Biomedical subjects

A C Vos

Publications and source records attributed to A C Vos.

3 recordsLinked to original sources

PubMed2001

Effect of maternal immunity on the immune response to oral vaccination against rabies in young foxes.

OBJECTIVE: To determine effect of maternal antibodies on immune response to oral vaccination against rabies in young foxes. ANIMALS: 250 cubs from 48 vixens. PROCEDURE: Sera were obtained from cubs of 36 vaccinated (maternally vaccinated [MV+]) and 12 nonvaccinated (MV-) vixens between 23 and 71 days of age and tested for neutralizing antibodies. Seventy-one MV+ cubs and 33 MV-cubs were vaccinated orally with modified-live virus vaccine SAD B19. Geometric mean titer (GMT) was determined in these cubs approximately 21, 39, and 57 days after vaccination. In a subsequent experiment, 10 vaccinated MV+ cubs, 6 vaccinated MV- cubs, and 6 control cubs were challenge inoculated with virulent rabies virus approximately 100 days after vaccination. RESULTS: Serum GMT of nonvaccinated MV cubs (0.23 U/ml) was significantly greater than that of non-vaccinated MV- cubs (0.15 U/ml). The GMT of vaccinated MV+ cubs 21, 39, and 57 days after vaccination were 2.85, 2.11, and 0.79 U/ml, respectively, and were significantly less than those of vaccinated MV- cubs (12.19, 6.76, and 4.02 U/ml, respectively). All challenge-inoculated cubs with GMT < 0.5 U/ml succumbed to rabies. CONCLUSION AND CLINICAL RELEVANCE: Partially impaired immune response in cubs < 8 weeks old from vaccinated vixens causes insufficient protection against rabies. Inhibition of the immune response persists longer than the period during which maternal antibodies are detectable. Thus, oral vaccination campaigns for young foxes in areas where vaccination has been performed need to be reconsidered.

Administration, Oral↗

PubMed1992

Studies on the lactoperoxidase system: reaction kinetics and antibacterial activity using two methods for hydrogen peroxide generation.

Components of the lactoperoxidase system were measured during incubation in Isosensitest broth, with enzymatic (glucose oxidase, GO) or chemical (sodium carbonate peroxyhydrate, SCP) means to generate H2O2. When low levels of thiocyanate (SCN-) were used in the GO system, H2O2 was detected and lactoperoxidase (LP) was inactivated when SCN- was depleted. With 10-fold higher SCN-, LP remained active and H2O2 was not detectable. The oxidation product of the LP reaction, most likely hypothiocyanite, was present in low concentrations. When SCP was used for the immediate generation of H2O2 in a system employing low SCN-, half the LP activity was lost within minutes but thereafter it remained stable. Low concentrations of oxidation product were measured and H2O2 was not detected during the course of the experiment. At high SCN- levels, relatively high concentrations of oxidation product were produced immediately, with H2O2 undetectable. The results suggest that the final product of the LP reaction depends on the method of H2O2 generation and the relative proportions of the substrates. Antibacterial activity of the two LPS was tested against an enterotoxigenic strain of Escherichia coli. Both systems showed bactericidal activity within 4 h incubation at 37 degrees C.

Anti-Bacterial Agents↗

PubMed1992

In vitro antibacterial activity of the lactoperoxidase system towards enterotoxigenic strains of Escherichia coli.

The lactoperoxidase-thiocyanate-hydrogen peroxide (LP) system inhibited the growth of enterotoxigenic Escherichia coli strains responsible for scouring in neonatal and post-weaning piglets. An enzymatic system for hydrogen peroxide generation (glucose oxidase, GO; 0.1 U/ml) and a chemical source (sodium carbonate peroxyhydrate, SCP; 90 mg/l) were used in the LP system to test 19 strains in a 6-h growth assay at 37 degrees C. Only three strains were highly sensitive to the LP/GO system, while all exhibited significant growth inhibition with the LP/SCP system. Hydrogen peroxide alone had less effect than the complete system. The bactericidal activity of the LP/GO system towards a previously resistant strain was greatly increased by increasing the level of glucose oxidase in the system by three- or five-fold.

Animals↗