The evolution of non-classical MHC class I genes and T-cell receptor repertoires in salamanders.

Adaptive immunity relies on the diverse lymphocyte receptors and antibodies generated anew during the individual’s life. However, an efficient adaptive immune response requires a large pool of lymphocytes and takes time to mount, which poses a serious challenge for fish and amphibians that hatch at a very small size and continue their development in the pathogen-rich aquatic environment. It has been hypothesized that the use of the so-called unconventional lymphocytes that carry receptors of limited diversity would be an efficient solution in the face of such constraints. The benefits of such a system may be particularly pronounced in amphibians that undergo metamorphosis, a dramatic event that profoundly remodels their immune system. Indeed, research on the frog Xenopus demonstrated that the larval immunity depends crucially on unconventional T lymphocytes that recognise pathogen molecules presented on the surface of other cells by the so-called nonclassical Major Histocompatibility Complex class I proteins (MHC-Ib).

In this project, we take advantage of diverse developmental modes and considerable phylogenetic diversity of salamanders to test key hypotheses about the evolution of MHC-Ib genes and T-cell receptor (TCR) repertoires. We will identify and characterize MHC-Ib genes in salamanders, estimate the number of independent origins and losses of MHC-Ib genes through the salamander evolution, and date these events. We will also investigate the expression of MHC-Ib and the diversity of TCR repertoires throughout the individual’s life. Overall, the project will provide information crucial for the understanding of the evolution at the interface between innate and adaptive immunity.

PSP Project No: K/NCN/000002

PI: Prof. dr hab. Wiesław Babik

Project duration: 28.11.2022 - 27.11.2026

Funder: National Science Centre in Poland (NCN)