Couldn't we be immunized against cancer? This sounds like a dream, but is in fact a thoroughly realistic research goal. American researchers have now taken an important step forward in the development of a cancer vaccine. Their fully synthetic vaccine candidate consists of an oligosaccharide, a peptide, and a lipopeptide.
How can the immune system be made to attack tumor cells, which - though degenerate - are part of the body? The immune system must be presented with a component characteristic of tumor cells in the form of a vaccine, so that it can form antibodies against this antigen, as it is called. If tumor cells then appear later, the antibodies recognize the antigen and bind to it, marking it as an enemy that must be destroyed. Among the differences between tumor cells and healthy cells is an abnormally high amount of certain oligosaccharides, which are involved in the formation of metastases. One of these saccharides would be a suitable antigen. However, attempts to implement saccharides as the basis for a vaccine have thus far failed; unfortunately, carbohydrates are able to activate B-lymphocytes, but not T-lymphocytes. For successful immunization, the cooperation of both types of cells is needed. It is helpful to couple the sugar to a foreign carrier protein, but this is a poorly controllable reaction whose products can also trigger undesired immunological effects.