Targeted in vitro and in vivo gene transfer into T Lymphocytes: potential of direct inhibition of allo-immune activation

Transfection of CD3p21 sense and antisense in mouse thyoma cell line (EL4-IL-2) resulted in modulation of mitogen-induced proliferation. The intramuscular injection of CD3p21 sense and antisense plasmid DNA into mice also modulated lymphocyte proliferation and mRNA expression of pro-inflammatory cytokines.These results demonstrate a novel strategy of in vitro and in vivo transfer of p21 gene to T cells using CD3-promoter to achieve targeted inhibition of lymphocyte proliferation and immune activation.Aberrant T lymphocyte proliferation is a key mediator of alloimmune activation in organ transplantation. Therefore, T cells are the key targets for direct transfer of genes that could inhibit their proliferation and alloimmune activation. A number of strategies using either adenoviral or lentiviral vectors linked to mono or bispecific antibodies directed against T cell surface markers/cytokines did not yield the desired results [1-4]. The efficacy of a CD3 promoter-p21 chimeric construct to transfer p21 gene to T lymphocytes was tested. Cyclin kinase inhibitor p21 is a potent inhibitor of lymphocyte proliferation and inflammation [5,6]. Inflammation is realized as one of the key mediators of a number of diseases associated with aberrant cellular proliferation including alloimmune activation and organ transplant rejection. [7-12]. Transfer of genes into T cells remains a critical step to achieve successful therapeutic strategies for such diseases. It is also clear that resting T cells, which make up most of the circulating T-cell pool in vivo, cannot be specifically and efficiently transfected due to the presence of other immune cells in the same milieu. The direct adenoviral and lentiviral vectors mediated gene transfer to T cells was not successful and the modification and coupling of these vectors with antibodies to CD3 and other T cell surface receptors permitted some limited success [1-4,13-16]. Interestingly, expression of cyclins and cyclin-dependent kinases and p