Compared to WT Mtb, infection of primary macrophages with Tn:Rv0431 resulted in secretion of much larger amounts of IL-10, IL-6, MCP-1, IL-12p40 and TNFα as judged by ELISA and higher levels of transcripts for GM-CSF and COX-2 as measured by qRT-PCR (Figure 5D and Figure S3A–B). Here, IL6 is linked to infection.