Submitted to: Wildlife Disease Association Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 8/2/2002
Publication Date: N/A
Technical Abstract: Peripheral blood mononuclear cells (PBMC) were isolated from female white-tailed deer fawns at 48 hours of age and every two weeks there after until the fawns were three months of age. Lymphocytes were phenotyped to examine the expression of specific surface receptors as the fawns aged. Three-color flow cytometric analysis of leukocytes was performed using a panel of monoclonal antibodies (mAb). Adult control deer were also phenotyped using the same monoclonal antibody panel. Included in the panel were mAbs recognizing WC1, the gamma chain and delta chains, CD4, CD8, CD62L, CD44, CD21, IL-2R, MHC Class II, B-B1, B-B2 and B-B4. Analysis revealed dynamic changes in the expression of specific surface receptors associated with development and maturation of lymphocyte subpopulations. WC1+ gamma delta T cells were predominant in neonatal fawns and decreased with age. In contrast, percentages of CD4 and CD8 populations were observed to increase over time. B cell surface IgM expression was heterogeneous at two days, but became more discrete as the fawns matured. Interestingly, B-B2, a putative B cell lineage marker expressed on lymphocytes at 24-48 hours was down modulated by two weeks. However, expression of another B cell lineage marker, B-B4, was consistently expressed throughout the fawns' development. Mononuclear cells isolated from bone marrow aspirates revealed phenotypically distinct expression of surface receptors as compared to PBMCs. Mononuclear cells co-expressing B-B2 and surface IgM were a unique population found in the bone marrow and not in the peripheral blood. B-B4 was expressed on a small percentage of bone marrow mononuclear cells. Proliferative responses of the isolated PBMC's to pokeweed mitogen (PWM), Concanavalin A (ConA) and Mannheimia (Pasteurella) haemolytica LPS were also examined. Cells isolated from fawns proliferated in response to PWM and ConA, but not in response to LPS stimulation. Data obtained in the present study provides baseline information regarding lymphocyte subpopulations in white-tailed deer fawns.