Immune system function has a direct influence on swine growth. Using lipopolysaccharide (LPS) to stimulate the immune system of pigs provides insight on how they handle immunological stress. Several proteins were shown to be part of the liver’s response to LPS. These proteins included heat shock protein (HSP) 60, HSP70, and peroxiredoxin-2. Changes in the abundance of these proteins indicate the extent to which an animal can respond to this immune system stimulation (ISS). Proteins responsible for cellular rescue were found to be increased in abundance in pigs with stimulated immune systems.