"Certainly, pleiotropicity and redundancy of molecules involved in pathways of the innate immune system must be respected. In fact, cascades of proteins that serve as precursor molecules with active and inactive forms have evolutionary advantages in eukaryotic development. These protein cascades provide sufficient flexibility and redundancy that mutations in these regulatory pathways may alter the expression of multiple enzyme systems. These mutations in cascades of regulatory proteins could be tolerated without the loss of entire organisms viability.
This permits phenotypic variation in enzyme systems within populations of metazoan life forms. These systems provide a substrate for what is termed evolvability within complex multicellular organisms. The more complex and the greater the need for longevity in vertebrate evolution, the more common and multifunctional these protein cascades become. This evolutionoriented scenario makes all attempts to effectively block the activation of the innate immune system so difficult ..."