Immune cell atlas reveals the molecular characteristics and evolution of adaptive immune in cartilaginous fish

The emergence BCR, TCR and MHC dependent adaptive immune system in cartilaginous fish is a key evolution event. However, the gene expression characteristics and regulation mechanism of immune cells in cartilaginous fish remain elusive. In this project, by performing immune cell atlas of bamboo shark, zebrafish and Chinese tongue sole, we systematically analyzed immune system architecture and gene expression signatures of both cartilaginous fish and bony fish. We also trace the evolution of immune cells specializations by phylogenetic integration of immune cells from three fishes. Additionally, systematic comparison of B and T cells between bamboo shark and teleost fish (zebrafish and Chinese tongue sole) revealed the similarity and diversity of adaptive immunity in cartilaginous fish. Overall, our study provides insights into the origin and evolution of adaptive immunity.