RESUMO
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. bovisDeltaRD1-, 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 with 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 with control after vaccination and challenge. IFNgamma expression was increased only after vaccination and secretion was higher in the control, non-protected group as compared with 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.
Assuntos
Antígenos de Diferenciação de Linfócitos T/sangue , Vacina BCG/imunologia , Bovinos/imunologia , Mycobacterium bovis/imunologia , Perforina/sangue , Tuberculose Bovina/prevenção & controle , Animais , Antígenos de Bactérias/imunologia , Antígenos de Diferenciação de Linfócitos T/biossíntese , Antígenos de Diferenciação de Linfócitos T/genética , Biomarcadores/sangue , Perfilação da Expressão Gênica , Interferon gama/biossíntese , Interferon gama/sangue , Interferon gama/genética , Linfócitos/imunologia , Mycobacterium bovis/genética , Perforina/biossíntese , Perforina/genética , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
The effector mechanisms used by CD4+ T cells to control mycobacteria differ between humans and rodent models of TB and should be investigated in additional animal models. In these studies, the bovine model was used to characterize the mycobactericidal CD4+ T cell response induced by vaccination with the attenuated Mycobacterium bovis bacillus Calmette-Guérin (BCG). Antigenic stimulation of peripheral blood CD4+ T cells from BCG-vaccinated cattle enhanced expression of perforin and IFNgamma in cells expressing a CD45RA-CD45RO+CD62L+ cell surface phenotype, enhanced transcription of granulysin, IFNgamma, perforin, IL-4, IL-13, and IL-21, and enhanced anti-mycobacterial activity of CD4+ T cells against BCG-infected macrophages.
