T‐cell receptor antibodies in the immunohistochemical studies of normal and malignant lymphoid cells

Three anti‐T Cell receptor (TCR) antibodies, BF₁, BF₂, and WT31 were studied for their specificity and usefulness as immunohistochemical reagents. These antibodies were all satisfactory in the staining of normal peripheral lymphoid tissues and cortical thymic lymphocytes were reactive with BF₁ and BF₂ but not with WT31. Hassall's corpuscles in two of three thymuses studied reacted with all three antibodies. BF₁ was superior to the other two antibodies, especially for lymphoid cells in cytospin preparations. Fifty‐five lymphomas, 24 nonlymphoid malignancies, seven established cell lines, and five cases of large granular lymphocyte (LGL) proliferation with neutropenia were studied. The majority of non‐T‐cell lesions did not react with the antibodies. An occasional case showed weak reactivity which could be easily distinguished from the usual strong reaction with T‐cells. Tumor cells from over 90% of snap frozen peripheral T‐cell lymphomas reacted with BF₁ and BF₂. BF₁ was the preferred antibody since it gave a stronger and more consistent reaction. It was also the antibody of choice in identifying T‐lymphoblastic lymphomas. Michel's solution fixed tissue showed markedly diminished or absent reactivity with BF₂ and WT31, but BF₁ reactivity was less affected. Some unusual T‐cell phenotypes, with respect to the pattern of expression of BF₁ antigen and CD3, were observed. BF₁ and anti‐CD3, in combination, would be useful in identifying T‐cell lesions with aberrant or unusual TCR‐CD3 phenotypes.