Human Serum Contains Detectable Levels of the Hsp70 Cochaperone HspBP1 and Antibodies Bound to HspBP1

Abstract The identification of the proteins that comprise the serum proteome is a current major research goal that will provide useful information for the diagnosis and treatment of various diseases. It is well established that Hsp70 and Hsp70 antibodies are present in human serum. This study reports on the development of an ELISA assay for the Hsp70 co‐chaperone, HspBP1. HspBP1 is present in human serum at concentrations ranging between 0.74 to 3.98 ng/mL. No gender or age differences in the HspBP1 levels were identified. It was also found that human serum contained antibodies to HspBP1, and there were no gender or age differences in these levels. In addition, there was no correlation between the level of HspBP1 in a sample and the antibody titer. Finally, we found that HspBP1 in serum is complexed to anti‐HspBP1 antibodies. This report provides initial baseline data on HspBP1 in human serum and provides the methods for future studies to determine if these levels are altered in response to disease.