Several types of cancer immunotherapies are currently in use and being tested. The advantage of immunotherapy is that it involves a more specific response to the tumor cell and thus reduces the amount of side effects patients currently face with the use of chemotherapy and radiation. Some examples of immunotherapies being studied are given below. Keep in mind that immunotherapies are a form a passive immunization. Cancer vaccines will be discussed under the vaccine section.
Manipulation of co-stimulatory signals involves transfecting irradiated melanoma cells with the gene encoding B7 ligand invitro. This causes CTL precursors to differentiate to effector CTLs. Upon exposure to unaltered malignant melanoma cells, effector CTLs are mobilized immediately, resulting in a much more effective immune response to the tumor cells.
Enhancement of Antigen Presenting Cell Activity- This involves transfecting tumor cells with the gene encoding GM-CSF invitro. When these tumor cells are re-infected into the patient, they secrete GM-CSF, enhancing the differentiation and activation of host antigen-presenting cells, which enhances presentation of tumor antigens to T-helper and CTL cells.
Invitro-Activated LAK Cells - Involves sensitizing lymphocytes invitro with high concentrations of IL-2. This results in large numbers of activated lymphoid cells that can kill fresh tumor cells but not normal cells. However, the high levels of IL-2 required for LAK-cell activity results in a number of side effects.