The CD43 extracellular domain is required for T-cell trafficking to lymph nodes. Resting DO.CD43^−/− T cells transduced with either CD43-FL or CD16–7-43 were mixed in equal numbers and injected into BALB/c mice (n = 8). After 16 hours, the frequency of donor CD43⁺ or CD16⁺ CD4 T cells were enumerated in the blood, spleen, and lymph nodes. Data are the mean (± SEM) of the ratio of the frequencies of CD16⁺ to CD43⁺ CD4 T cells in various organs. Data shown are representative of 2 independent experiments with at least 8 mice each. (**P < .01; ***P < .001).