Accumulation of passively transferred primed T cells independently of their antigen specificity following central nervous system trauma

The central nervous system (CNS) enjoys a unique relationship with the immune system. Under non-pathological conditions, T cells move through the CNS but do not accumulate there. CNS trauma has been shown to trigger a response to CNS self-antigens such as myelin basic protein (MBP). Here, we examined whether the injured CNS tissue undergoes changes that permit T cell accumulation. We found that injury to CNS white matter, such as the optic nerve, led to a transiently increased accumulation of T cells (between days 3 and 21). In Lewis rats with unilaterally injured optic nerves, systemic administration of passively transferred T cells recognizing either self- antigen (MBP) or non-self-antigen (ovalbumin) resulted in accumulation of the T cells in injured optic nerve, irrespective of their antigenic specificity. The effect of the T cells on the damaged nerve, the lack of selectivity in T cell accumulation and the mechanism underlying non-selective accumulation are discussed.