[Methods for increasing the immunogenicity of vaccines].

In the past years, enormous efforts have been undertaken to develop vaccine strategies against cancer. The aim is to have the immune system generate what are called killer cells that can specifically recognize the tumor. The surface of tumor cells contains MHC/HLA antigens which present short-chain peptides of tumor specific antigens. A large number of these oligopeptide antigens have been characterized in recent years. They are now available for use as tumor-specific vaccines. The problem is, however, that the immune response of producing T killer cells is very inefficient when these oligopeptide antigens are injected. As the physiological function of these killer cells virus-infected cells, a process associated with substantial tissue damage, the immune system has learned to use these killer cells with reticence over the course of evolution, in other words, when the life of the host is threatened. This does not happen until pathogens start to spread via lymphogenous or hematogenous pathways. And then it takes a certain amount of time after the invader is present for replication to take place. Since the oligopeptide antigens used as vaccines have a very short half-life in the tissue, not enough of them get to the lymph nodes and stay there for enough time to efficiently induce an immune response. Using a mouse model, we were able to show that the efficiency of the vaccine can be increased a million-fold by directly injecting the vaccine into a lymph node or the spleen which imitates lymphogenous or hematogenous spread. The efficiency of the "inactivated vaccine" can be enhanced even more by continuous administration of the vaccine over several days, simulating an especially dangerous virus replication. The evidence gathered in this mouse model was transferred to a clinical trial. The melanoma-specific inactivated vaccine is infused directly into a lymph node of tumor patients. The infusion is continued for several days. Booster vaccines are given every two weeks.