Because of the significant variation in chlamydial burdens (from 105 inclusion-forming units [IFU] to undetectable) seen at later time points (day 10 and onward) in mice depleted of neutrophils and CD4+ T cells (Fig. 5), we hypothesized that perhaps effective depletion of neutrophils for an extended period (2 weeks or more) might not be achievable, which would result in premature infection resolution in some mice. Here, CD4 is linked to infection.