Efficient induction of human CD4+ T cell lines reactive with a self-K-ras-derived peptide in vitro, using a mAb to CD29.

In recent studies, we analyzed effects of a large series of mAbs submitted to T-cell and adhesion structure sections of 6th International Workshop on Human Leukocyte Differentiation Antigens, on proliferative responses of a human CD4+ T cell clone. We found that certain mAbs to CD27, CD28, CD29, CD43 and CD44 markedly restore T cell responsiveness, only in the presence of the natural peptide ligand at low concentrations and even in the absence IL-2. To set up efficient strategies for developing T cell lines and clones reactive with self-peptides in vitro, we stimulated PBMC with a K-ras-derived peptide in the presence of these mAbs and found that: (a) anti-CD29 mAb MAR4 is effective for in vitro expansion of K-ras (residue 3-20)-reactive T cells from PBMC; (b) indeed, DR8 (DRB*0802)-restricted and DR51 (DRB5*0102)-restricted CD4+ T cell clones were established from the T cell lines; (c) MAR4 inhibits anti-CD3-induced apoptosis of PBMC; and (d) MAR4 is effective in enhancing anti-CD3- and antigen-induced proliferative responses of PBMC. Therefore, mAb MAR4 increased efficiency in establishing T cell clones from PBMC, both by suppressing antigen-driven activation-induced cell death and by enhancing the T cell proliferation, only in the presence of TCR/CD3-mediated stimulation. Possible application of MAR4 for establishing self-reactive T cell lines and expanding T cells ex vivo for anti-cancer immunotherapy, is discussed.