Adaptive Immunity in Reptiles: Conventional Components but Unconventional Strategies

Recent studies have established that the innate immune system of reptiles is broad and robust, but the question remains: What role does the reptilian adaptive immune system play? Conventionally, adaptive immunity is described as involving T and B lymphocytes that display variable receptors, is highly specific, improves over the course of the response, and produces a memory response. While reptiles do have B and T lymphocytes that utilize variable receptors, their adaptive response is relatively non-specific, generates a prolonged antibody response, and does not produce a typical memory response. This alternative adaptive strategy may allow reptiles to produce a broad adaptive response that complements a strong innate system. Further studies into reptile adaptive immunity cannot only clarify outstanding questions on the reptilian immune system but can shed light on a number of important immunological concepts, including the evolution of the immune system and adaptive immune responses that take place outside of germinal centers.