The invention provides a method for activating a T lymphocyte by contacting the T lymphocyte with a dendritic cell (DC) that presents a telomerase reverse transcriptase (TRT) peptide in the context of an MHC class I or MHC class II molecule. The DC may be pulsed with a TRT polypeptide or may comprise a recombinant polynucleotide encoding a TRT such as hTRT. The invention also provides DCs comprising a recombinant TRT polynucleotide. The methods and compositions of the invention are used in prevention and treatment of cancers and other cell proliferation diseases or conditions.