In my host lab at CEES the ancient teleost Atlantic cod (Gadus morhua) was employed as model animal to conduct evolutionary and comparative immunological study. This particular animal has unique genome sequence with absent of major histocompatibility complex (MHC) II family receptors, which are crucial immune molecules in adaptive immunity of jawed vertebrates. Moreover, specific gene expansions suggest that the Atlantic cod immune system has evolved alternative strategies to cope with this loss (e.g. via extraordinarily diversified TLRs). Nevertheless, an evolutionary, functional and co-evolutionary understanding of this unique phenomenon is lacking. Thus, the ongoing research project “Functional and comparative immunology of a teleost’s world without MHC II” is really tantalizing to be further carried out.