Production and characterization of new monoclonal antibodies that distinguish subsets of mink lymphoid cells

Several hybridoma clones that produce monoclonal antibodies (MAbs) reacting with subpopulations of mink lymphoid cells were established. Two of the MAbs, MTS-4.3 and MTS-9.3, reacted with relatively small populations of surface immunoglobulin (Ig)-negative (Ig^-) lymphocytes. MTS-4.3⁺ and MTS- 9.3⁺ cells were distributed in the thymic cortex and medulla, paracortical areas of lymph nodes, and periarterial lymphoid sheaths of the spleen, indicating that these MAbs identify T lymphocytes. Another MAb, MTB-5.6, reacted with a large proportion of surface Ig⁺ lymph node cells, but not with surface Ig^- cells. In immunohistochemistry this MAb stained dendritic epithelial cells of thymic cortex, large polygonal cells of thymic medulla, a large proportion of lymphocytes in the mantle zone of lymphoid follicles, dendritic-shaped cells of paracortical area, and some lymphocytes and macrophage-like cells of medullary cords and sinuses of lymph nodes. The expression of the cell-surface antigen reacting with MTB-5.6 on Ig⁺ lymph node cells was increased after concanavalin A stimulation. These new reagents may be useful to analyze cellular basis of the abnormal immune responses observed in Aleutian mink disease, a classical model of human autoimmune diseases.