Challenging Immune Diversity Dogma

Science's STKE  03 Jan 2006:
Vol. 2006, Issue 316, pp. tw459
DOI: 10.1126/stke.3162006tw459

The adaptive immune system has been thought to be confined to the realm of jawed vertebrates, where somatic mechanisms of genetic variation have evolved to generate immune receptors in great diversity that are clonally dispersed among its lymphocytes. However, recently, jawless fish have been shown to be able to generate diversity among immunelike receptors, and indeed, some invertebrates produce diverse immunoglobulin-like molecules. Extending their original discovery of variable lymphocyte receptors (VLRs) in the sea lamprey, Alder et al. now provide information on the form, function, and potential extent of somatic genetic diversity in this system. Leucine-rich repeats (LRRs) are randomly selected from a large bank of LRR modules by a sequential mechanism of rearrangement, so that the estimated diversity of VLRs may rival that of mammalian immune receptors. Furthermore, serial immunization of lampreys was found to elicit the responses expected in a developing adaptive immune response to an antigen.

M. N. Alder, I. B. Rogozin, L. M. Iyer, G. V. Glazko, M. D. Cooper, Z. Pancer, Diversity and function of adaptive immune receptors in a jawless vertebrate. Science 310, 1970-1973 (2005). [Abstract] [Full Text]