Monoclonal antibodies against the chronic lymphatic leukemia antigen cCLLa:
characterization and reactivity
GB Faguet and JF Agee
Monoclonal antibodies (MoAbs) were developed against the cCLLa, a 69-
kilodalton leukemia-associated antigen expressed on malignant cells of
B-type chronic lymphatic leukemia (B-CLL) and its variants: prolymphocytic
(PLL) and hairy cell leukemias (HCL). Two hybridomas yielded approximately
2 and approximately 7.5 mg/mL of IgG2a kappa and IgM kappa, respectively.
Monoclonal surface immunoglobulin-bearing cells of all B-CLL patients
studied (n = 30) reacted with the MoAbs (r greater than .99) regardless of
stage or lymphocyte count. This suggests that the malignant clone in CLL
can be identified and its size monitored by using our MoAbs. In contrast,
normal B lymphocytes, a large panel of normal, reactive and neoplastic
cells, and malignant cell lines failed to react with either MoAb as judged
by indirect immunofluorescence and by flow cytometry. Only two patients
(one with non-Hodgkin's lymphoma, the other with acute myeloblastic
leukemia) exhibited a small cell subset reactive with the MoAbs. cCLLa
specificity was suggested by selective target cell reactivity and
competitive inhibition-absorption and confirmed by immunoprecipitation.
MoAbs IgG2a kappa and IgM kappa appeared to share antigenic determinants
and were moderate and avid complement binders inducing 100% and 40% target
cell lysis, respectively. cCLLa density on malignant CLL and HCL cells was
estimated by equilibrium binding studies using the IgG2a kappa MoAb at 1.7
and 9 X 10(6)/cell, respectively. The restricted expression of the cCLLa
and the specificity and cytolytic activity of the anti-cCLLa MoAbs support
these antibodies as probes for the classification of lymphoproliferative
diseases and for the specific diagnosis and treatment of B-CLL and its
variants.
Volume 70,
Issue 2,
pp. 437-443,
08/01/1987
Copyright © 1987 by The American Society of Hematology
