TAP and Breast Cancer

Wilson says with any vaccine, there are two requirements needed to create a good immune response: 1) stimulate the cytotoxic lymphocyte (Class 1 pathway) and 2) stimulate the pathway that stimulates the T helper cells (Class 2 pathway), which gives a long-lasting immune response. The failure to satisfy both of these requirements is one of the reasons other breast cancer vaccines haven't progressed.



For breast cancer, we are developing a unique multi-component vaccine that stimulates the Class 2 pathway (CD4 helper cells) for a prolonged immune response and the Class 1 pathway (CD8 cytotoxic T cells) to activate killer T-cells that will infiltrate and destroy tumor cells. The HER2/neu vaccines that had been tested in the past either do not stimulate sufficient cytotoxic T-cell response on the Class I pathway or they do not give a long-lasting effect. I realized that we have the capability here with the Mayo technology plus TAP of creating good responses on both sides of the immune system required for a good vaccine. It is a very innovative, creative and exciting approach.



TapImmune President and CFO Denis Corin agrees.I think there are a lot of vaccine candidates that have gone through the mill and probably failed at Phase 2 or Phase 3 predominantly because the immune recognition and immune stimulation hasn't been as effective as they needed it to be to come up with an end-level product. TAP is elegantly simple and we believe applicable across multiple types of cancers.


In the overall vision of the use of cancer vaccines, the ultimate goal is to have vaccines that can be used prophylactically at the earliest detection of pre-cancerous conditions like DCIS,Corin continues. It is thought that the more advanced the cancer, the lower the TAP levels will be. TAP may be applicable to all stages of cancer if we consider experiments that treated smallpox, augmenting the normal levels of TAP and making a smallpox vaccine fully 100 to 1,000-fold more potent.



The Science

The immune system distinguishes normal and cancerous (or virus-infected) cells by monitoring major histocompatibility complex (MHC) class I, a molecule on the cell's surface. Nearly all cell types display MHC class I antigen on their surface, continually providing information to the immune system. The MHC molecule, which contains small protein fragments (peptides), cycles to the surface of the cell to present foreign antigens to the cellular immune system, thereby activating the cytotoxic T-cells to kill virus-infected or cancerous cells.

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