Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/13/2010
Publication Date: 7/13/2010
Citation: Calderon, V.E., Silva, E., Santos, L., Waters, W.R., Palmer, M.V., Thacker, T.C., Jacobs, W.R., Larsen, M.H., Vilcheze, C., Estes, D.M. 2010. Granulysin as a Correlate of Immune Response following Mycobacterial Infection [abstract]. Interpretive Summary:
Technical Abstract: Correlates of protection following vaccination against TB are needed in the development of improved vaccines against TB. Evaluation of vaccine efficacy is based on measuring IFN gamma levels and antigen-specific proliferation. Granulysin is an antimicrobial protein expressed by T lymphocytes and NK cells, both peripherally and in granulomatous tissues, following TB infection. Previous studies from our laboratory have shown granulysin to be a prospective biomarker for protection following vaccination against TB. In addition, we have recently developed an IgG1 monoclonal antibody against granulysin to correlate protection in peripheral blood mononuclear cells (PBMCs) post vaccination and challenge. We wanted to determine if deletion of nadABC genes from Mycobacterium bovis (M. bovis) results in attenuation and if insertion of the pncA gene from M.tuberculosis restores virulence. We examined granulysin and IFN gamma responses to M. bovis purified protein derivative (PPD) stimulation in PBMCs from M.bovis Ravenel, M. bovis Delta nadABC, and M. bovis Delta nadABC pMV261::pncA challenged cattle. Granulysin and IFN gamma levels, examined by flow cytometry, showed significant increases in pncA challenged animals upon PPD stimulation. These results were further validated by an ELISA which demonstrated significantly increased IFN gamma levels to PPD stimulation in pncA animals. A cervical skin test exhibited a significantly higher immune reaction in pncA animals compared to M. bovis Ravenel and Delta nadABC challenged animals. Overall, these results indicate that granulysin responses correlate to IFN gamma responses following TB challenge in cattle.