Flow cytometric analysis of infiltrating cells in the peripheral nerves inexperimental allergic neuritis

Experimental autoimmune neuritis (EAN) is an animal model that shares clini cal, pathological and electrophysiological features with the human disease Guillain-Barre syndrome (GBS). In this study, we isolated and characterized by fluorescent activated cell sorter (FACS) phenotype of the inflammatory cells infiltrating cauda equina (CE) of Lewis rats at the active stage of t he disease. We found that at this stage of EAN macrophages (M phi) and alph a beta T cells were two major populations isolated from CE. We also found t hat among total cell population isolated from CE, gamma delta T and NK cell s composed two small but distinct populations, while B cells were negligibl e. We characterized phenotype of alpha beta T cells in CE as CD45RC(+)CD8() (activated cytotoxic lymphocytes) and CD45RC(-)CD4(+) (memory Th cells). The phenotype of gamma delta T cells was found to be consisted of only CD45 RC(+)CD8(+) cells. Both alpha beta and gamma delta T cells in CE expressed a higher level of CD25, CD44 and CD54 activation markers compared to the ot her tissues. Immunohistochemistry demonstrated that gamma delta T cells exi sted apart from the intense cellular infiltrate. This is the first report o n the isolation and FAGS analysis of CE-infiltrating cells, contributing a new and alternative approach to study the inflammatory lesions in EAN. We c onclude that both alpha beta and gamma delta T cells have a unique activati on/inflammatory phenotype required to traffic through and be retained in th e peripheral nerves during EAN. (C) 2000 Elsevier Science BN. All rights re served.