Extent of HIV-1 tissue dissemination in humanized mice varies 1 week following intravaginal infection with high or low dose viral inoculum. The proportion of tissues positive for HIV-1 RNA (copies/mL) as detected by clinical real-time RT-PCR increased between 1 and 5 weeks post-infection, in Hu-mice challenged IVAG with either a low (103 TCID50 HIV-1 (NL4.3-BAL)) (A, B) or high dose (105 TCID50 HIV-1 (NL4.3-BAL)) (C, D) inoculum of HIV-1. The magnitude of viral RNA increased between 1 and 5 weeks post infection regardless of initial viral dose (A vs. B, and C vs. D). At 1 week post-infection, HIV-1 RNA could be detected in the lung and vaginal tract of a Hu-mouse infected with low dose HIV-1 (A), whereas 50% (9/18) of tissues were positive in a Hu-mouse infected with high dose HIV-1 (C). By 5 weeks post infection, Hu-mice infected with a low (B) and high dose (D) HIV-1 had comparable viral dissemination. Each graph represents tissues collected from a single infected Hu-mouse. Tissue dissemination in additional Hu-mice is described in Table 4. IVAG: intravaginal, LN: lymph node.