Generation of heterogeneous memory T cells by live attenuated tularemia vaccine in humans

There is very limited evidence concerning the phenotype, function. and homing characteristics of memory T (T(M)) cells elicited by vaccination against intracellular bacteria in humans Here we studied T(M) subsets elicited by exposure to Francisella tularensis in humans as a model of immunity to intracellular. bacteria. To this end. T(M) cells were evaluated in two groups (1) subjects immunized with live attenuated tularemia vaccine by skin scarification and (2) tularemia naturally infected subjects In both groups the immune responses were mediated by CD4(+) and CD8(+) effector T(M) cells, mostly CD45RA(-)CD62L(-) and CD45RA(+)CD62L(-) Based on the expression of CD27. integrins alpha(4)/beta(1). and alpha(4)/beta(1), it is likely that some of these T(M) cells have lytic potential and the ability to enter both mucosal and non-mucosal sites Thus, regardless of whether by immunization or natural exposure. tularemia antigens elicited a broad spectrum of specific T(M) subsets with diverse homing characteristics (C) 2009 Elsevier Ltd All rights reserved