Cancer research has demonstrated that immunization with homologous xenogeneic proteins (such as vaccines contaminated with animal proteins that resemble human proteins) results in autoimmunity. Bioinformatics analysis demonstrates that animal proteins have occasional amino acid differences compared to equivalent human proteins. For this purpose we used Uniprot and BLASTP. We found homology to human GP2 (Bos taurus 77%, Sus scrofa 76%, Cavia porcellus 72% Gallus gallus 43%), homology to human tyrosinase (Bos taurus 87%, Sus scrofa 90%, Cavia porcellus 85%, Gallus gallus 73%), homology to human GP100 (Bos taurus 77%, Sus scrofa 81%, Cavia porcellus 77%, Gallus gallus 42%) and highlight the occasional amino acid differences. Mutated human protein epitopes can be identical to animal protein derived epitopes. Low affinity self reactive T cells suited for detection of mutated human epitopes will be activated by animal derived epitopes. CD8+ T cells involved in numerous autoimmune disorders express the CCR4 skin homing receptor. This is evidence that the site of priming was the skin. This is consistent with subcutaneous or intramuscular injection of animal protein contaminated vaccines. The above findings add to the growing evidence of vaccines inducing autoimmune diseases. Autoantibody and autoreactive T cell levels can vary from person to person. Not everyone will develop overt disease. For every case of diagnosed autoimmune disease, there are numerous subclinical cases. These subclinical diseases could shave decades off your life. So “rare” diagnosed vaccine adverse events are the tip of the iceberg.