Our laboratory continues to have a fundamental interest in the functional role of defined carbohydrate structures in directly regulating the human immune response. Based on our studies with Uromodulin which we purified, characterized and ultimately molecularly cloned from human pregnancy urine, we have characterized an entirely new class of immunoregulatory substances based on carbohydrate structure. A series of high mannose structures exhibit a broad range of imunoregulatory activity. We have expanded our source of these carbohydrate moieties and are examining their function utilizing three different approaches. The first involves structural studies using a combination of ion exchange chromatography, coupled with HPLC techniques.
Our aim i s to characterize the minimal structure required for biologic activity. The second is to characterize the in vitro and in vivo biologic activity of these compounds in a number of different models. The third approach examines the mechanism of action of these compounds at a molecular level. These studies demonstrate that defined glycopeptides are able to regulate immune activity both in vitro and in vivo. Interestingly these pure carbohydrate structures are able to directly regulate gene transcription by modulating the affinity and activity of transcriptionally regulatory proteins including the oncogene products c-fos and c-jun. These studies point the way toward a more basic understanding of factors responsible for gene regulation and hold the prospect of characterizing an entirely new class of pharmaceutically active compounds based on a unique chemistry. The laboratory has also undertaken two new projects which represent an extension of our previous studies on Uromodulin. First unpublished data from Dr. Vacquier's laboratory in San Diego demonstrate that sea urchin sperm exhibit a major protein with greater than 70% identity to Uromodulin. The protein retains such homology that our antisera against human uromodulin cross- react with the sea urchin protein. Using a human testicular cDNA library and a lambda gt11 expression system, we are in the process of trying to isolate the human analogue.
