TNF and infection: In our study, old TNF KO mice recruited fewer circulating Ly6Chigh monocytes during S. pneumoniae colonization compared to old WT mice and counter-intuitively, this appeared to be protective against infection as when we depleted circulating Ly6Chigh monocytes using carboxylated polystyrene microparticles colonization, bacterial loads in the nasopharynx decreased.