RETNLB and infection: In addition to altered secretion of mucin 2, the expression of RELM-B (resistin-like beta), TFF2 and TFF3 (trefoil factors 2 and 3), genes that encode for proteins exclusively produced by goblet cells, was also concomitantly down-regulated at 14 dpc, indicating a loss of mature goblet cells at the peak of infection [8].