Proof of long-term immunological memory in cartilaginous fishes.
Immunological memory provides long-term protection against pathogen re-infection and is the foundation for successful vaccination. We have previously shown an antigen-specific recall response in nurse sharks almost one year after primary exposure. Herein, we extend the time between prime and successful recall to >8 years, the longest period for which immunological memory has been shown in any non-mammalian vertebrate. We confirm that antigen binding is mediated by monomeric IgM and IgNAR, but not pentameric IgM, in both the primary and recall phases. Our inability to find target-binding clones in recombinant VNAR expression libraries suggests that, at least in this instance, antigen-specific memory cells comprise a small fraction of the IgNAR-positive B cells in epigonal and spleen. Further, that the few memory cells present can generate a robust antigen-specific IgNAR titer following re-stimulation. Our results continue to challenge the long-held, but erroneous, belief that the shark adaptive immune system is 'primitive' when compared to that of mammals.
['Eve|Oliver|O|', 'Matz|Hanover|H|', 'Dooley|Helen|H|']
D056704:Adaptive Immunity D000818:Animals D000941:Antigens D005260:Female D029941:Fish Proteins D007075:Immunoglobulin M D007156:Immunologic Memory D011946:Receptors, Antigen D012754:Sharks
Memory Cartilaginous fish Shark IgM IgNAR Antibody