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O Axelrod, GJ Silverman, V Dev, R Kyle, DA Carson and TJ Kipps
Department of Medicine, University of California, San Diego, La Jolla
92093-0945.
Monoclonal antibodies (MoAbs) specific for autoantibody-associated
cross-reactive idiotypes (CRIs) of Waldenstrom's IgM react frequently with
the surface Ig (slg) expressed by leukemia cells of patients with chronic
lymphocytic leukemia (CLL). Evaluation of the molecular basis for this
cross-reactivity indicates that such CRIs are encoded by conserved antibody
variable region genes (V genes) that have undergone little or no somatic
hypermutation. We find that such anti-CRI MoAbs stain a subpopulation of
cells within the mantle zones surrounding the germinal centers of normal
human tonsil. In contrast, MoAbs specific for variable region subgroup
determinants react with cells in both the mantle zones and germinal centers
of secondary B-cell follicles. To test whether mantle zone B cells not
reactive with existing anti-CRI MoAbs may express slg bearing
as-yet-unrecognized CRIs present on Igs produced by neoplastic cells of
some patients with Waldenstrom's macroglobulinemia or CLL, we immunized
mice with purified Waldenstrom's IgM that have been characterized for their
variable region subgroups using subgroup-specific antisera raised against
synthetic peptides. The supernatants of hybridomas generated from the
splenocytes of immunized mice were screened for their ability to stain a
subpopulation of mantle zone lymphocytes in human tonsil. With this
approach, two new anti-CRI MoAbs were identified, designated OAK1 and VOH3.
OAK1 binds to a CRI present on a subset of kappa light chains of the VK1
subgroup. VOH3 recognizes a CRI determinant(s) present on a subset of
antibody heavy chains of the VH3 subgroup. Flow cytometric analyses
demonstrated that OAK1 specifically binds leukemia cells from 5 to 20
patients (25%) with kappa light chain expressing CLL. In addition, VOH3
reacted with the leukemia cells from 1 of 17 (6%) patients tested. The
success of these methods demonstrates that the variable regions of the Igs
produced by mantle zone B cells share idiotypic determinants with Igs
expressed in B-cell CLL (B-CLL) and Waldenstrom's macroglobulinemia.
This article has been cited by other articles:
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| Copyright © 1991 by American Society of Hematology Online ISSN: 1528-0020 | |||||||||