Adaptive immunity in jawless fish

The jawless vertebrates like lamprey and hagfish have an adaptive immunity which is very similar to the one of the jawed vertebrates. There is an T-/B-Cell like lymphocyte lineage. Therefore, these cells are called lymphocyte like cells (LLC). They are distinguished through the expressed receptor into the three subclasses:

• LLCA (equivalent to α/β T cells)
• LLCC (equivalent to γ/δ T cells)
• LLCB (equivalent to B cells)

Antigen receptors

The expressed receptor is the so-called variable lymphocyte receptor (VLR), which belongs to the leucine-rich repeat (LRR) family.

References

• Kasamatsu, J. (2013). Evolution of innate and adaptive immune systems in jawless vertebrates. Microbiology and immunology 57, 1-12.
• Guo, P. et al. (2009). Dual nature of the adaptive immune system in lampreys. Nature 459, 796-801.
• Kishishita, N., and Nagawa, F. (2014). Evolution of adaptive immunity: implications of a third lymphocyte lineage in lampreys. BioEssays : news and reviews in molecular, cellular and developmental biology 36, 244-250.
• Saha, N.R. et. Al. (2010). Evolution of adaptive immune recognition in jawless vertebrates. Seminars in immunology 22, 25-33.