Renal allograft rejection. Functional impairment of kidney epithelial cell monolayers mediated by lymphokine-activated killer cells and by antibody.

A continuous line of human kidney epithelial cells was cultured to confluency on porous membranes, and the formation of intercellular tight junctions was monitored by measuring increases in the trans-monolayer electrical resistance. Typical monolayers developed functioning tight junctions within 4 days of culture and showed an increase in resistance of 1840 +/- 440 ohms (mean +/- SD; n = 5) at this time. Conventional Cr-21 release assays showed that suspended kidney cells were lysed by specific antibody and complement but were relatively resistant to lysis mediated by lymphokine-activated killer cells. However, when antibody and complement or LAK cells were added to functioning kidney cell monolayers the electrical resistance of the monolayers was rapidly reduced in both cases. In the absence of trans-monolayer resistance the ion gradients essential for renal tubular function will not be supported. These results indicate that the ability of a cytotoxic effector cell to liberate Cr-51 from suspended kidney cells may not be a sensitive assay for the ability of these effector cells to impair the function of structured kidney cell monolayers. It is possible that significant kidney dysfunction may occur during renal allograft rejection by failure of trans-epithelium resistance in the absence of widespread epithelial cell lysis.