DC development is dependent on the growth factor Flt3L, and exogenous administration has been shown to both increase the number of CD8α+ DC in the spleen of young mice (Maraskovsky et al., 1996; O’Keeffe et al., 2003) and the bacterial burden in the spleen following infection with Lm (Alaniz et al., 2004). This evidence concerns the gene FLT3LG and infection.