Absence of repopulating lymphocytes during nonresolving inflammation. (A) Zymosan was injected into the peritoneal cavity of pg91^phox knockout mice, which, when compared with controls, showed a more aggressive inflammatory response that failed to resolve. (B) FACS analysis of cell types present during resolution revealed a progressive repopulation of lymphocytes during resolution that was lower in pg91^phox knockout mice. (C) Lymphocytes obtained from the resolution phase (72 hours) of normal strain-matched wild-type controls and comprising B1 cells, NK cells, and γ/δ T cells, as well as CD4⁺/CD25⁺ cells, were transferred back into the peritoneal cavity of gp91^phox knockout mice (72 hours) and subsequently challenged, intraperitoneally, with LPS. Inflammation was reduced in gp91^phox knockout mice that received resolution-phase lymphocytes compared with gp91^phox mice alone. *P ≤ .05; **P ≤ .01 as determined by ANOVA, followed by Bonferroni t test, with data expressed as means plus or minus SEM.