Optical biosensor technology has revolutionized the assessment of receptor
binding, enabling the characterization of low affinity interactions in real
time. We report the application of the IAsys(TM) Optical Biosensor to the
investigation of the affinity and specificity of the putative proximal tubu
lar scavenging receptor for protein reabsorption and the specificity of AGE
-modified protein interactions with primary human mesangial cells. Using th
e LLCPK cell line, the carboxy-methyl dextran cuvette surface and five diff
erent proteins (ranging in size and charge), we have shown that there is ev
idence to support the existence of a single scavenging receptor for all the
proteins tested The proteins competed with each other differing only in th
eir relative binding affinity for the common receptor. We have also shown t
hat human mesangial cells can bind to AGE-modified human serum albumin (AGE
-HSA) immobilized onto the carboxylate surfaced planar cuvette and that bin
ding can be inhibited using increasing concentrations of soluble AGE-HSA. H
owever, increasing concentrations of soluble Non-AGE modified HSA can also
inhibit binding to a similar extent which implies that there is relitively
little AGE- receptor (RAGE) expression on cultured primary human mesangial
cells. These results demonstrate the exciting potential of this technology
as a tool to explore cellular interactions with renal cells.