XXXX -induced @entity204 of immune cells: its mechanisms and consequences.

@entity39 @entity5 @entity2874 @entity12 @entity204
@entity12 is a @entity204 -inducing as well as pro-inflammatory molecule. The seemingly opposing consequences of Fas/ @entity12 interactions appear to be dependent on the context of the @entity5 or tissue microenvironment. The term 'contextual' has been coined to describe cellular and molecular events that may be opposing, yet are mediated by the engagement of the same receptor-ligand pair. Because Fas is one of the @entity204 -inducing receptors, its ligand is dangerous. Hence, the availability of @entity12 for cross-linking of the receptor has to be extremely carefully regulated. Different levels of control appear to exist, some involving cell membrane-associated MMPs and others depending on cytokines released from neighboring cells. In @entity5 , which shape their microenvironment to make it unwelcome to immune effector cells, @entity12 is used to kill infiltrating cells without damage to the @entity5 , which develops multiple means of hiding/inhibiting the @entity204 pathway. On the other hand, in situations provoking inflammatory responses such as allograft rejection, infection, and tissue @entity39 , @entity12 assumes the role of attractant for inflammatory cells. In these situations, @entity12 acts in conjunction with other cytokines, and its effects might be modified in the context of unfolding events. When put in the context of biologic interactions that take place at the @entity5 site, the Fas/ @entity12 pathway emerges as a molecular mechanism, which contributes to immune privilege and @entity5 escape, but which can also enhance anti- @entity5 inflammatory responses. @entity12 , like many cytokines, is pleiotropic. It is also worth bearing in mind that other molecular players, including the other known members of the @entity2874 family, almost certainly participate in establishing immune privilege status of @entity5 . While a broad body of new information has contributed to clarifying the dual role of @entity12 in the @entity5 biology, much remains to be learned about molecular mechanisms that control its effects in the @entity5 and in normal tissues.
