Expression patterns of IL-10 ligand and receptor gene families provide leads for biological characterization

The expression patterns of the IL-10 ligand and receptor genes were examined in normal and transformed cell lines of human hematopoietic and non-hematopoietic origin. IL-10 family ligands, IL-10, IL-19, IL-20, IL-22, IL-24 and IL-26 were predominantly expressed by hematopoietic cells. IL-10, IL-24 and IL-26 were produced by both monocytes and T cells, IL-19 and IL-20 were produced by monocytes whereas IL-22 was produced mainly by activated T cells. The receptors of the IL-10 family, IL-10R1, IL-10R2, IL-20R1, IL-20R2, IL-22R1 and IL-22 BP were also expressed in a distinct pattern when probed on these cell lines. The expression of IL-10R2 was ubiquitous whereas IL-10R1 was predominantly expressed on hematopoietic cells, including, T cells, B cells, NK cells, monocytes and dendritic cells. IL-20R1, IL-20R2 and IL-22R1 were absent or expressed at extremely low levels on cells of the hematopoietic lineage. These receptors were mainly found on epithelial and stromal cells fibroblasts of various tissues. Interestingly, IL-22BP was quite specifically expressed by dendritic cells. These data point to a function of the novel IL-10 family members in communication and interaction between cells of the hematopoietic and non-hematopoietic lineages, a role quite distinct from the immunomodulating effects of IL-10 itself.