Immunopathology

Semaphorins are originally identified as axonal guidance factors in the developing nervous system in 1990s. Cumulative evidence suggests that semaphorins also play important roles in the other systems, including organogenesis, vascularization, angiogenesis and the progression of cancers. In 2000, our research groups have identified a class IV semaphorin, CD100/Sema4D, as an immune-regulatory molecule expressed on immune cells. To date, it becomes clear that some other semaphorins (Sema3A, Sema4A, Sema4B, Sema4G, Sema4F, Sema6A, Sema6B, Sema6D, Sema7A) are also expressed in the immune system and play non-redundant roles in immune responses. These semaphorins are now called as ‘immune semaphorins’ (Fig.1). Immune semaphorins are involved in various phases of immune responses including activation phase, differentiation phase and effecter phase (Fig.2). We work on the molecular mechanisms underlying regulation of immune responses by immune semaphorins.