Abstract
An immunotoxin specific for human T lymphocytes was prepared by coupling an IgG(2a) anti-CD3 murine monoclonal antibody (64.1) to purified ricin A chain (64.1-A). Treatment of blood mononuclear cells with this immunotoxin at a concentration of 1.7 x 10-9 mol/L for two hours at 37° C in the presence of 20 mmol/L NH4Cl decreased phytohemagglutinin-stimulated protein synthesis by 95%. In addition, a sensitive culture assay showed that fewer than 0.03% T cells remained after treatment of human bone marrow mononuclear cells with 64.1-A at a concentration of 1.7 x 10-9 mol/L. The inhibition of protein synthesis could be prevented by preincubating cells with unconjugated 64.1 antibody but not by preincubating cells with a control IgG(2a) antibody that binds to a different T cell antigen (CD5). At concentrations up to 1 x 10-8 mol/L, 64.1-A had little effect on blood mononuclear cells from baboons or human myeloid precursors (CFU-GM), which do not express the CD3 antigen recognized by 64.1. Taken together, these results indicate that the toxicity of 64.1-A was specific and the 64.1-A may be a useful reagent for depleting T cells from donor marrow as a means of preventing acute graft-v-host disease after allogeneic bone marrow transplantation.
Original language | English (US) |
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Pages (from-to) | 908-912 |
Number of pages | 5 |
Journal | Blood |
Volume | 66 |
Issue number | 4 |
DOIs | |
State | Published - 1985 |
ASJC Scopus subject areas
- Biochemistry
- Immunology
- Hematology
- Cell Biology