Immune function testing by the Cellular NK-Test
Beside chemotherapeutic or hormonal therapies that are directed against the malignant cells, certain alternative treatment options have the aim to stimulate the body’s immune cells and to augment the immune system in fighting the tumor. Numerous immuno-activating agents are available, e.g.
- Botanicals (e.g. Mistletoe, Biobran, etc.
- Thymus extracts: (e.g. Thymosin, Thymoject)
- Cytokines (e.g. interleukin 2)
All these agents have a potent propensity to stimulate and activate Natural Killer (NK) cells. NK-cells belong to the lymphocytes and play a very important role in the early defense of the immune system against viruses, bacteria and tumor cells. Activation of the NK-cells is regulated by a subtle balance between positive and negative signals. Surface receptors on the NK-cells transmit either activating or inhibiting signals into the cell.
In tumor patients, NK-cells are often diminished in numbers and restricted in functionality. The extent of this impaired immune function correlates with disease progression and time of survival. Enhancement of the immune function is therefore a important therapeutic goal.
The mere number of NK cells is not sufficient to assess the functionality of this important defense system. An in vitro assay has been established in our lab to measure the capability of a patient’s immune cells to destroy tumor cells. For this, lymphocytes are isolated from a patients blood sample and incubated together with dye-labeled tumor-cells. Lysis of the tumor cells by the immune cells liberates the dye and can be quantified in the culture supernatant.
The amount of liberated dye reflects the actual, spontaneous NK-cell activity (see Figure below). Beside the determination of the spontaneous NK-cell activity, we can determine if the immune cells are susceptible to be stimulated by immuno-acitvation therapy. The percentage increase of tumor cell lysis compared to the spontaneous NK-cell activity is a degree of capability of the NK-cells to be activated. This allows the estimation of how promising a immune-stimulative therapy will be. During the course of such a therapy, treatment success could thereby be monitored with the assay.
Principle of Cellular NK Testing
Agents which can be tested in the Cellular NK-Test:
Basically, every substance claimed to activate the NK-cells could be used in the assay. We routinely use thymus extracts, mistletoe extracts and interleukin 2. Other agents could be tested upon request. In such instances, please provide a sample of the agent to be tested.
