The monoclonal antibody TER-119 recognizes a molecule associated with glycophorin A and specifically marks the late stages of murine erythroid lineage

The antigen specificity of a rat monoclonal antibody TER-119 was investigat ed. In adult mice, TER-119 reacted with mature erythrocytes, 20-25% of bone marrow cells and 2-3% of spleen cells but not with thymocytes nor lymph no de cells. In fetal haematopoietic tissues, 30-40% of d 10 yolk sac cells, 8 0-90% of d 14 fetal liver cells and 40-50% of newborn liver cells were reac tive with TER-119. TER-119(+) cells in adult bone marrow ex-pressed signifi cant levels of CD45 but not myeloid (Mac-1, Gr-1) or B-cell (B220) markers. Morphological examination and haematopoietic colony-forming assays for iso lated TER-119(+) cells revealed that TER-119 reacts with erythroid cells at differentiation stages from early proerythroblast to mature erythrocyte, b ut not with cells showing typical erythroid blast-forming unit (BFU-E) and erythroid colony-forming unit (CFU-E) activities. Erythroleukaemia cell lin es do not express the TER-119 antigen even after stimulation with dimethyls ulphoxide. TER-119 immunoprecipitated protein bands with molecular masses o f 110 kDa, 60 kDa, 52 kDa and 32 kDa from erythrocyte membrane, whereas onl y a 52-kDa band was detected by TER-119 in Western blot analysis. Further m olecular and cellular analyses indicated that the TER-119 antigen is a mole cule associated with cell-surface glycophorin A but not with glycophorin A itself.