The import of peptides into lymphocytes and their effects on the cell cycle

Primary lymphocytes and lymphocytic cell lines are notoriously difficult to transfect. Electroporation is highly disruptive, causing large scale cell death and it is inefficient; between 1% and 10% of the surviving cells express the desired protein. In addition, quiescent primary lymphocytes require partial activation for successful electroporation. We have investigated the cellular import of the third helix of the antennapedia homeodomain protein as an alternative method for introducing peptides into primary lymphocytes and lymphocytic cell lines. We conclude that the peptide is taken up rapidly into the cytoplasm and nucleus of at least 95% of the cells, it is retained for at least 48 hours and it appears to be non-toxic at the concentrations tested. We are using this system to import larger peptides into lymphocytes to investigate their effects on cell cycle control