Abstract

Monoclonal antibodies specific for a variety of leukocyte differentiation antigens have been used in analytical flow cytometry to assess the routine health of killer whales over a four-year period. Relative percentages and absolute numbers of B lymphocytes (CD19 and CD21), T lymphocytes (CD2) and memory and naïve T lymphocytes (CD2 vs. CD45R) in peripheral blood were determined. Differential expression of MCH class II proteins on monocytes and lymphocytes was determined using two different monoclonal antibodies. Additional antibodies specific for leukocyte adhesion proteins, most for which human homologues have not yet been identified, were also employed. These antibodies were used to identify both the number of leukocytes (granulocytes, monocytes & lymphocytes) expressing these proteins and their individual cell-surface density. Leukocyte adhesion proteins are differentially expressed on a variety of leukocytes and play pivotal roles in cell-cell communication, lymphocyte traffic and inflammation-associated leukocyte extravasation.

Peripheral blood samples were analyzed at the originating park for CBC and blood chemistries on a routine basis (every 2 to 4 weeks), unless apparent clinical or behavioral changes suggested otherwise. Parallel blood was obtained every two months and sometimes more often in animals with apparent clinical or behavioral problems, in acid/citrate/dextrose and transported to the Davis laboratory via next-day delivery service for analytical flow cytometry. Health records included mention of apparent clinical disease or behavioral abnormality; on-going drug treatment was also noted. Data was analyzed using Statistical Analysis Software. While analysis is on-going, correlations have been established between flow cytometry data (i.e., circulating B lymphocytes), animal health and classical markers of inflammation/clinical disease (fibrinogen, iron, CBC, etc). The potential for analytical flow cytometry to identify perturbations in animal health, prior to appearance of abnormalities in behavior, clinical health, hematology or clinical chemistries, will be discussed.