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Description:
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The development of improved vaccines against tuberculosis (TB ) is directly linked to the investigation of new and better correlates of protection after vaccination against TB . Cloning and characterization of bovine homologues of the antimicrobial protein granulysin (Bo -lysin ) and perforin by our group could be used as potential biomarkers for TB vaccination efficacy . In the present study we examined the kinetics of granulysin , perforin , IFNgamma and Fas -L responses to Mycobacterium bovis purified protein derivative (PPD ) stimulation by peripheral blood mononuclear cells from M . bovis DeltaRD1 - , BCG - and non -vaccinated cattle . Gene expression profiles following PPD stimulation showed significant increases in transcripts for granulysin and IFNgamma in both CD4+ and CD8+ T cells in BCG -vaccinated as compared to non -vaccinated animals . Perforin and IFNgamma examined by flow cytometry , showed a difference of 1 -2 % more PPD -specific cells in BCG -vaccinated than non -vaccinated animals . In the vaccine trial , granulysin and perforin were significantly increased in both vaccine groups as compared to control after vaccination and challenge . IFNgamma expression was increased only after vaccination and secretion was higher in the control , as compared to both vaccine groups demonstrating no correlation with protection upon vaccination . In summary , results shown here provide evidence that granulysin and perforin are prospective candidates as biomarkers of protection after vaccination against TB . |