CTLA4 and bacterial infectious disease: Pedicord et al. found that not only does blockade of CTLA-4 during a memory response lead to a better CD8+ recall response against bacterial infection but also that anti-CTLA-4 given during the primary response results in an enhanced CD8+ memory recall response, suggesting that CTLA-4 upregulation during priming imprints a differentiation program that impedes memory function.