In addition, enhanced secretion of TNF and NO, directly involved in the killing of intracellular parasites [68], in LdCen-/- infected BMDCs compared with LdWT infection clearly indicated that LdCen-/- parasites not only have impaired growth inside DCs, but they also induce a proinflammatory response in both age groups, suggesting that LdCen-/- parasites are safe and immunogenic in both age groups. The gene discussed is TNF; the disease is infection.