Research interests

Studies in this laboratory are focused on several areas of immunosuppression and immunoregulation.

The interaction of tumor cells and the immune system is at present poorly understood. The presence of a tumor cell coat comprised of a carbohydrate rich sialomucin may contribute to the survival of tumor cells. This sialomucin has been proposed to mask cell surface antigens and thus protect the tumor cells from detection or interaction with the host immune system.

This laboratory has been investigating a rat mammary tumor cell ascites which expresses a dominant cell surface sialomucin. These tumor cells are also resistant to lysis by natural killer (NK) cells. Loss of the major sialomucin by in vitro culture or treatment with tunicamycin, an inhibitor of glycoprotein synthesis, results in increased susceptibility to NK cell mediated lysis. One mechanism by which sialomucin appears to protect tumor cells is by providing resistance to the cytolytic granules released by NK cells. Studies of other protective properties of the sialomucin are underway.

Other projects involve studies of immunosuppression in pregnant and neonatal animals. We have studied the relationship between the levels of hormones progesterone and cortisol and immunosuppression in dairy cows. Although several reports suggest that these hormones are not immunosuppressive when added directly to in vitro assays, our results demonstrate a strong correlation between immunosuppression and levels of hormones in serum samples.

Other studies center around the role of carbohydrate in lymphokine clearance. The carbohydrate portion of uromodulin, a glycoprotein isolated from pregnancy urine, has been shown to bind lymphokines and studies of factors which influence glycosylation of uromodulin are planned.

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