['lizbeth]

We, the Her2 3+ are no longer eligible for these particular vaccine trials - but the following article helps explain how the vaccines work.

AE37 is part of the intracellular domain of the HER2 oncogene, while NeuVax, or E75, is part of the extracellular domain of HER2. AE37 is a MHC Class II molecule peptide vaccine, while NeuVax is a MHC Class I peptide vaccine. A MHC Class I vaccine, such as NeuVax, will stimulate CD8+ T Cells, called killer T cells, while they don't stimulate CD4+ T cells, or helper cells, at all.AE37, an MHC Class II molecule peptide vaccine, stimulates CD4+ T cells, often called the Generals, while charging the CD8+ T cells, sometimes called the troops, into a full battle against recurrence of cancer. AE37 is referred to by MD Anderson researchers as a second generation vaccine, with NeuVax being the first generation. AE37 is the most potent peptide vaccine ever researched, and this vaccine is the first to exhibit such strong potency absent of an adjuvant, as COL George Peoples and his group have noted in peer review papers plus abstracts presented at ASCO. See here. However, the main key separating AE37 from other vaccines is the Antigen Express Ii-Key hybrid technology.

Antigen Express' Ii-Key Hybrid technology platform entails the modification of fragments of antigens to increase their potency in stimulating critical members of the immune response, known as CD4+ T helper cells. Incorporating the Ii-Key modification along with tumor-associated antigens can greatly enhance the immune system's ability to recognize and destroy cancer cells bearing any of the targeted antigens as well as increasing immunological memory. Ii-Key bypasses the need for intracellular cell degradation and processing, ensuring any payload attached to the Ii-Key protein will be delivered directly for activation of the immune Generals, CD4+ T cells.
During a recent investor conference call, featuring the Scientific Advisory Board of Antigen Express, Dr. Elizabeth Mittendorf, from MD Anderson and the PI for the AE37 Phase IIb study, explained the following regarding the Ii-Key hybrid technology and AE37,
AE37 is not actually the endogenous peptide, that peptide is known as AE36. By itself, AE36 is not as immunogenic as we'd like it to be, so the scientists at Antigen Express have added this four amino acid sequence, LRMK, which is Ii-Key, onto the beginning of AE36 which makes it about 250% more potent as a vaccine. (Ii-Key hybrid + AE36 = AE37).