LOCALIZATION OF TLR2 IN INTESTINAL GOBLET CELLS OF EPTATRETUS CIRRATHUS

Eptatretus cirrhatus (New Zealand hagfish) is a member of the Myxinidae family, together with the lampreys form the group of primitive jawless fishes (Agnatha). The fish intestinal epithelium consists mainly of enterocytes (absorbing columnar cells), endocrine cells, immune cells and goblet cells that produce viscous mucus. The mucins, highly glycosylated proteins, plays an essential role in the lubrication and protection from intestinal bacteria and invasive pathogens. Goblet cells show a characteristic chalice shape and interact with the immune system that represents the first line of defense against the invasion of pathogens. Innate immunity involves a number of receptors to recognize microbial models such as complement of pathogen associated molecular patterns (PAMPs). Different types of TLRs have been identified in all classes of vertebrates. Ishii et al., (2007) have localized two types of TLRs in Petromyzon marinus (TLR14a and 14b, by PCR-based cloning using TLR2 sequences from various animals). Previous studies have shown that the activation of TLR2 on goblet cells during inflammation, stimulates mucus production. In this preliminary study, for the first time, intestinal mucous cells of Eptatretus cirrhatus were characterized using confocal immunofluorescence through use of TLR2 antibody. Our results showed goblet cells strongly labeled to TLR2, confirming that these cells are involved in immune defence. Furthermore, the localization of TLR2 in E. cirrhatus intestinal goblet cells demonstrates that this receptor was conserved in the phylogeny of vertebrates.