Book Review:
Group Immunity Systems

 "From Bacteria to Belief: Immunity and Security by Dr Luis P. Villarreal, UC Irvine
in "Natural Security, A Darwinian Approach to a Dangerous World"
edited by by Raphael D Sagarin and Terence Taylor

Fractal Julia Design (creative digit image)

I attended a guest lecture by Dr Luis Villarreal, University of California, Irvine, given at the University of Washington . Dr Villarreal gave a very interesting talk about viruses, which got me interested in reading some of his work on the role of viral evolution in life.

Dr Villarreal's work appears in,  "Natural Security, A Darwinian Approach to a Dangerous World" Edited by Raphael D Sagarin and Terence Taylor.  The book discusses applications of security systems which exist in  evolutionary biology,  to solve security based problems in the risky world that we humans have to deal with.  In this blog post I discuss Dr Villarreal's article, in which he discusses immunity systems.  

Dr Villarreal develops his concept of group immunity based on bacterial models, discussing the colonization of genetic parasites such as viruses.  Systems bind individual units to the group using a "carrot or stick" approach to enforce group identity.   His model employs the term Addiction Model for this approach.  This model uses the term "antitoxin" for protective aspects of the system which draw and retain members, and "toxin" for aspects which are destructive or harmful to nonmembers or members who violate the group identity system rules. Together these aspects constitute a security system which is the basis for his discussion.

Biological based concepts are extended to higher level human biological models by asking how we identify members of a group, how we identify self versus foreign entities and how we respond to threats. Human cognitive sensory systems using visual or pheromone based cues are employed.   

Dr Villarreal tackles the very difficult topic of death of the individual for the good of the whole in the context of programmed cell death (apoptosis) where many cells must die in the process of developing a specific specialized tissue, giving specific biological-based examples.   He discusses the issue of genetic parasites which create an addiction state within a host cell whereby the host cannot lose the parasite and still remain alive.  Competition between group identity systems is also important as Dr Villarreal discusses how group identity systems may kill off individual E. Coli cells if one of them is co-opted by another organism.   

Dr Villarreal goes on to discuss adaptive immune systems.  He discusses the worm C. Elegans, whose neural system and ability to protect against endogenous retroviruses is of evolutionary interest.  He discusses the recognition of self versus foreign, the reigning in of an over-reactive immune system that erroneously attacks itself,and the development and training of group identity.  He discusses how evolutionary features of the immune system can be extended to the social activity of humans based on long standing biological evolutionary principles.

Dr Villarreal discusses the creation of a stable group identity system using sensory based systems that may exclude input from non-members.   "Colonization" and imprinting (of language or group identity) is described as a process through which group identity is established and maintained.  The assignment of meanings to words, through language, and the stability of memories are important in such systems.

Dr Villarreal's work is an interesting discussion of the use of evolutionary biology techniques applied to the phylogenetic "tree of life" and one is left wondering the extant implications for the "tree of the garden of good and evil".  

"Natural Security, A Darwinian Approach to a Dangerous World" can be found  through the California Scholarship Online and on Amazon, with interesting contributions from a variety of authors on the topic of natural security and biological based models.