Corticosteroid treatment of experimental autoimmune encephalomyelitis in the Lewis rat results in loss of Vβ8.2+ and myelin basic protein-reactive cells from the spinal cord, with increased total T-cell apoptosis but reduced apoptosis of Vβ8.2+ cells

Abstract

We have studied the effects of corticosteroid treatment on the numbers of lymphocytes obtained from the spinal cords of Lewis rats with acute experimental autoimmune encephalomyelitis (EAE) induced by inoculation with myelin basic protein (MBP) and adjuvants. Flow cytometric studies showed that treatment with dexamethasone (4 mg/kg) 8-12 h prior to study on day 14 after inoculation resulted in a reduction in the numbers of CD5 + , TCR + and V 8.2 + cells in the spinal cord. Limiting dilution analysis indicated that dexamethasone treatment 12 h prior to study on day 12 after inoculation reduced the frequencies of MBP-reactive and interleukin-2-responsive lymphocytes in the spinal cord to low levels, but reduced the frequency of concanavalin-A-responsive lymphocytes to a lesser extent. Using propidium iodide staining of nuclear chromatin we also studied lymphocyte apoptosis. Greater numbers of apoptotic cells were found in the cells extracted from the spinal cords of rats, examined on day 14, that had been treated 1-12 h previously with dexamethasone, than in saline-treated controls. This increased level of apoptosis was observed in the CD5 + and TCR + cell populations. At 1-4 h after dexamethasone treatment there was a reduction in the selective apoptosis of V 8.2 + cells that normally occurs during spontaneous recovery from EAE. Therefore apoptosis of V 8.2 + cells cannot explain the reduction in the numbers of V 8.2 + cells and MBP-reactive cells in the CNS after dexamethasone treatment. By 8-12 h after dexamethasone treatment the selectivity of the apoptotic process was restored. These studies suggest that a reduction in the number of T-lymphocytes in the central nervous system contributes to the beneficial effects of corticosteroids in EAE.

Contrasting impact of corticosteroids on anti-PD-1 immunotherapy efficacy for tumor histologies located within or outside the central nervous system

“…51,52 Additionally, in studies of experimental autoimmune encephalomyelitis (EAE), a well-established rodent model of multiple sclerosis (MS), dexamethasone treatment induced apoptosis and inhibited the CNS migration of peripheral, bystander T cells with limited impact on CNS-resident, antigen-specific T cells. 35,53 Taken together, these data suggest there may be variability of corticosteroid’s influence on CNS-resident vs. peripheral T cells, and the current study’s findings demonstrate that anti-PD-1-mediated immune responses against intracranial tumors may potentially go undeterred in the setting of corticosteroids. Corticosteroid use did not correlate with the density of infiltrating T cells in a large cohort of patients with brain metastases.…”

Cytokine expression by inflammatory cells obtained from the spinal cords of Lewis rats with experimental autoimmune encephalomyelitis induced by inoculation with myelin basic protein and adjuvants

“…The cells were isolated from the spinal cords of anaesthetized rats perfused with ice-cold saline, as previously described (McCombe et al, 1996b). The spinal cord was removed by insufflation, weighed, and a single cell suspension in ice-cold RPMI 1640 containing 1% fetal calf serum (FCS) was prepared by passage through a 200 size mesh stainless steel sieve.…”

“…The cells were labelled for flow cytometric analysis using our previously described methods (McCombe et al, 1996b). Aliquots of 10 5 -10 6 cells were washed with a 1:1 solution of serum in phosphate-buffered saline (PBS) containing 1% fetal calf serum and 0.1% sodium azide, then incubated with primary antibodies in PBS/azide for 30 min at 4°C.…”

Corticosteroids for Multiple Sclerosis: I. Application for Treating Exacerbations

“…Limiting dilution analysis further revealed that the number of autoantigen-specific T cells was also decreased. 32 Notably, the numbers of apoptotic cells in the spinal cords of treated animals were increased compared with those observed in animals treated with saline. 32 This finding was consistent with the work of Pender et al, 33 who had previously demonstrated that cell apoptosis may be a major physiological mechanism of cell removal in acute EAE brain lesions.…”

“…The earliest evidence that CS may have beneficial effects in inflammatory CNS disorders was provided by Levine et al, 31 who demonstrated that therapeutic adrenalectomy enhanced the clinical signs of EAE. McCombe et al 32 showed that a single dose of dexamethasone (4 mg/kg) at disease onset resulted in a significant reduction in the numbers of T lymphocytes infiltrating into the spinal cord. Limiting dilution analysis further revealed that the number of autoantigen-specific T cells was also decreased.…”