Immune System

The continuing explosion of knowledge on the immune system has substantial implications for swine health. This contains key concepts, including immune proteins and cell subsets, genetics, microbiome–immune interactions, and vaccine responses. The immune system develops in the fetus, and immune responses begin where microorganisms and/or their products interact with epithelial cells of the mucosa and skin. Pattern recognition receptors, including Toll-like receptors, monitor pathogen-associated molecular patterns and induce different signaling pathways to activate the immune system against infection. Immune system functions require energy, protein, vitamins, and trace minerals. Immune dysfunction or decreased immunocompetence can be due to a variety of factors including stress, malnutrition, and concurrent infections; immaturity or senescence of the immune system may also lead to vaccination failure. If the immune dysfunction occurs at the time of vaccination, the vaccine may fail to induce an adequate immune response.