Submitted to: Immunology Research Workshop
Publication Type: Abstract Only
Publication Acceptance Date: 10/8/2003
Publication Date: 12/2/2003
Citation: Fach, S.J., Waters, W.R., Palmer, M.V., Davis, W.C., Sacco, R.E. 2003. Analysis of lymphocytes isolated from white-tailed deer (odocoileus virginianus) fawns. Immunology Research Workshop. December 2, 2003.
Technical Abstract: Peripheral blood mononuclear cells (PBMC) were isolated from ten female white-tailed deer fawns at 48 hours of age and every two weeks there after until the fawns were three months of age. Bone marrow aspirates and peripheral blood samples were taken on the same fawns at ten months of age (yearlings). In a separate experiment, mesenteric lymph node (MLN), spleen, thymus, bone marrow (BM) and peripheral blood (PB) were collected from euthanized female fetuses at approximately 190 days gestation (n=4) and from fawns at 24 hour (n=2), two weeks (n=2) and four weeks (n=2) of age. Mononuclear cells were isolated from pooled, homogenized tissues and individual peripheral blood samples at each of the four time points. 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 deer were also phenotyped using the same monoclonal antibody panel. Included in the panel were mAbs recognizing WC1, the g chain and d 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 the PB of fetal and neonatal fawns and decreased with age. In contrast, percentages of CD4**+ and CD8**+ populations were observed to increase over time in the PB. T cell surface antigen expression in the PB and tissues was consistent with observations made in other ruminants. 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 in the PB 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 in the PB, MLN, and spleen. 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 PB. The sIgM**+B-B2**+ population was observed in the fetal spleen and MLN. 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.