Figure 2

Summary of expected CD4+ cell differentiation in fish. Expected Milieu of cytokines (denoted by colored symbols) influencing CD4+ T cell differentiation with (IL-12) causing naïve CD4 cells ultimately differentiated into Th-1 cells to get rid of invading intracellular pathogen i.e. Bacteria, Viruses. Similarly, IL-2, IL-2L, IL-13A, IL-13B brings forth differentiation of Th2 cells in response to extracellular parasitic infectious agent. Differentiated Th-17 cells; autoimmunity and I-Treg cells; homeostasis are produced in response to cytokines IL-23, IL-21, IL-6 and IL-2, IL-2L respectively with TGF-ß1as a common precursor.