BCL6 and infection: Conversely, Bcl6 expression may bias against cytotoxicity, as increased numbers of mouse granzyme B+ CD4+ T cells have been shown to form in response to infection with Bcl6 deletion, although the population reported did not exhibit expression of other typical cytotoxicity genes (e.g., Pfr1, Gzma, Gzmm, Gnly, Klg1) [25].