Anti-CALLA antibodies identify unique antigens on lymphoid cells and
granulocytes
JM Pesando, P Hoffman, N Martin and T Conrad
The common acute lymphoblastic leukemia antigen (CALLA) is a 100-kd surface
glycoprotein that is present on normal and malignant lymphoid cells. It is
a useful marker for distinguishing between clinically important types of
acute leukemia. Anti-CALLA monoclonal antibodies (MoAb) also react with
mature myeloid cells (granulocytes), where they identify an antigen having
a similar molecular weight (mol wt). We now report that the antigens
detected by anti-CALLA MoAb on human lymphoid and myeloid cells differ in
their behavior and chemistry. Surface- labeling studies indicate that the
antigen on lymphoid cells has a mol wt of approximately 100 kd v 110 kd for
that on granulocytes. When cells are metabolically labeled with
35S-methionine, differences in the mol wt of these antigens are again
observed. Unlike the lymphoid antigen, expression of that on purified
granulocytes is not modulated by incubation with specific antibody. Sodium
dodecyl sulfate- polyacrylamide gel electrophoresis analysis of proteolytic
digests of the two antigens fails to clarify their chemical relationship.
Thus the antigens detected on these two cell types may share an epitope(s)
but be chemically distinct, or CALLA may exist in distinct forms and behave
differently on lymphoid cells and granulocytes.
Volume 67,
Issue 3,
pp. 588-591,
03/01/1986
Copyright © 1986 by The American Society of Hematology
