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J P Opdebeeck

Publications and source records attributed to J P Opdebeeck.

48 records · Page 3Linked to original sources
PubMed1988

Determination by enzyme-linked immunosorbent assay of the optimal dose of staphylococcal leukocidin for systemic immunization of dairy cows.

A dose-response study was conducted to determine the optimal dose of staphylococcal leukocidin toxin to use for systemic vaccination of lactating dairy cows. Each of 5 groups of cows (8 cows/group) were given 2 injections of crude leukocidin (dose range, 9 to 2,700 mg). Antileukocidin antibody concentration in milk samples collected before vaccination and at 4 and 10 weeks after vaccination was determined by use of an ELISA. The highest antibody concentration at postvaccination sample collection dates was observed in cows of the group immunized with 900 mg of leukocidin. This appeared to be the optimal vaccination dose for production of antileukocidin antibodies in the mammary gland of lactating cows.

Animals↗
PubMed1988

Vaccines to protect Hereford cattle against the cattle tick, Boophilus microplus.

Vaccines made from gut and gut and synganglion tissue dissected from Boophilus microplus gave 87% and 80% protection, respectively, compared with adjuvant-injected controls in cattle against three infestations with 20,000 larval ticks administered over 14 days. A vaccine prepared from synganglion alone did not protect cattle. Ticks collected from vaccinated cattle produced 95% and 91% fewer eggs, respectively, than ticks from control animals. Vaccinated cattle were protected (36%) 7 months after they had been immunized with tick antigens. Antibody responses to the vaccines were detected by enzyme-linked immunosorbent assay (ELISA).

Animals↗
PubMed1987

The expression of capsule in serum-soft agar by Staphylococcus aureus isolated from bovine mastitis.

Strains of Staphylococcus aureus were isolated from bovine mastitis, subcultured and maintained in the laboratory for up to 3 years. Encapsulation was assessed by production of a diffuse colony in serum-soft agar. Eight (4%) of 200 strains were encapsulated. Three rapid passages of the remaining 192 strains through either brain-heart infusion broth containing 30% serum or modified 110 medium retrieved the capsule in 75%, but this was rapidly lost after subculture on blood agar. The stimulation of capsule production was studied in 18 of these strains by addition of various components to the passaging medium. Heat-labile factors in serum, milk and mastitic milk enhanced capsule production while bovine serum albumin, an extract of polymorphonuclear leucocytes, NaCl and immunoglobulins had minimal effect. The results indicate that encapsulation is common in bovine staphylococci and while it is lost on subculture, may be retrieved under appropriate conditions.

Animals↗
PubMed1985

The expression of capsule in serum-soft agar by Staphylococcus aureus isolated from human clinical sources.

Staphylococcus aureus isolates from human clinical sources were incubated for various times in modified 110 medium and tested for production of capsule by the serum-soft agar technique. Ten (5.7%) of 175 isolates were encapsulated after incubation for 24 h. A more detailed examination of 77 isolates showed that incubation period affected the production of capsule. After 2 h, 31% were encapsulated, but after 6 h and 24 h this decreased to 17% and 4% respectively. Rapid passage in vitro induced the expression of capsule in four of 50 unencapsulated strains. Only three of 20 encapsulated strains could be typed with standard antisera.

Agar↗
PubMed1985

Immunogenic properties of Staphylococcus aureus and Streptococcus agalactiae administered separately and in combination to lactating cows.

Composite bacterins of Staphylococcus aureus and Streptococcus agalactiae, or either bacterin alone, were administered systemically to groups of lactating cows. The response to each bacterin was unaffected by the simultaneous administration of the antigens when assessed by comparing the antibody levels in milk by enzyme-linked immunosorbent assay. There was no evidence of cross reactivity of the antigens studied, nor immunopotentiation by either bacteria.

Animals↗
PubMed1985

Antibodies in bovine serum and lacteal secretions to capsular antigens of Staphylococcus aureus.

Pregnant cows were immunized systemically with an encapsulated strain of Staphylococcus aureus (Smith diffuse strain). Antibodies in serum and colostrum were detectable by enzyme-linked immunosorbent assay and prevented capsule production by the Smith diffuse strain in a soft agar medium. Antibody in milk, although detectable by enzyme-linked immunosorbent assay, did not affect the production of capsule in vitro. Antibodies were absorbed from milk and serum, using staphylococcal surface antigen. In a 2nd experiment, lactating cows were immunized, using Smith diffuse strain antigens in the form of a bacterin or as a surface extract; the bacterin or extract was emulsified in Freund's incomplete adjuvant. Antibody titers in the milk of cows given bacterin were significantly (P less than 0.001) greater than titers in the milk of animals immunized with surface extract. The soft agar technique was insufficiently sensitive to detect antibody in the milk of any of the cattle.

Animals↗
PubMed1984

Comparative effect of selected adjuvants on the response in the bovine mammary gland to staphylococcal and streptococcal antigens.

The effect of 4 adjuvants on the response in the lactating bovine mammary gland to an antigenic stimulus was examined. Fifty four lactating Holstein Friesian cows were randomly allocated to 6 groups. Four of these groups received a staphylococcal and streptococcal bacterin-toxoid vaccine administered systemically in association with an adjuvant preparation. The adjuvants used were: aluminum hydroxide gel, Freund's incomplete adjuvant, a metabolizable lipid emulsion and Bordetella pertussis. Two further groups serving as controls received saline, or the vaccine suspended in saline only. The immunoglobulin G response specific for each of 3 vaccine antigens, was monitored in the milk by means of enzyme-linked immunosorbent assay for a period of 23 weeks. The results indicated that high levels of antibody may be maintained in the milk, throughout the average lactation, if cows are vaccinated in the region of the supramammary lymph node with an optimum dose of antigen emulsified in Freund's incomplete adjuvant.

Adjuvants, Immunologic↗
PubMed1983

Encapsulation of Staphylococcus aureus isolated from bovine milk.

Evidence is presented that nearly all Staphylococcus aureus infections of the bovine mammary gland are by encapsulated organisms (94% of isolates examined). This observation is based on the demonstration of diffuse growth in serum-soft agar, of cultures taken directly from mastitic milk without subculture on artificial media. Only milks containing pure cultures of S. aureus were examined. It was previously reported that only 6% had capsules. Evidence is presented that as few as 3 or 4 subcultures and/or a short storage on artificial media results in loss of encapsulation of most S. aureus of bovine origin. Antisera raised against encapsulate strains inhibit the expression of capsule formation on bacteria that are encapsulated in the presence of normal serum.

Animals↗
PubMed1983

Frequency and immunologic cross-reactivity of encapsulated Staphylococcus aureus in bovine milk in New York.

A total of 213 milk samples, which were positive by bacteriologic cultural examination for Staphylococcus aureus, were obtained from lactating cows on 55 farms throughout the dairying areas of New York. The S aureus isolates were evaluated for encapsulation directly from milk by the serum-soft agar technique. Results indicated that 93% of S aureus field isolates showed evidence of encapsulation on direct evaluation from milk. Suppression of capsule formation in vitro was seen in 72.7% of isolates when grown in the presence of 1% of anticapsular sera. One of the 3 anticapsular sera used exhibited a significantly higher level of cross-reactivity with the field isolates than did the 2 other sera. Increasing the concentrations of the antisera to 2% and 4% in the serum-soft agar had no effect on the expression of capsule in those isolates which had shown no evidence of capsule suppression with the specific antisera at the 1% level. Limited subculture of randomly selected encapsulated isolates on artificial media resulted in a decrease in the percentage of encapsulation from 100 to 33.3.

Animals↗
PubMed1982

Antibody response in lacteal secretions of cows after immunization with various concentrations of staphylococcal and streptococcal antigens.

A total of 55 lactating Holstein cows were randomly allocated to 6 groups. Five of these groups (No. 2 through 6) were inoculated on 2 occasions in the region of the external inguinal lymph node with various concentrations of 3 bacterial antigens. Saline solution was administered to group 6 as a control. The antigen preparations consisted of a Staphylococcus aureus bacterin, a Streptococcus agalactiae bacterin, and staphylococcal alpha-toxoid. These antigens were administered as a composite preparation suspended in saline solution. The concentration of antibody in the lacteal secretions, represented by immunoglobulin G specific for each of the 3 vaccine antigens, was monitored during the 18-week experimental period by enzyme-linked immunosorbent assay. The concentration of each of the 3 vaccine components which was required to stimulate a maximal immune response in the lactating gland appears to have been established.

Animals↗