Monoclonal antibodies identifying feline haemopoietic cell lineages

Abstract

Monoclonal antibodies (MAbs) were prepared against feline bone marrow mononuclear cells. Immunogold immunofluorescence (IGIF), flow cytometry and fluorescence activated cell sorting (FACS) were used to determine the selective reactivity of four MAbs, designated FeMy, FeLy and FeEr1/Er2 with feline myeloid (granulocyte/macrophage), lymphoid, and erythroid lineage cells, respectively. Reactivity was also assessed to four feline lymphoma cell lines (3201, 3191, 3281, FL74). FeMy reacted with 74% of all myeloid lineage cells (88% of mature and 30% of early myeloid progenitors), 98% of blood neutrophils, 97% of eosinophils and 90% of monocytes. FACS of bone marrow using feMy yielded 89% myeloid lineage cells. FeLy reacted with 67–75% of lymphoid lineage marrow cells IGIF and flow cytometry. However, FeLy also recognised a surface molecule present on 30% of erythroid precursors, 86% of eosinophils, and three of four feline lymphoma cell lines. FACS of marrow cells using FeLy yielded 77% lymphoid cells (and 19% myeloid cells). FeErl and FeEr2 (which identified either the same or closely associated molecules) reacted with 55–66% of early erythroid and 90–95% of late erythroid lineage marrow cells but not with mature erythrocytes by immunogold immunofluorescence. Marrow FACS using FeErl and FeEr2 yielded 76–80% erythroid cells (and 18–21% myeloid progenitors). Wheres FeLy immunoprecipitated a 120 kDa molecule, neither FeMY nor FeErl and FeEr2 precipitated an identifiable molecule. The panel of MAbs described may be useful in immunophenotyping of feline haemopoietic neoplasia.