Cynthia V. Sommer
     Graduate student
     Adviser: Yi-chi M. Kong
     Degree: Ph.D., 1974
     Title of thesis: The isolation and characterization of murine
          transplantation antigens


     Link to Cynthia at University of Wisconsin

Contact information (as of 6/1/04):
     Associate Professor, Emerita
     Department of Biological Sciences
     University of Wisconsin at Milwaukee
     Milwaukee, WI 53201
     Ph: (414) 229-4214
     Fax: (414) 229-3926
     Work email: wtscvs@uwm.edu
     Home email: NA

Current activity: My research focuses on the immune system of salmonid fishes. I am interested in understanding through laboratory and field studies, the immune defense mechanisms used by fish in response to infectious diseases. Specifically, we are studying the early synthesized defense proteins called acute phase proteins. Related research includes studying the immune response and genetic potential of trout to resist the pathogen that causes Bacterial Kidney Disease (BKD) in salmon. Two important acute phase proteins (APP) in trout include C - reactive protein (CRP) and transferrin. The concentration of these proteins in the blood changes rapidly following stress and infection. Acute phase proteins can interact with several types of white blood cells to amplify or control immune responses. We have isolated and characterized rainbow trout CRP from serum and liver tissue and demonstrated evolutionary differences between trout and human CRP. In contrast to human CRP, trout CRP is glycosylated, maintained at a higher serum level, increased at lower levels in response to infection, and binds to a larger percentage of lymphocytes. We have identified the types of terminal sugars on trout CRP and are investigating the functional roles of glycosylation on CRP. Our recent studies on the binding properties of CRP suggest that a specific CRP receptor exists on trout lymphocytes. The percentage of leukocytes with the ability to bind CRP differ among the various types of lymphoid tissues. Our lab is currently studying the role of trout CRP in regulating the function of these cells.
     One potential biological role of CRP is to help the immune system adapt to various environmental stresses. We have shown in rainbow trout that in stressful environments, such as low dissolved oxygen, increased chlorine levels and sub-acute ammonia toxicity, C-reactive protein increases. Additional studies using in vitro trout liver cell lines have demonstrated that following exposure to various metals, at levels commonly found in the environment, CRP functions as a positive APP and transferrin responds as a negative APP. Factors that regulate the expression of these proteins has been investigated using our in vitro culture system. Dexamethasone, metals and/or fibroblast conditioned media containing growth factors can affect the production of CRP and transferrin in trout hepatoma cells.
     The fish immune system is also essential for combating infections, such as Bacterial Kidney Disease (BKD). This disease, caused by the pathogen, Renibacterium salmoninarum, is a chronic infection of the kidney in salmonid fishes that results in large losses of fish. The economic impact of this disease on aquaculture is significant. We have developed monoclonal antibodies and ELISA tests to detect and quantitate the bacteria in fish and can associate environmental and nutritional conditions which increase disease susceptibility. Currently we are studying resistance of salmon to BKD and correlating it with gene markers (MHC) involved in immune function.