The Complex Science of Cyberdefense: Computer Immunology

Threats are ubiquitous in complex systems: biology is rife with viruses, parasites, and bacteria; social networks abound with bullies; and international relations are stymied by rogue nations. In the second of three lectures, Stephanie Forrest proposes that understanding how complex systems generally resolve threats might suggest ways to address threats in cyberspace. Observing that biological defense systems solve essentially the same problem, she then explains how concepts from immunology are being adapted for the computational realm, and considers how the cyber world’s interrelationships with economics, social interactions, and politics may complicate the future of cyberdefense.


Immunology is a branch of biology that covers the study of immune systems in all organisms.

Immunology charts, measures, and contextualizes the physiological functioning of the immune system in states of both health and diseases; malfunctions of the immune system in immunological disorders (such as autoimmune diseases, hypersensitivities, immune deficiency, and transplant rejection). Immunology describes the physical, chemical, and physiological characteristics of the components of the immune system in vitro, in situ, and in vivo.

Immunology has applications in numerous disciplines of medicine, particularly in the fields of organ transplantation, oncology, virology, bacteriology, parasitology, psychiatry, and dermatology.

History of Immunology

It was the Russian biologist Ilya Ilyich Mechnikov who boosted studies on immunology, and received the Nobel Prize in 1908 for his work. He jabbed the thorn of a rose on a starfish and noted that, 24 hours later, cells were surrounding the tip. It was an active response of the body, trying to maintain its integrity. It was Mechnikov who first observed the phenomenon of phagocytosis, in which the body defends itself against a foreign body, and coined the term.


In an organism’s immune system, phagocytosis is a major mechanism used to remove pathogens and cell debris.

In cell biology, phagocytosis is the process by which a cell engulfs a solid particle to form an internal compartment known as a phagosome. Phagocytosis is involved in the acquisition of nutrients for some types of cells. The process is homologous to eating at the level of single-celled organisms. In multicellular animals, the process of phagocytosis has been adapted to eliminate debris and pathogens from the body.