Data from: Complete loss of the MHC II pathway in an anglerfish, Lophius piscatorius

Genome studies in fish provide evidence for the adaptability of the
vertebrate immune system, revealing alternative immune strategies. The
reported absence of the major compatibility complex (MHC) class II pathway
components in certain species of pipefish (genus Syngnathus) and cod-like
fishes (order Gadiformes) is of particular interest. The MHC II pathway is
responsible for immunization and defence against extracellular threats
through the presentation of exogenous peptides to T helper cells. Here we
demonstrate the absence of all genes encoding MHC II components (CD4, CD74
A/B, and both classical and non-classical MHC II α/β) in the genome of an
anglerfish, Lophius piscatorius, indicating loss of the MHC II pathway. In
contrast, it has previously been reported that another anglerfish,
Antennarius striatus, retains all MHC II genes, placing the loss of MHC II
in the Lophius clade to their most recent common ancestor. In the three
taxa where MHC II loss has occurred, the gene loss has been restricted to
four or five core MHC II components, suggesting that, in teleosts, only
these genes have functions that are restricted to the MHC II pathway.