Evolutionary origin of the immune system: A dialogue with Rod Langman

Abstract

The need of a specific defence mechanism against intracellular pathogens is proposed to have arisen very early in evolution, perhaps already in protozoa, e.g. amoebae. The phagocytic machinery of amoebae lends itself as a possible starting point for the evolution of such a mechanism. The hypothetical evolutionary pathway described here has been constructed to demonstrate the feasibility of developing a defence system against pathogens in the amoeba, which bears resemblances to contemporary cell-mediated immunity, and can thus be considered as its ancestor. © 2008 The Author.