecundity of the female fleas, measured as the number of developed oocytes contained in the reproductive tract. Cats injected with gut membrane antigens had significantly elevated levels of anti-flea antibodies in their sera, but they were neither protected significantly against infestation with fleas nor was the apparent fecundity of fleas which had fed on vaccinated cats decreased. The possible reason why gut membrane antigens failed to protect cats against fleas are discussed.

Animals↗
PubMed1993

Immunity in vaccinated cattle exposed to experimental and natural infestations with Boophilus microplus.

Gut membranes of the cattle tick Boophilus microplus were extracted using a low ionic strength buffer and the soluble antigens were used to vaccinate Hereford cattle. Following either experimental infestation with 40,000 larval ticks or exposure to field infestation, ticks from vaccinated cattle laid 54 and 75% fewer eggs, respectively, than ticks from control cattle. After cattle were given booster injections of vaccine, and either experimentally infested with 20,000 larval ticks or exposed to field infestation, the weight of eggs laid by ticks from vaccinated cattle was reduced by 80% and 52%, respectively. Acquired immunity to the ticks varied considerably in both vaccinated and non-vaccinated cattle.

Animals↗
PubMed1992

Effects of exercise stress on various immune functions in horses.

Chemotactic locomotion and luminol-dependent chemiluminescence of neutrophils, mitogen-induced lymphocyte blastogenesis, serum cortisol concentration, immunoglobulin quantification, and leukocyte counts were determined to evaluate the effect of a single strenuous exercise in horses. Increased serum cortisol concentration (P less than 0.01) and an increased neutrophil-to-lymphocyte ratio (P less than 0.05) indicated that horses had been stressed. The chemotactic index and peak chemiluminescence production decreased significantly (P less than 0.05 and P less than 0.01, respectively) 1 day after exercise. Mitogen-induced blastogenesis of lymphocytes and serum immunoglobulin values remained unchanged in response to exercise. Results of this study indicated that a single bout of exercise may transiently impair neutrophil antimicrobial functions and nonspecific defense mechanisms, but not specific immunity in horses.

Animals↗
PubMed1991

Immune responses of cattle to biochemically modified antigens from the midgut of the cattle tick, Boophilus microplus.

Treatment of membrane antigens of the midgut (GM) of the cattle tick, Boophilus microplus with sodium metaperiodate (periodate), pronase and lipase significantly inhibited the reactivity of the GM with antibodies in the sera of 57 cattle vaccinated with GM. Treatment of GM with periodate only removed the correlation between antibody reactivity of sera and protection against infestation with ticks. A monoclonal antibody (MoAb QU13), which recognises protective antigens solubilized from GM (Lee + Opdebeeck 1991), did not react with GM treated with periodate. Cattle vaccinated with GM extracts were significantly protected against infestation with cattle ticks (P less than 0.05), whereas cattle vaccinated with either GM extracts treated with periodate or with antigens precipitated from GM extracts with MoAb QU13 and also treated with periodate, were not protected against infestation. These studies provide preliminary evidence that protective antigens in the tick midgut membrane either are carbohydrate or are dependent on carbohydrate for their specificity.

Animals↗
PubMed1991

Isolation of protective antigens from the gut of Boophilus microplus using monoclonal antibodies.

Monoclonal antibodies (mAb) were produced against midgut membrane (GM) antigens of Boophilus microplus. The isotypes of these mAb were established and their specificity characterized using double diffusion and Western blotting. GM antigens solubilized by Triton X-100 were precipitated by mAb QU13, and the precipitate was then injected into cattle to test for the presence of protective antigens. Vaccinated cattle challenged with 10-day-old larval ticks showed evidence of protection with a 62% reduction in eggs produced by ticks from vaccinated cattle compared to tick eggs from control cattle. In a second vaccine-challenge experiment, the dose of precipitate was increased and greater than 99% protection was provided to these vaccinated cattle following challenge (calculated from tick egg weights compared to the control group). The solubilized antigen(s) precipitated by QU13 were subjected to SDS-PAGE separation and the calculated sizes of these molecules were greater than 200,000, 80,000, 74,000, 62,000 57,000 and less than 30,000 MW.

Animals↗
PubMed1990

The expression of bovine lymphocyte antigen and response of Hereford cattle to vaccination against Boophilus microplus.

The influence of the bovine lymphocyte antigen MB5 on the immune response of Hereford cattle to antigens of the tick (Boophilus microplus) was examined. Groups of cattle having or lacking the antigen MB5 (MB5+ and MB5-, respectively) were vaccinated with either soluble extracts of the gut membrane of adult ticks and adjuvant or injected with adjuvant alone. Cattle vaccinated with soluble gut membrane were significantly protected from two challenges with ticks. Protection against ticks was not significantly affected by the presence or absence of the lymphocyte antigen MB5. Similarly, no differences occurred in antibody levels (measured by enzyme-linked immunosorbent assay) and cellular responses (measured by lymphocyte blastogenesis assay) in MB5+ and MB5- groups to gut antigen.

Animals↗
PubMed1990

Immune responses of infected and vaccinated Hereford cattle to antigens of the cattle tick, Boophilus microplus.

Responses of infested and vaccinated Hereford cattle to Boophilus microplus antigens were measured by enzyme-linked immunosorbent assay (ELISA), lymphocyte blastogenesis assay (LBA) and intradermal skin tests. Responses against soluble salivary gland extracts (SGS), salivary gland membrane (SGM), soluble gut extracts (GS), gut membrane (GM), soluble larval extracts (LS) and larval membrane (LM) antigens were tested. In one experiment, cattle infested with up to 160,000 ticks had positive cellular responses to SGS and significant antibodies against LM, GM, SGM, and SGS. Cellular responses to Concanavalin A were not depressed following infestation. Cattle vaccinated with GM, using Quil A as adjuvant, had positive cellular responses to gut and salivary gland antigens and significant antibody responses to all antigens tested. The antibody levels of vaccinated cattle were significantly higher than the antibody levels of infested cattle (P less than 0.05). In a second experiment, immune responses of cattle infested with 40,000 ticks were studied during 38 days. Cellular responses in LBA to several tick antigens were transiently elevated and significant levels of antibody were measured against LM, GM, SGM and SGS, from day 25 (P less than 0.05). Infested cattle had positive skin reactions following intradermal injection of larval and adult tick antigens (P less than 0.05).

Animals↗
PubMed1990

Larval membrane antigens protect Hereford cattle against infestation with Boophilus microplus.

Hereford cattle (Bos taurus) were immunized with antigens solubilized with Triton X-100 from larval membranes of the cattle tick (Boophilus microplus). Based on tick egg production compared to control cattle, vaccinated cattle were protected (78%) against challenge with 2 x 20,000 tick larvae. The soluble Triton X-100 extract of tick larval membranes was further purified by immunoaffinity chromatography, using immunoglobulin ligands (IgG1 and IgG2) from three immune steers, previously vaccinated with membrane antigens from the midgut of partly engorged adult female ticks. Cattle vaccinated with these purified antigens were protected in two separate experiments (80 and 89% respectively), against challenge with 2 x 20,000 larval ticks compared to control cattle. Whole larval membranes used as vaccines in cattle reduced the amount of eggs produced from ticks by 47% compared to control cattle, but this difference was not significant.

Animals↗
PubMed1990

Humoral immune responses of Hereford cattle vaccinated with midgut antigens of the cattle tick, Boophilus microplus.

Vaccination of cattle with midgut membrane (GM) antigen derived from the cattle tick, Boophilus microplus, infected with the adjuvant Quil A, resulted in significant increases in total immunoglobulins, mainly in the IgG1 and IgG2 fractions of the serum. Analysis of the anti-GM antibody levels of vaccinated cattle showed that the levels of IgG, IgG1 and complement-fixing antibodies were significantly correlated to protection against infestation with cattle ticks. Anti-GM antibodies of the IgG2 and IgM isotype were not correlated to protection against infestation with cattle ticks. Anti-GM antibodies fixed complement (C') in the presence of GM, larval membrane antigen and live, midgut cells, but not in the presence of live, larval cells. Anti-GM antibodies were able to fix C' equally well in the presence of GM antigen and live, midgut cells. None of the antigens tested activated the alternate pathway of complement under the conditions tested. Levels of anti-GM IgG1 antibodies were used to develop a regression model for predicting levels of protection against infestation with cattle ticks in vaccinated cattle.

Animals↗
PubMed1989

Protective efficacy of antigens solubilized from gut membranes of the cattle tick, Boophilus microplus.

Triton X-100, SDS, n-octyl glucoside, and conditions of alkaline pH and high and low ionic strength, were used to solubilize membranes prepared from the mid-gut of the cattle tick Boophilus microplus. Hereford cattle (Bos taurus) were immunized with soluble membrane antigens in saponin, and then challenged twice with 20,000 tick larvae, 7 days apart. All soluble extracts, except that extracted with high ionic strength buffer, provided significant protection (56-78%) (P < 0.05) to immunized cattle compared with control cattle. Precipitation of the soluble n-octyl glucoside extract did not alter the immunogenicity of this vaccine. Where poor responses to membrane vaccines were obtained (< 60% protection), booster injections of antigen effected increased protection. The experimental cattle were typed for bovine major histocompatibility system class 1 antigens. The presence of three antigens (MB5, MB14 and MB20) had a significant effect on protective immunity induced by the membrane vaccines (P < 0.05). Protein profiles of Triton X-100, n-octyl glucoside and low ionic strength buffer extracts were compared by high-performance size-exclusion chromatography. Tick membranes extracted by either non-ionic detergents or low ionic strength solutions provided the best source of protective antigens.

Animals↗
PubMed1989

Hereford cattle protected against Boophilus microplus with antigens purified by immunoaffinity chromatography from larval and adult ticks.

Tick larvae (Boophilus microplus) were extracted, fractionated by gel filtration and ion-exchange chromatography, and the fractions assayed by enzyme-linked immunosorbent assay (ELISA) against sera from cattle immunized and protected by antigens from the mid-gut of adult ticks. Unfractionated, whole larval extracts and selected reactive components were used to vaccinate cattle; they decreased the number of ticks dropped after challenge, but the effect of treatment was not significant. Antigens purified from crude larval extracts by affinity chromatography, using immunoglobulin ligands from an immune steer vaccinated with tick mid-gut antigens, also failed to protect cattle. However, tick extracts from both larval and adult ticks, which were first separated into membrane-associated and soluble fractions and then purified by exposure to the affinity ligands, protected cattle greater than 80% against subsequent challenge with ticks.

Animals↗
PubMed1989

The effect of antigen concentration and vaccine regimen on the immunity induced by membrane antigens from the midgut of Boophilus microplus.

Sheep and cattle were immunized with membrane antigens extracted from the midgut (GM) of the cattle tick Boophilus microplus, and antibody levels were measured by enzyme-linked immunosorbent assay (ELISA). One microgram of GM induced an antibody response in sheep comparable to that induced by 500 micrograms GM. Single or divided doses of 500 micrograms GM induced the same antibody levels in sheep over 12 weeks. Cattle vaccinated with either 500 micrograms GM in two doses or with 50 or 500 micrograms GM in three doses had significant antibody responses (P less than 0.05) and were equally protected (89%, 80% and 95%, respectively, calculated from tick egg weights) against challenge with 40,000 ticks, compared to control cattle. In another experiment, cattle vaccinated with 2.95 mg GM divided into 12 doses over 6 months had antibody levels that reached a plateau after 1.2 mg GM were administered, and were significantly protected (96%) against challenge.

Animals↗
PubMed1988

Adhesion of Staphylococcus aureus and Escherichia coli to bovine udder epithelial cells.

An assay for the adhesion of tritiated thymidine-labelled Staphylococcus aureus and Escherichia coli to bovine mammary ductular epithelial cell lines was developed. The relative adhesion of 15 strains of S. aureus to these cell lines was examined. Four strains did not adhere and the remaining 11 adhered at variable levels. Adhesion to different cell lines was generally similar. Adhesion to freshly collected bovine mammary epithelial cells was significantly greater than that to cells maintained in tissue culture. The system described was demonstrated to be a suitable model for studying adhesion of mastitis-causing organisms to bovine mammary epithelial cells.

Animals↗
PubMed1988

Hereford cattle immunized and protected against Boophilus microplus with soluble and membrane-associated antigens from the midgut of ticks.

Hereford cattle were immunized with membranes and soluble components extracted from the midgut of Boophilus microplus. Membrane vaccines protected cattle (91%) against challenge with 3 x 20,000 larval ticks administered at intervals of 7 days. Vaccines made from soluble antigens did not protect cattle. Antibody levels measured by enzyme-linked immunosorbent assay (ELISA) related to the levels of protection induced by vaccination.

Animals↗