As shown in Figure 6E, CXCL13-expressing cells in CXCL5-/- mice included both lung tissue cells and lung leukocytes, while almost all CXCL13-expressing cells in WT mice were lung tissue cells at 3 d.p.i., which suggested that the increased expression of CXCL13 during the early infection stage was attributable to pulmonary lymphocytes. This evidence concerns the gene CXCL5 and infection.