The Immune System

The cellular arm of the immune system is critical in protecting us against malignant cells that develop into deadly, metastatic cancers. The immune system is able to distinguish between normal cells and cancerous or virus infected cells by monitoring a molecule on the cell surface called the major histocompatibilty complex (MHC) class I. The MHC molecule contains a small protein fragment referred to as a peptide which, in combination with the MHC molecule, is able to stimulate the killer T-cells of the immune system. This peptide fragment is derived from the degradation of cellular proteins within the cytoplasm of the cell by the proteasome enzyme complex. These peptides are transported into the sub-cellular endoplasmic reticulum (ER) by transporters associated with antigen processing (TAP). Inside the ER peptides combine with other proteins to form functional MHC class I (MHC plus peptide). The functional MHC is transported to the surface of the cell where the functional MHC complex is presented to the immune system. Functional MHC generated from normal peptides within normal cells do not stimulate the killer T-cells of the immune system. However, if the peptide fragments are not normal because they were generated from viral proteins inside an infected cell (viral antigens) or from proteins made exclusively by cancerous cells (tumor antigens) then stimulation of killer T-cells occurs. The killer cells then multiply and kill the abnormal virus infected cell or cancerous cells.

TapImmune's TAP Technology

TapImmune’s vaccine technology is based on modulating the activity of the antigen processing machinery (APM) to increase effective presentation of antigens to the immune system. Transporters associated with antigen processing (TAP) play a major role in the antigen processing pathway by supplying suitable antigenic peptides to the MHC class I complex. Nearly all cell types display MHC class I antigen on their surface and provide the information to the immune system. The immune system uses this information to selectively destroy cancerous cells or those infected with pathogens. When a virus infects a cell, the viral protein components are degraded by the proteasome into smaller peptide components; TAP then facilitates the binding of the foreign peptides of viral origin to the MHC class I complex and these are subsequently display on the infected cell’s surface. Cytotoxic T-Cells recognize foreign peptides bound to the MHC class I antigen on the cell surface and destroy infected cells to prevent the spread of this infection