Expression of immunoglobulin-cross-reactive molecules by neoplastic human T cells I. SURFACE DETECTION AND ISOLATION OF MOLECULES REACTIVE WITH CHICKEN ANTI-F(ab′)2, ANTI-α AND ANTI-μ ANTIBODIES.

There is evidence that the T-cell antigen receptor is immunoglobulin-related and that normal human T cells express surface determinants which cross-react with chicken anti-F(ab')₂, anti-α and anti-μ antibodies. Surface marker study of six neoplastic human T cell lines suggested that F(ab')₂- and μ-cross-reactive determinants may be expressed independently of ₂-cross-reactive determinants. F(ab')₂-cross-reactive materials-F(ab')₂-CRMs--were then isolated from several T-cell lines and analysed by reverse passive haemagglutination and in immunoprecipitation experiments by polyacrylamide disc gel electrophoresis in buffers containing sodium dodecyl sulphate (SDS-PAGE) under reducing conditions. It was shown that MOLT-4- and CCRF-CEM-derived F(ab')₂-CRMs differ serologically and that α- are indeed expressed independently of F(ab')₂- and μ-cross-reactive determinants. The F(ab')₂-CRMs were shown to be T cell-derived, to express determinants similar to or identical with F(ab')₂-cross-reactive determinants expressed in normal T-cell membranes and to correspond closely to T-cell antigen binding molecules. Evidence was also obtained that the two F(ab')₂-CRMS differ from one another in molecular weight. SDS-PAGE under non-reducing conditions of MOLT-4- and CCRF-CEM-derived F(ab')₂-CRMs identified major components of mol. wt. 135,000 and mol. wt. 330,000 respectively. Immunoprecipitation of ¹²⁵I-labelled F(ab')₂-CRMs by chicken anti-F(ab')₂ followed by SDS-PAGE under reducing conditions identified major components of mol. wt. 80,000 and mol. wt. of 51,000 from CCRF-CEM-derived F(ab')₂-CRMs and tentatively identified components of mol. wt. 52,000 and mol. wt. 23,000 from MOLT-4- derived F(ab')₂-CRMs. [ABSTRACT FROM AUTHOR]