(A) Antibiotics improve Foxc2lecKO mice survival. Treatment scheme and Kaplan-Meier survival curve of untreated and antibiotic-treated (Abx) WT mice and Foxc2lecKO mice *P < 0.05; n = 17 WT, n = 16 WT + Abx, n = 20 Foxc2lecKO, n = 17 Foxc2lecKO + Abx. (B) Ascites and pleural effusions in untreated and Abx-treated Foxc2lecKO mice. n = 10 Foxc2lecKO, n = 12 Foxc2lecKO + Abx. (C) Microbiota depletion rescues chyle stasis of Foxc2lecKO mice. Bright-field pictures, n = 7 Foxc2lecKO, n = 12 Foxc2lecKO + Abx. Scale bars, 1 mm. (D) Intestinal lymphangiectasia in Foxc2lecKO mice. Green, LYVE1; blue, DAPI. Scale bars, 50 μm. LV area normalized to tissue area. *P < 0.01; n = 9 WT, n = 9 WT + Abx, n = 5 Foxc2lecKO, n = 7 Foxc2lecKO + Abx. (E) Microbiota depletion abrogates omental FALC enlargement of Foxc2lecKO mice. Green, CD45; red, LYVE1. Scale bars, 100 μm. FALC size and number normalized to tissue area in WT and Foxc2lecKO mice. *P < 0.001 WT versus Foxc2lecKO; *P < 0.01 Foxc2lecKO versus Foxc2lecKO + Abx, n = 8 WT; n = 8 WT + Abx, n = 4 Foxc2lecKO; n = 7 Foxc2lecKO + Abx. (F) Microbiota depletion abrogates enlargement of peripheral Foxc2lecKO LNs. *P < 0.01 inguinal LN (ingLN) in WT versus Foxc2lecKO; *P < 0.05, popliteal LN (popLN) in WT versus Foxc2lecKO, n = 12 WT, n = 14 WT + Abx, n = 7 Foxc2lecKO, n = 10 Foxc2lecKO + Abx. Data are means ± SD.