Response to Cohn: The immune system rejects the harmful, protects the useful and neglects the rest of microorganisms.

The immune system is seen as a guardian of tissue integrity. It would analyse the extent and quality of damage and respond adequately. If no ill effects were found, the system would ignore disturbance, but if beneficial effects were found, it could protect certain microorganisms (establishing commensalism), perhaps via regulatory cells. The Integrity hypothesis proposes three basic groups of intercellular signals for cells of all tissues and assumes that they govern communication between dendritic cells, T cells and B cells. Signal-1 would be the main information source resulting with generation of intracellular mediators that are bound to travel into the nucleus to achieve reaction. Signal-2 represents the generation of additional signal transducers representing a modifier at the level of cytosol. And, signal-3 would be a modifier at nuclear level, perhaps guarding accessibility to chromosome or genetic locus.