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A western blot characterization of Mycobacterium bovis antigens recognized by cattle sera
A Cataldi1, M I Romano, F Bigi
1Instituto de Biología Molecular, CICV/INTA, Moron, Argentina.
Insights
This study analyzed cattle immune responses to Mycobacterium bovis using Western blot. Key findings show whole cell antigens are more frequently recognized than secreted ones, with a 28-kDa protein being a major antigen in late-stage bovine tuberculosis.
Area of Science:
- Veterinary Immunology
- Bacteriology
- Protein Chemistry
Background:
- Bovine tuberculosis, caused by Mycobacterium bovis, poses a significant threat to cattle health and global food security.
- Accurate diagnostic tools are crucial for controlling the spread of bovine tuberculosis.
Purpose of the Study:
- To characterize the antibody recognition patterns against Mycobacterium bovis antigens in cattle sera.
- To identify specific antigens that elicit differential immune responses based on the stage of bovine tuberculosis.
Main Methods:
- Western blot analysis was employed to detect antibody responses.
- Sera from M. bovis-infected (n=62) and healthy (n=38) cattle were tested against M. bovis whole cell extracts and culture supernatant antigens.
- Monoclonal antibodies were used to characterize a specific 28-kDa protein.
Main Results:
- Antibody recognition patterns were highly variable but identified several consistently detected proteins (17, 23, 28, 42, 66, 71, 80 kDa in cell extracts; 23, 33 kDa in supernatants).
- Whole cell extract antigens showed higher recognition frequency compared to culture supernatant antigens.
- A 66-kDa stress protein response was observed in intermediate stages, while a 28-kDa cellular protein and supernatant antigens were prominent in late-stage disease.
Conclusions:
- Whole cell extract proteins are generally more immunogenic than secreted proteins from M. bovis.
- A 28-kDa protein emerges as a significant antigen in cattle with advanced bovine tuberculosis, suggesting its potential diagnostic value.
Abstract:
The immune response to Mycobacterium bovis in cattle was assessed by Western blot. The antibody recognition pattern to M. bovis whole cell extracts and culture supernatant antigens was studied by using sera from M. bovis-infected (n = 62) and healthy (n = 38) cattle. Although the recognition patterns were highly variable, some proteins were regularly detected, mainly those with molecular masses of 17, 23, 28, 42, 66, 71 and 80 kDa in cellular extracts, and with molecular masses of 23 and 33 kDa in supernatants. Whole cell extract antigens were more frequently recognized than culture supernatant antigens. Healthy controls produced only a weak antibody response. The antibody response was variable, depending on tuberculosis stage. In early stages very few antibodies were detected. A response against the 66-kDa stress protein was mounted in intermediate tuberculosis and remained stable in more advanced disease. In late diseases, the preferentially recognized antigens were a 28-kDa cellular protein and supernatant antigens. The 28-kDa protein was studied in some detail. As determined by using monoclonal antibodies, the 28-kDa protein is different from superoxide dismutase. This protein aggregated in stored cell extracts and was not totally transferred to nitrocellulose. The principal conclusions of this work are: (i) whole cell extract proteins are more frequently recognized than the secreted proteins and (ii) a 28-kDa protein is a major antigen in late disease.
