I wonder if the antibody gene is always-on, if it has any induction/control mechanism(s). If not, I wonder if there would be a noticeable toll on energy levels, or if it would cause molecular crowding in the blood. I wonder if a future version would act more like immunological memory... So expression had a low basal level until ramp-up is needed to overwhelm any antigen that was sensed.
http://mobile.nytimes.com/2015/03/10/health/protection-without-a-vaccine.html