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  • Author or Editor: Charles O. Thoen x
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in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

SUMMARY

Six monoclonal antibodies (mab) to virulent Mycobacterium bovis ATCC 19210 were produced, using a suspension of heat-inactivated whole cells. Immunoglobulin isotype for mab VMB6, VMB73, and VMB93 was IgG1, and for VMB31, VMB99, and VMB119, it was IgG2a. Monoclonal antibodies were examined for cross-reactivity to M tuberculosis, M kansasii, M fortuitum, M paratuberculosis, M avium serovars 1, 2, 4, 8, and 10, M chelonei, M phlei, M scrofulaceum, M smegmatis, Nocardia asteroides, and Rhodococcus equi. Monoclonal antibodies could be grouped on the basis of binding activity by elisa and immunoblot analysis, in which mab VMB6, VMB31, and VMB119 had binding activity to M bovis; mab VMB93 and VMB99 detected M bovis and M tuberculosis antigens, and mab VMB73 reacted with other mycobacterial species, as well as with N asteroides and R equi. Apparent molecular mass of antigens was 30 to 25 kilodaltons (kD) for VMB6, VMB31, and VMB119 and 63 kD for VMB93 and VMB99, and ranged from > 200 to 31 kD for VMB73, as estimated by immunoblot analysis. Monoclonal antibody binding activity to 18 field isolates of M bovis was evaluated, using elisa. Each of 18 field isolates was detected, using mab VMB6, VMB31, or VMB119; 10 isolates were detected, using mab VMB93/VMB99, and 14 were detected by use of mab VMB73. Use of mab in elisa failed to detect antigens from M bovis strain AN-5.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To monitor by use of 5-color flow cytometry the antigen-specific responses of subsets of peripheral T cells in cattle inoculated with a killed Mycobacterium avium subsp paratuberculosis (MAP) vaccine and to compare results with those for 2 established cell-mediated immunity assays.

Animals—45 female Holstein cattle with negative results for MAP in skin tests conducted at time of inoculation with MAP.

Procedures—Cattle were allocated to 4 groups. Cattle of group 1 (n = 12) were 0 to 3 months old and inoculated with a killed MAP vaccine. The 10 cattle of group 2 were the same age as those in group 1 but were not inoculated with MAP vaccine. The 11 cattle of group 3 were 9 to 12 months old and inoculated with killed MAP vaccine. The 12 cattle of group 4 were the same age as those in group 3 but were not inoculated with MAP vaccine.

Results—Flow cytometry identified T-cell subsets that responded specifically to the recall antigen. Results of assays for CD25 expression and wholeblood interferon-γ had the strongest correlation with results for skin tests as well as results with each other. Intracellular expression of interferon-γ was not correlated as well with results for the other tests.

Conclusions and Clinical Relevance—Flow cytometry can be useful for characterizing the immune response after administration of MAP vaccine and should be evaluated with regard to its sensitivity and specificity when used in detecting cattle naturally infected with MAP.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether cats exposed at a residence were infected with Mycobacterium bovis, whether the tuberculin skin test can identify cats infected with M bovis, and whether an ELISA could identify tuberculosis-infected cats.

Animals—20 domestic cats exposed to a cat with laboratory-confirmed disseminated M bovis infection.

Procedure—Cats were administered a tuberculin skin test and monitored for 72 hours. Blood and fecal samples were collected. Cats were then euthanatized, and postmortem examinations were performed. Tissues were examined grossly and histologically for signs of mycobacteriosis. Pooled tissue samples and fecal samples were submitted for mycobacterial culture. Blood samples were examined for evidence of tuberculosis by use of a comparative ELISA.

Results—4 cats had positive responses for the ELISA, and 2 cats had suspicious responses. All tuberculin skin tests yielded negative results. No gross or histologic lesions of tuberculosis were detected in any tissues, and mycobacteria were not isolated from tissues or feces obtained from the 20 cats.

Conclusions and Clinical Relevance—All cats that had positive or suspicious responses for the ELISA were offspring of the cat with tuberculosis. Evidence of tuberculosis was not seen in other cats at the residence, the owner, or the attending veterinarian. The most likely source of tuberculosis for the infected cat was through the consumption of M bovis-infected wildlife carcasses or offal. Because M bovis is endemic in wildlife in northeastern Michigan, there is a risk of exposure to tuberculosis in companion animals, their owners, and attending veterinarians. (Am J Vet Res 2002;63:1507–1511)

Full access
in American Journal of Veterinary Research