title: Effect of cold preservation on lymphocyte migration into peripheral nerve allografts in sheep.
abstract: Lymphocyte migration into fresh and preserved peripheral nerve allografts was quantitated to assess the effect of cold preservation and freeze-thawing pretreatment on the local immunological response to nerve allografts. Out-bred ewes received multiple 1.5-cm subcutaneous heterotopic peroneal nerve autografts, fresh allografts, and pretreated allografts, implanted within the same recipient. Lymphocyte migration was studied at 7 days by injecting autologous 111indium-labeled lymphocytes intravenously. After 3 hr of recirculation, lymphocyte migration into graft tissue was quantitated by a gamma counter (epm/g, mean +/- SEM). Lymphocyte traffic into fresh nerve allografts (21,623 +/- 3783) increased an average 9.4-fold over the autograft value (2918 +/- 377, P < 0.04). Histologic studies illustrated a marked lymphocytic infiltrate of CD4+ and CD8+ cells and enhanced class I and II MHC expression in fresh allografts, but not in autografts. Short-term cold preservation, for 6 and 12 hr (5 degrees C), enhanced lymphocyte entry into pretreated allograft tissue. Conversely, cold preservation for longer periods (1 and 3 weeks) dramatically reduced lymphocyte migration to values below corresponding autograft levels (783 +/- 100 and 1,252 +/- 120, respectively, P < 0.01). A comparable reduction in lymphocyte migration into nerve allografts was observed after freeze-thawing pretreatment (P < 0.01). Cold preservation of donor allogeneic lymphocytes inhibited their capacity to induce intradermal host lymphocyte migration, implicating passenger lymphocytes as a potential cold-sensitive allogeneic component of the nerve allograft. Assessment of the local response to ovine peripheral nerve allografts, utilizing radiolabeled autologous lymphocytes, demonstrated that cold preservation and freeze-thawing pretreatment significantly reduced lymphocyte migration into nerve allografts. The mechanism(s) of reduced lymphocyte migration may involve inactivation or death of antigen-presenting cells, including passenger lymphocytes.
authors.affiliation: Department of Immunology, University of Toronto, Canada.
authors.forename: G M
authors.initials: GM
authors.lastname: Hare
authors.forename: P J
authors.initials: PJ
authors.lastname: Evans
authors.forename: S E
authors.initials: SE
authors.lastname: Mackinnon
authors.forename: Y
authors.initials: Y
authors.lastname: Nakao
authors.forename: R
authors.initials: R
authors.lastname: Midha
authors.forename: J A
authors.initials: JA
authors.lastname: Wade
authors.forename: D A
authors.initials: DA
authors.lastname: Hunter
authors.forename: J B
authors.initials: JB
authors.lastname: Hay
mesh_terms: D000818:Animals; D003080:Cold Temperature; D015925:Cryopreservation / Q000379:methods*; D005260:Female; D017710:Lymphocyte Transfusion; D008214:Lymphocytes / Q000502:physiology*; D009413:Nerve Fibers, Myelinated / Q000648:ultrastructure; D009926:Organ Preservation / Q000379:methods*; D010543:Peroneal Nerve / Q000502:physiology* / Q000637:transplantation*; D012756:Sheep; D013997:Time Factors; D014182:Transplantation, Autologous / Q000276:immunology; D014184:Transplantation, Homologous / Q000276:immunology; D014855:Wallerian Degeneration