Research Article Both CD4+ and CD8+ Lymphocytes Participate in the IFN-γ Response to Filamentous Hemagglutinin from

Copyright © 2012 Violette Dirix et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Infant CD4+ T-cell responses to bacterial infections or vaccines have been extensively studied, whereas studies on CD8+ T-cell responses focused mainly on viral and intracellular parasite infections. Here we investigated CD8+ T-cell responses upon Bordetella pertussis infection in infants, children, and adults and pertussis vaccination in infants. Filamentous hemagglutinin-specific IFN-γ secretion by circulating lymphocytes was blocked by anti-MHC-I or-MHC-II antibodies, suggesting that CD4+ and CD8+ T lymphocytes are involved in IFN-γ production. Flow cytometry analyses confirmed that both cell types synthesized antigen-specific IFN-γ, although CD4+ lymphocytes were the major source of this cytokine. IFN-γ synthesis by CD8+ cells was CD4+ T cel