Evolutionary Immunology: A boost to immunity from nurse sharks

Abstract

A study of the nurse shark has revealed a type of rearranging gene that has yet to be seen in mammals; it encodes a secreted 'new antigen receptor' which, unlike shark immunoglobulin, revels in somatic hypermutation.

cDNA cloning of the immunoglobulin heavy chain genes in banded houndshark Triakis scyllium

“…A novel type of immunoglobulin that is composed of only 2 H chains, lacking light (L) chains, was discovered in nurse shark Ginglymostoma cirratum in 1995 [9,10]. Because of its unique structure, it was named new antigen receptor (IgNAR).…”

Antibacterial Proteins and Peptides in Nurse Shark (<em>Ginglymostoma Cirratum</em>) Peripheral Blood Leukocytes

“…This basal animal is strategically placed in the phylogenetic lineage and is a good model to study unresolved questions regarding antimicrobial peptides in primitive vertebrates. The nurse shark's natural antibodies, spontaneous cytotoxicity, and complement have been studied, and are believed to work in concert to form an immunosurveillance system seeking out new antigens (Rudikoff et al 1970;Clem et al 1982;Pettey et al 1983;Smith et al 1986;Flajnik 1994;Parham 1995). In addition, innate system components such as antibacterial proteins/peptides and other antimicrobial substances may form the basis of innate immunity necessary to maintain a healthy animal, particularly during times of stress.…”