Pretreatment with portal venous ultraviolet B-irradiated donor alloantigen promotes donor-specific tolerance to rat nerve allografts.
OBJECTIVE
To determine if a single intraportal inoculation of ultraviolet B-irradiated (UVB) donor splenocytes can prevent nerve allograft rejection and confer donor-specific immunotolerance to rat nerve allograft segments.


METHODS
Age-matched, class I and class II major histocompatibility complex (MHC) mismatched Buffalo (RT1b) rats were transplanted with a syngeneic nerve isograft, a Lewis (RT1l) nerve allograft, or a Brown-Norway (RT1n) rat nerve allograft segment. Control Buffalo rats in group I received a 3.0-cm Lewis (RT11) sciatic-posterior tibial interposition nerve allograft without pretreatment; group II Buffalo rats received a syngeneic Buffalo nerve isograft without pretreatment. Group III Buffalo recipients were inoculated with 2.5 x 107 UVB-irradiated Lewis donor splenocyte cells by portal venous administration 7 days before transplantation with a 3.0-cm sciatic-posterior tibial nerve allograft from a Lewis (RT11) or a third party Brown-Norway rat (RT1n) donor (group IV). Nerve graft regeneration was assessed with walking track analysis, nerve conduction studies, retrograde neural tracing, nerve graft histology, and morphometry. Recipient immune tolerance was assessed through in vitro immunological assessment.


RESULTS
Pretreatment with UVB-irradiated donor splenocytes 7 days before transplantation prevented nerve allograft rejection. Pretreated animals receiving a nerve allograft recovered limb function, and demonstrated morphological, histological, and electrophysiologic parameters of nerve regeneration similar to that measured in rats receiving a nerve isograft. In vitro immunological assessment by mixed lymphocyte culture (MLC), cytotoxic T lymphocyte (CTL) assay, limiting dilution analysis (LDA) of helper (pTH) and cytotoxic (pCTL) precursor frequencies, and IL-2 production demonstrated a marked donor-specific suppression in allografted animals pretreated with intraportal UVB-irradiated donor splenocytes. These assessments correlated with indefinite acceptance of donor nerve allografts.


CONCLUSIONS
A single pretreatment with a single intraportal dose of UVB-modified donor antigen specifically induces tolerance to peripheral nerve allografts in rats.
Department of Otolaryngology-Head and Neck Surgery, The Mount Sinai School of Medicine, St. Louis, Missouri, USA. eric.genden@mssm.edu
E M
EM
Genden
S E
SE
Mackinnon
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S
Yu
D A
DA
Hunter
M W
MW
Flye
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology / Q000528:radiation effects; D003601:Cytotoxicity Tests, Immunologic; D006084:Graft Rejection / Q000276:immunology* / Q000473:pathology; D007519:Isoantigens / Q000276:immunology / Q000528:radiation effects*; D009416:Nerve Regeneration / Q000276:immunology; D010525:Peripheral Nerves / Q000276:immunology / Q000473:pathology / Q000637:transplantation*; D051381:Rats; D011919:Rats, Inbred Strains; D012584:Sciatic Nerve / Q000276:immunology / Q000473:pathology / Q000637:transplantation; D013979:Tibial Nerve / Q000276:immunology / Q000473:pathology; D023001:Transplantation Tolerance / Q000528:radiation effects*; D014184:Transplantation, Homologous; D014466:Ultraviolet Rays
D007519:Isoantigens