Abstract Details

Title Evaluating the Effect of Cladribine on Marmoset B- and T-Cell Proliferation and Survival

Topic Multiple Sclerosis

Presentation(s) P2 - Poster Session 2 (5:30 PM-6:30 PM)

Poster/Presentation
Number 15-056

Objective To assess cladribine’s effect on marmoset lymphocyte survival and proliferation in vitro and deoxycytidine (dCTP) levels in marmoset blood.

Background Translational experimental autoimmune encephalomyelitis (EAE) marmoset models have been used to assess peripheral and central activities of B-/T-cell-targeting multiple sclerosis drugs, without rodent species cross-reactivity. Here we present the feasibility of using an EAE marmoset model to assess selective depletion of lymphocyte subsets in blood, lymphoid organs and central nervous system following cladribine exposure.

Design/Methods Following exposure to cladribine (1nM-100mM), in vitro proliferation and survival of naïve and activated (concanavalin A [ConA], phytohemagglutinin, MOG34-56, recombinant hMOG) peripheral blood mononuclear cells (PBMC), spleen/lymph nodes mononuclear cells and Epstein-Barr virus (EBV)-infected B-cells were assessed. Cells were cultured for 24, 48 or 72 hours before lymphocyte proliferation and survival analysis. Marmoset dCTP levels were measured by reverse-phase chromatography.

Results Naïve and mitogen-stimulated (phytohemagglutinin/ConA) PBMC demonstrated dose-dependent declines in proliferation (~40% for cladribine 1mM/72h; 100% for 10mM/72h). No difference in efficacy was seen between naïve versus stimulated cells. CD20⁺ B-cells were more sensitive to cladribine than CD3⁺ T-cells in the survival assay. Analysis of MOG34-56 and MOG protein re-stimulated spleen/lymph node mononuclear cells from EAE marmosets confirmed a dose-dependent effect of cladribine after antigen stimulation (100nM-500nM). EBV-infected B-cells demonstrated reductions in proliferation with cladribine (~60-100% inhibition at 1-5mM/72h). EBV-infected B-cell survival was unaffected by cladribine. Low dCTP concentrations were detectable in marmoset blood.

Conclusions Cladribine concentrations as low as 1µM can inhibit proliferation of naïve or activated PBMC. B-cells were more sensitive than T-cells to cladribine-induced cell death. Cladribine inhibited proliferation and survival of marmoset EAE spleen/lymph node mononuclear cells after antigen re-stimulation and inhibited proliferation, but not survival, of EBV-infected marmoset B-cells.

Authors/Disclosures
PRESENTER	No disclosure on file
Ursula Boschert Shafaatian (C/o Serono)	Ursula Boschert has nothing to disclose.
Bert A. Hart, PhD (Biomedical Primate Research Centre)	No disclosure on file

��ɫ��

��ɫ��