Evaluation of monoclonal antibodies for identification of subpopulations of myeloid cells in bone marrow obtained from dogs

Objective To evaluate monoclonal antibodies that may be useful for immunoph enotyping myeloid cells in bone marrow of dogs. Sample Population-Bone marrow specimens obtained from 5 dogs. Design-Specimens were labeled with monoclonal antibodies that detected CD18 , major histocompatability antigen class-II(MHC class-II), CD 14, and Thy-1 . Cells labeled with each of the antibodies were isolated by use of a fluor escence-activated cell sorter. Differential cell counts of sorted cells wer e used to determine cells that were labeled by each of the various antibodi es, Results-Myeloid cells labeled with anti-CD18 antibody included granulocytes , lymphocytes, and monocytes-macrophages. Immature and mature granulocytes were labeled. Lymphocytes, monocytes-macrophages, and eosinophils were labe led with anti-Thy-1 antibody. Cells labeled with anti-MHC-class II antibody included approximately 9% of bone marrow cells, which consisted almost exc lusively of lymphocytes and monocytes-macrophages. Approximately 4% of bone marrow cells were labeled with anti-CD14 antibody, with > 90% of sorted ce lls being monocytes-macrophages. Conclusions and Clinical Relevance Four monoclonal antibodies for use in de tecting subpopulations of canine bone marrow cells were evaluated. These an tibodies should be useful in differentiating the origin of leukemic cells i n dogs.