Selection and characterization of T-cell variants lacking molecules involved in T-cell activation (T3 T-cell receptor, T44, and T11): Analysis of the functional relationship among different pathways of activation

A clone of the interleukin 2-producing Jurkat leukemia cell line termed JA3 (surface phenotype, T3⁺, Ti⁺, T44⁺, T11⁺, T40⁺) has been used to induce and select cell variants lacking surface molecules involved in T-cell activation. Following 200 rad of γ-radiation (1 rad = 0.01 Gy), cells were treated with monoclonal antibodies (mAbs) directed to T3, Ti, T44, or T11 antigen and complement. After growth of the residual cells in culture, 'negative' cells were cloned under limiting conditions. Depending on the specificity of the mAb used for the immunoselection, three groups of variants were obtained. (i) The use of mAbs directed to T3 or Ti resulted in cell variants that expressed the T3^- Ti^- T44⁺ Leu1⁺ T11⁺ T40⁺ 4F2⁺ HLA class I⁺ surface phenotype. (ii) Immunoselection with anti-T44 mAb resulted in 2 variants that shared the T3^- Ti^- T44^- Leu1^- T11⁺ T40⁺ 4F2⁺ HLA class I⁺ phenotype. (iii) Cell treatment with anti-T11 mAb resulted in 15 variants characterized by the lack of T11 antigen expression and of all the other T-cell-specific surface antigens. Therefore, it appears that the different sets of JA3 cell variants, like T cells at discrete stages of intrathymic differentiation, may follow a coordinated expression of surface differentiation antigens. Analysis of the functional responsiveness of the three distinct groups of JA3 cell variants to different stimuli showed that all produced interleukin 2 in response to A23187 calcium ionophore plus phorbol 12-myristate 13-acetate. The first group of variants (T3^- Ti^-) did not respond to stimulation with anti-T3, anti-Ti, or anti-T44 mAbs. Eight of 9 did not respond to phytohemagglutinin either; however, all responded to appropriate stimulatory combinations of anti-T11 mAbs (and to calcium ionophore). The second group of variants (T3^-, Ti^-, T44^-, T11⁺), similar to the first group, did not respond to anti-T3, anti-Ti, anti-T44 mAbs, and phytohemagglutinin, but they were fully responsive to anti-T11 mAb. The last group of variants (lacking all the T-cell-specific surface antigens) only responded to calcium ionophore A23187.