MPB70 is a highly species specific protein which is secreted from Mycobacterium bovis during culture. To investigate whether antibodies against MPB70 can be used as an indicator of infection with M. bovis, an enzyme-linked immunosorbent assay was developed, based on the use of biotinylated protein G, to provide a common indicator for antibody formation in different species. During experimental infection with M. bovis in cattle, a characteristic pattern of anti-MPB70 antibody production was observed with an initial fiat plateau followed by a marked rise 18 to 20 weeks after infection. Skin testing with bovine tuberculin purified protein derivative (PPD), which was shown to contain antibody-reactive MPB70, was a potent stimulator of antibody production in infected animals. In experimentally infected cattle, we observed an inverse relationship between antibody activity and delayed-type hypersensitivity skin test reactions. In natural M. bovis infections, skin testing with PPD was also a potent stimulator of anti-MPB70 formation. Comparison between the enzymelinked immunosorbent assay for antibodies to MPB70 and that for antibodies to the widely cross-reacting M. bovis BCG antigen 85B in animals with M. bovis, Mycobacterium avium, Mycobacterium paratuberculosis, and Corynebacterium pseudotuberculosis infections showed that formation of antibody to MPB70 was highly specific for infection with M. bovis. The use of an MPB70-containing PPD preparation for skin testing followed by this anti-MPB70 assay is a highly specific indicator of M. bovis infection. Adjustment of the test conditions is expected to provide an increased sensitivity of the procedure for the diagnosis of natural M. bovis infections.

Abstract. A retrospective histologic study was made of 1,198 cases of bovine lymphoma using the National Cancer Institute Working Formulation for human non-Hodgkin's lymphoma. This classification scheme was found to be readily applicable to bovine lymphoma. Most of the cell types described in the National Cancer Institute Working Formulation occurred in this series of bovine lymphomas, but the distribution of cell types varied markedly compared to that of human beings. Eighty-nine percent (1,067/1,198) of bovine lymphomas were high-grade tumors. The diffuse large cell type and its cleaved variant comprised 65.9% of all bovine lymphomas. Similar to the dog, but in marked contrast to human beings where at least 34% of non-Hodgkin's lymphomas were follicular, follicular tumors were found to be extremely rare in cattle (0.3% or 411,198). The prevalence of cell types varied significantly between the enzootic and sporadic lymphomas. The cleaved variant ofthe diffuse large cell type constituted 38% (406/1,072) of enzootic lymphomas versus 14% (1 8/126) of sporadic lymphomas. The mitotic index (100 x oil immersion field, 175 pm in diameter) of enzootic lymphomas (3.72 k 0.06, mean k standard error) was significantly greater than the mitotic index of sporadic lymphomas (2.82 f 0.17). We concluded that the cleaved variant of the diffise large cell type with high mitotic index is characteristic of enzootic lymphoma. This Characteristic high-grade cell type may be a consequence of the viral etiology of the enzootic form of bovine lymphoma.

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health sciences, history THE CANADIAN HISTORICAL REVIEW utpjournals.press/chr Offering a comprehensive analysis on the events that have shaped Canada, CHR publishes articles that examine Canadian history from both a multicultural and multidisciplinary perspective.

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