When V. cholerae was injected alone, mRNA levels of tnfa and il1b incrementally increased throughout infection, mmp9 and cxcl18b levels were highly elevated at 6 hpi before decreasing by 18 hpi, and cxcl8a levels increased by 6 hpi but remained constant through 18 hpi (Fig 2A). This evidence concerns the gene MMP9 and infection.