TNF and infection: Relative to NMI, in vitro infection of primary human myeloid cells by NMII results in production of more pro-inflammatory cytokines, such as tumor necrosis factor (TNF), interleukin-12p70 (IL-12p70) and interleukin-1ß (IL-1ß), but ultimately both strains replicate similarly [3, 19, 28].