Heterogeneity in the ability of IgG1 monoclonal anti‐D to promote lymphocyte‐mediated red cell lysis

Abstract

Thirty-four IgG anti-D human monoclonal antibodies (mAb) derived from 18 donor were assessed for their ability to mediate lysis of D+ red cells by lymphocytes in antibody-dependent cell-mediated cytotoxicity assays. Cell-bound antibody was quantified and the mAb were compared at similar levels of sensitization. The majority (23/31) of IgG1 and all (3/3) IgG3 mAb were ineffective; two donors produced both lytic and non-lytic anti-D mAb. Greater sensitivity was achieved using fluid-phase antibody (as culture supernatants) in the assay than was obtained with pre-sensitized red cells. Minimum levels of 2000 anti-D molecules per cell were required for lysis using pre-sensitized cells. Partial D red cells (DIVa, DVa and DVI) were lysed by three mAb that were lytic with normal D+ cells. There was no relationship between lytic ability and Gm allotype or D epitope specificity of the antibodies. Four mAb to other blood group specificities were tested: two (anti-E and anti-G) were lytic and two (anti-c and anti-Kell) were not lytic. Possible reasons for the heterogeneity of the lytic activity by the mAb are discussed.

Anti-RhD-Mediated Immunosuppression: Can Monoclonal Antibodies Imitate the Action of Polyclonal Antibodies?

“…2). Similar results were reported by Kumpel: only 5 out of 37 monoclonal anti-D IgG had a hemolytic activity in K-ADCC, and they were all obtained from one donor (Kumpel et al, 1989). A blend of the FcγRIIIA-nonactive monoclonal anti-D antibodies (pseudo-polyclonal anti-D) remained nonactive in ADCC+IG (data not shown).…”

Germline variable region gene segment derivation of human monoclonal anti-Rh(D) antibodies. Evidence for affinity maturation by somatic hypermutation and repertoire shift.

“…All these antibodies were produced by EBV transformation and the formation of human-mouse heterohybridomas. The antibodies Brad-3 and Jac-10 were obtained from two different donors; they were derived from EBV-transformed B lymphocytes and were kindly supplied by Dr. Belinda Kumpel (United Kingdom Transplant Service, Bristol, United Kingdom) (28). All the cell lines were clonal.…”

Characterization of a Macaque Anti-Rh17-Like Monoclonal Antibody

“…Tests for antibody dependent cellular cytotoxicity (ADCC) were performed using a standard procedure [12]. Human mononuclear cells were isolated on Ficoll-Hypaque from freshly drawn blood samples.…”