Evolutionary immunology: Early vertebrates reveal diverse immune recognition strategies

Abstract

Adaptive immune responses in most vertebrates (the gnathostomes: jawed fishes, amphibians, reptiles, birds and mammals) are mediated by lymphocyte-associated antigen receptors encoded by rearranging genes—immunoglobulin (Ig) on B cells and T-cell receptors on T cells. These hypervariable recognition molecules share commonality in their immunoglobulin superfamily (IgSF) domains and the germ-line organization of their rearranging gene elements.