Reactivity profiles of leukemic myeloblasts with monoclonal antibodies
directed to sialosyl-Le(x) and other lacto-series type 2 chain
antigens:absence of reactivity with normal hematopoietic progenitor cells
K Muroi, T Suda, H Nojiri, H Ema, Y Amemiya, Y Miura, H Nakauchi, A Singhal and S Hakomori
Department of Medicine, Jichi Medical School, Tochigi-ken, Japan.
We investigated the expression profiles of lacto-series type 2 antigens in
hematopoietic cells and their progenitors, in comparison with leukemic
leukocytes. Reactivity profiles of various anti-type 2 chain monoclonal
antibodies (MoAbs) with leukemic blasts from 12 patients with acute
myeloblastic leukemia (AML) and those from two patients with acute
unclassified leukemia (AUL) show that anti-sialosyl-Le(x) MoAb SNH3 reacted
strongly with greater than 95% of leukemic blast leukocyte populations from
all patients (14 of 14). Another anti-sialosyl-Le(x) MoAb, FH6, showed less
reactivity than SNH3 (12 of 14 patients), while anti-Le(y) MoAb AH6 showed
reactivity with only 8 of 14 patients. On the other hand, none of the
anti-type 2 chain MoAbs reacted with CD34+ normal adult bone marrow (BM)
mononuclear cells obtained independently from three healthy volunteers.
MoAb SNH3, but not FH6 or AH6, showed complement-mediated cytotoxicity to
leukemic blasts from these patients, as well as to myelogenous leukemia
cell line HL60. Colony- forming unit granulocyte-macrophage (CFU-GM), but
not burst-forming unit-erythroid (BFU-E), was incompletely inhibited by
treatment of normal BM mononuclear cells with SNH3 and complement. The
absence of type 2 chain antigen expression in hematopoietic progenitor
cells and in in vitro hematopoietic colonies (CFU-GM and BFU-E) strongly
suggests that application of anti-carbohydrate MoAbs, particularly
anti-sialosyl- Le(x) could be useful for elimination of leukemic
myeloblasts infiltrating in BM, for purging of leukemic blasts in BM, and
for facilitation of autologous BM transplantation.
Volume 79,
Issue 3,
pp. 713-719,
02/01/1992
Copyright © 1992 by The American Society of Hematology
