We also observed cooperativity phenomena in IL-13 and IL-13R interaction in control RCC (MLneo) cells, but not in cells transfected with gammac chain (MLgammac).
Even though IL-13 and IL-4 are homologues and IL-4R and IL-13R have been proposed to share a receptor subunit, IL-4 did not compete for the cytotoxicity mediated by IL13-toxin on RCC.
We report, for the first time, that IL-4 and IL-13 can up-regulate protein expression as well as enzymatic activity of both the peptidases on renal carcinoma cells and renal tubular epithelial cells in culture.