A New Monoclonal Anti-CD3∊ Antibody Reactive on Paraffin Sections

Abstract

We generated a new monoclonal antibody (MAb), F7.2.38, by immunizing mice with CD3∊γδ/CD3ω complexes purified from human T-cells by OKT3 MAb–Sepharose affinity chromatography. Immunoprecipitation experiments and Western blotting analysis showed that MAb F7.2.38 recognized the CD3∊ chain in CD3∊ cDNA-transfected FOX B-cells and in various T-cell lines. Using flow cytometry on permeabilized or intact cells, the epitope was found to be located in the cytoplasmic tail of the CD3∊ chain. Immunohistochemical staining on paraffin-embedded sections showed that the reactivity of MAb F7.2.38 was comparable to that of the commercially available anti-CD3∊ polyclonal antibody. Of the 52 well-characterized T-cell lymphomas, 41 were positive for F7.2.38 (79%), whereas all 37 B-cell lymphomas and 69 non-lymphoid tumors were unreactive. This new anti-CD3∊ antibody would be particularly useful for phenotyping T-cell lymphomas on routinely processed paraffin-embedded tissue sections.