Search Results

You are looking at 1 - 10 of 19 items for :

  • Refine by Access: All Content x
Clear All

The thymus is a primary lymphoid organ that provides a specialized microenvironment for T-cell maturation. 1 Mature T cells migrate from the thymus to secondary lymphoid organs such as the spleen, hemal nodes, and lymph nodes, 2 thereby

Full access
in American Journal of Veterinary Research

enterica serotype Typhimurium was used and was > 99% pure. g Splenocytes Immediately following euthanasia, an approximately 5-cm 3 portion of fresh spleen was harvested from each of the 8 dogs. The spleen was stored in PBS solution on ice for

Full access
in American Journal of Veterinary Research

SUMMARY

A study was conducted to determine the effect of monophosphoryl lipid A (mpl) and trehalose dimycolate (tdm) as adjuvants on the protective responses in balb/c mice vaccinated with Brucella abortus salt-extractable protein (bcsp) or proteinase-K-treated B abortus lipopolysaccharide (pklps). Mice were vaccinated with different doses of bcsp or pklps given alone or in combination with mpl or tdm. Mice were challenge-exposed 4 weeks later with virulent B abortus strain 2308. Two weeks after challenge exposure, the number of B abortus colony-forming units (cfu) per spleen, spleen weights, and spleen cell interleukin 1 production were measured. Serum IgG and IgM concentrations specific for vaccinal immunogens were measured before and after challenge exposure with B abortus.

Spleen weights and mean B abortus cfu per vaccine group were significantly lower in bcsp- and pklps-vaccinated mice, compared with those of nonvaccinated control mice. Monophosphoryl lipid A enhanced the suppression of splenic infection when given with the bcsp vaccine, but not when given with the pklps vaccine. Trehalose dimycolate had no effect on mean cfu when given with bcsp, but incorporation of tdm resulted in a significant increase in mean cfu when given with pklps. Spleen weights in bcsp- or pklps-vaccinated mice were not different when these vaccines were combined with mpl or tdm. Because of the wide variation in the results, we could not conclude that vaccination with bcsp or pklps alone, or in combination with mpl altered spleen cell interleukin-1 production in B abortus-infected mice. Increased host protection as defined by decreased cfu could not be related consistently to increased bcsp- or pklps-specific serum IgG or IgM antibodies introduced by any of the vaccines. These results do not eliminate a role for antibodies in the protection observed.

Free access
in American Journal of Veterinary Research

Summary

Two distinct monoclonal antibodies (mab) were prepared for testing with kidney, spleen, and retrobulae tissue imprints made from chinook salmon (Oncorhnchus tshawytscha) affected with plasmacytoid leukemia. (pl). Hybridomas were prepared from mice immunized with whole and lysed cells purified from renal or retrobular pl-positive tissues, which had been obtained from naturally and experimentally infected fish from British Columbia, Canada. The mab reacted with at least 4 morphologically different cell types; of fluorescence was associated with the plasma membrane and cytoplasm. The mab also reacted with kidney imprints made from chinook salmon affected with a pl-like lymphoproliferative disease in California, indicating that these 2 diseases might be caused by a similar agent. The mab did not react with any of the kidney or spleen imprints made from wild chinook salmon collected from a river in Ontario, Canada

Free access
in American Journal of Veterinary Research

Summary

Polyclonal rabbit antiserum to human T-cell CD3 was used to study its reactivity in lymphoid tissues (lymph nodes, spleen, aggregated lymphoid follicles [Peyer's patches], thymus) of several animal species (cattle, sheep, goats, rats, and mice). Using a peroxidase-antiperoxidase technique on formalin-fixed and paraffin-embedded tissues, immunoreactive cells were detected in T cell-dependent areas of the lymphoid tissues. Reactivity was high in all species tested, but mouse tissues had reduced reactivity, compared with the other species. To obtain a reaction, it was necessary to digest tissues with pronase before application of the immunocytochemical technique. Our results indicate that CD3 antiserum may specifically recognize T-lymphoid cells as it does in human lymphoid tissues and can be used as a marker to study physiologic and pathologic conditions of the lymphoid system of these species.

Free access
in American Journal of Veterinary Research

Summary

The B1 strain of Newcastle disease virus (ndv-B1), which is nonpathogenic for newly hatched chickens, killed embryos when it was used to inoculate chicken eggs at embryonation day 18. Treatment of ndv-B1 with an alkylating agent, ethylmethane sulfonate (ems) markedly reduced the pathogenicity of the virus for 18-day-old chicken embryos. Eggs inoculated with the modified virus (ndv-B1-ems) hatched, and the virus was isolated from lungs and spleen of 1-day-old chickens. The hatched chickens developed antibody to ndv and were protected against challenge exposure (at 4 weeks of age) with a highly virulent GB-Texas strain of ndv. Presence of maternal antibody to ndv in embryonating eggs did not influence the protective ability of ndv-B1-ems, which also induced protective immunity when administered to 4-week-old chickens. The 50% protective dose of ndv-B1-ems in maternal antibody-negative and -positive embryos was calculated to be 10.77 and 17.70 embryo 50% lethal doses, respectively. Results of the study indicated that ndv-B1-ems may be used as an embryo vaccine to protect chickens against Newcastle disease.

Free access
in American Journal of Veterinary Research

SUMMARY

Effects of immunosuppression were compared in newly hatched chickens given cyclophosphamide (cy) after inoculation with avian nephritis virus (anv). All cy-treated infected chickens died within 13 days after inoculation of the virus and had heavy urate deposits throughout the body. However, non-cy-treated infected, cy-treated noninfected, and non-cy-treated noninfected control chickens survived through the observation period. In a chronologic study, the value of serum uric acid in cy-treated infected chickens was more than 3 times higher than that in non-cy-treated infected chickens, and more than 9 times higher than in noninfected chickens. Serum uric acid values were coincident with the positive degree of anv antigen in the tubular epithelial cells in the kidneys and with the severity of renal degeneration. Serologic and immunohistologic examinations did not reveal detectable antibody and IgG- and IgM-containing cells in the spleen and kidneys of cy-treated infected chickens. However, non-cy-treated infected chickens had an increased number of IgM- and IgG-containing cells and antibody against anv on postinoculation day 6. These findings demonstrated that cy treatment enhanced the susceptibility of chickens to anv infection.

Free access
in American Journal of Veterinary Research

Summary

The polypeptides of serologically related viruses of hemorrhagic enteritis (he) in turkeys, marble spleen disease (msd) in pheasants, and splenomegaly in chickens (smc) were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page) and analyzed by protein immunoblotting with polyclonal antibodies to he virus (hev). The viral polypeptides II, III, IV, V, VI, and VII were detected on sds-page with the size range from 18 to 97 kDa in hev. Viral polypeptides II, III, V, VI, and VII were detected in msd virus and virus of smc. Protein immunoblotting of viral proteins with anti-hev serum revealed antigenic differences between the 3 viruses of avian adenovirus type-II examined. The differences were that the polypeptides II, III, IV, V, VI, and VII were identified in hev and the polypeptides II, V, VI, and VII were identified in msd virus and virus of smc. The bands of penton base (polypeptide III) and fiber (polypeptide IV) were seen in hev only by protein immunoblotting.

Free access
in American Journal of Veterinary Research

Abstract

Objective

To evaluate stable rough mutants derived from Brucella melitensis 16M and B suis 2579 (biovar 4) as vaccines against homologous and heterologous Brucella spp in the BALB/c mouse model.

Design, Animals, and Procedure

Rough mutants VTRM1 and VTRS1 were obtained from B melitensis 16M and B suis 2579, respectively, by allelic exchange of the rfbU gene encoding mannosyltransferase with a Tn5-disrupted rfbU gene. Mice were vaccinated with VTRM1 or VTRS1 and challenge exposed 8 weeks later.

Results

VTRM1 and VTRS1 replicated extensively in the spleen during the first 3 weeks of infection, then decreased rapidly. Antibodies specific for the O polysaccharide were not detected in sera of mice inoculated with either rough strain. Vaccination with VTRM1 or VTRS1 induced protection against virulent strains of B abortus (2308), B melitensis (16M), B suis biovar 1 (750), and B suis biovar 4 (2579). VTRM1 also protected against B ovis (PA) and against 4 field isolates of B abortus from bison or elk. VTRS1 conferred protection against 4 field isolates of B suis biovar 4 from reindeer. Vaccines prepared from live VTRM1 or VTRS1 provided significantly greater protection than that afforded by vaccines of killed cells in QS- 21 adjuvant. Vaccination with VTRM1 containing VTRS1 gave minimal protection against the antigenically unrelated Listeria monocytogenes, thus demonstrating the immunologic specificity of protection against Brucella spp.

Conclusions and Clinical Relevance

Results encourage evaluation, in primary host species, of VTRM1 and VTRS1, along with RB51, as alternative vaccines to strain 19, Rev 1, or other smooth phase vaccines. (Am J Vet Res 1996; 57:677–683)

Free access
in American Journal of Veterinary Research

SUMMARY

A study was conducted to determine the immune (increased antibody) and protective (reduced colony-forming units) responses induced in mice by a: (i) single vaccinal inoculation, using various concentrations of Brucella cell surface protein (bcsp) or lipopolysaccharide (lps); (ii) primary inoculation, using various concentrations of bcsp, followed by a secondary inoculation, using a standard concentration of bcsp; and (iii) primary inoculation, using 1 concentration of bcsp or lps, followed by a secondary inoculation, using various concentrations of bcsp or lps. Four weeks after the primary inoculation, mice were challenge exposed with approximately 1 × 104 colony-forming units of Brucella abortus strain 2308 and all mice were euthanatized at 6 weeks. Reduced splenic weights and reduced colony-forming units in the spleens of vaccinated mice, compared with nonvaccinated mice, were the criteria of protection. Increase in serum IgM and IgG was defined as immunity.

Both bcsp and lps induced protective and immune responses that were proportional to the dose given up to an optimal limit. However, concentrations higher than optimal decreased the protective and immune responses. This was true for mice given either 1 or 2 vaccinal inoculations. Enhanced secondary protective responses were seen only when suboptimal doses were used in the primary inoculation. Excessive or optimal doses in the secondary inoculations prevented or obscured the protectiveness and immunity by primary inoculations. The protective effects appeared to be additive when suboptimal doses were used in the primary and secondary inoculations. Inoculation of subimmunogenic doses induced a relative reduction in the antibody concentration after challenge exposure, compared with nonvaccinated mice.

The overall results indicated that the protective responses induced by bcsp were probably attributable to lps. The results also indicated a linear increase in protection and immune response corresponding to increasing doses up to an optimal dose, and this stoichiometric optimum may be achieved by the use of 1 or more vaccinal inoculations. However, once this optimum was obtained, additional amounts of bcsp or lps cause perturbation of both the protective and serologic responses.

Free access
in American Journal of Veterinary Research