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Review
. 2015 Jul 31;4(3):512-24.
doi: 10.3390/biology4030512.

Antibody Affinity Maturation in Fishes-Our Current Understanding

Brad G Magor  1
Affiliations
Review

Antibody Affinity Maturation in Fishes-Our Current Understanding

Brad G Magor. Biology (Basel). .

Abstract

It has long been believed that fish lack antibody affinity maturation, in part because they were thought to lack germinal centers. Recent research done on sharks and bony fishes indicates that these early vertebrates are able to affinity mature their antibodies. This article reviews the functionality of the fish homologue of the immunoglobulin (Ig) mutator enzyme activation-induced cytidine deaminase (AID). We also consider the protein and molecular evidence for Ig somatic hypermutation and antibody affinity maturation. In the context of recent evidence for a putative proto-germinal center in fishes we propose some possible reasons that observed affinity maturation in fishes often seems lacking and propose future work that might shed further light on this process in fishes.

Keywords: AID; Aicda; activation-induced cytidine deaminase; affinity maturation; antibody; evolution; fishes; germinal center; somatic hypermutation.

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Figures

Figure 1
Figure 1
Schematic of outcomes of activation induced cytidine deaminase (AID) mediated cytidine deaminations in immunoglobulin genes. AID targets cytidines within the RGYW hotspot motif. UNG—Uracil-DNA-glycosylase; APE—apurinic/apyrimidinic endonuclease.
Figure 2
Figure 2
AID expressing cells in channel catfish spleen. (a) In situ hybridization with AID anti-sense probe (green) under excitation for FITC. Melanomacrophages autofluoresce yellow; (b) UV excitation elicits orange/brown autofluorescence of only melanomacrophages (and RBCs in blue). Methods are as described in [28].
See this image and copyright information in PMC

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