If we can image therapeutic cytokine as a typical baseball, it is fairly toxic when given to a patient systemically. It stimulates patient’s immune cells to become hyperactive and have non-discriminatory immune responses.
So we covered parts of baseball that stimulate immune cells with baseball glove. This is pro-cytokine which doesn’t function as is.
We take advantage of hyper-active enzymes in tumor tissue to pull ‘pro-cytokine’ baseball out of the glove (proteolytic separation of functional cytokine from inactive pro-cytokine) , making it fully functional to stimulate immune cells in proximity.
So we covered parts of baseball that stimulate immune cells with baseball glove. This is pro-cytokine which doesn’t function as is.
Furthermore, we have engineered cytokines into Zytokines making them ‘sticky’ like tennis ball.
- Conventional cytokines easily diffuse away from tumor tissue
- Zytokines are ideally designed to accumulate in the tumor tissues which almost always have dense network of extra cellular matrix creating high local concentration of potent therapeutic cytokines