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Exp Biol Med (Maywood). 2016 Jan;241(1):71-8. doi: 10.1177/1535370215596384. Epub 2015 Jul 22.

Opioid growth factor and low-dose naltrexone impair central nervous system infiltration by CD4 + T lymphocytes in established experimental autoimmune encephalomyelitis, a model of multiple sclerosis.

Author information

1
Department of Neural & Behavioral Science, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA.
2
Department of Microbiology & Immunology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA.
3
Department of Neural & Behavioral Science, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA pxm9@psu.edu.

Abstract

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS), characterized by infiltrating myelin-reactive T lymphocytes and demyelinating lesions. Experimental autoimmune encephalomyelitis (EAE) is the animal model widely utilized to study MS. EAE is mediated by CD4(+) T cells and can be induced in EAE-susceptible mice through immunization with a myelin antigen, such as proteolipid protein 139-151 (PLP139-151) in SJL mice. In this PLP-induced EAE model, autoreactive CD4(+) T cells migrate from peripheral tissues into the CNS where they are reactivated resulting in CNS damage. Th1 and Th17 cells produce the pro-inflammatory cytokines IFNγ and IL-17, respectively, that have been shown to have pathogenic roles in EAE and MS. Anti-inflammatory Th2, IL-4 secreting cells, have been indicated to inhibit EAE exacerbation. However, given the inflammatory environment of EAE, Th2 effector cells are outnumbered by Th1/Th17 cells. Regulatory CD4(+) T cells suppress immune reactions and have been demonstrated to be dysfunctional in MS patients. Opioid growth factor (OGF), chemically termed [Met(5)]-enkephalin, is a negative growth factor that interacts with the OGF receptor. The OGF-OGFr axis can be activated through exogenous administration of OGF or a low dosage of naltrexone (LDN), an opioid antagonist. We have previously demonstrated that modulation of the OGF-OGFr axis results in alleviation from relapse-remitting EAE, and that CNS-infiltrating CD3(+) T cells are diminished with exogenous OGF or intermittent blockade with LDN administration. In this paper, we aimed to determine whether OGF or LDN alter the Th effector responses of CD4(+) T lymphocytes within the CNS in established EAE. We report in these studies that the numbers of CD4(+) T lymphocytes in the CNS of EAE mice are decreased following treatment with OGF for five days but not LDN. However, modulation of the OGF-OGFr axis did not result in changes to CD4(+) Th effector cell responses in the CNS of EAE mice.

KEYWORDS:

IL-17; IL-2; IL-4; OGF; cytokines; flow cytometry; low-dose naltrexone; multiple sclerosis; spinal cord

PMID:
26202376
PMCID:
PMC4935426
DOI:
10.1177/1535370215596384
[Indexed for MEDLINE]
Free PMC Article

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