The immune system is often regarded only as a defense, keeping us free from harmful microbes. What if our immune system today is functioning not very differently than it did in the pre-Fall world? A better understanding of its purpose may emerge if we reframe it (1) via design-based system analysis, and (2) in light of contemporary microbiome research findings. Microbiome research reveals far more harmony than antagonism in organism-microbiome relationships. Systems analysis indicates one design certainty: An interface system must coordinate independent entities to harmonize together. Therefore, design-based creationist research would look for, and find, human-designed interface systems possessing nearly indistinguishable counterpart elements as found in immune systems. When dynamic host system-to-microbe relationships are understood in light of design analysis, the clear properties of a rich, multifunctional "microbe interface system" (MIS) are evident—which is the key link associating us to trillions of microbes in a mutually beneficial symbiotic relationship. Concentrating on the presence of interface-distinctive elements could better characterize what may misleadingly be labeled an "immune" system.