T-cell co-stimulation by CD28-CD80/86 and its negative regulator CTLA-4 strongly influence accelerated atherosclerosis development.

ABSTRACT

OBJECTIVE: T-cells are central to the immune response responsible for native atherosclerosis. The objective of this study is to investigate T-cell contribution to post-interventional accelerated atherosclerosis development, as well as the role of the CD28-CD80/86 co-stimulatory and Cytotoxic T-Lymphocyte Antigen (CTLA)-4 co-inhibitory pathways controlling T-cell activation status in this process. METHODS AND RESULTS: The role of T-cells and the CD28-CD80/86 co-stimulatory and CTLA-4 co-inhibitory pathways were investigated in a femoral artery cuff mouse model for post-interventional remodeling, with notable intravascular CTLA-4+ T-cell infiltration. Reduced intimal lesions developed in CD4(-/-) and CD80(-/-)CD86(-/-) mice compared to normal C57Bl/6J controls. Systemic abatacept-treatment, a soluble CTLA-4Ig fusion protein that prevents CD28-CD80/86 co-stimulatory T-cell activation, prevented intimal thickening by 58.5% (p=0.029). Next, hypercholesterolemic ApoE3*Leiden mice received abatacept-treatment which reduced accelerated atherosclerosis development by 78.1% (p=0.040) and prevented CD4 T-cell activation, indicated by reduced splenic fractions of activated KLRG1+, PD1+, CD69+ and CTLA-4+ T-cells. This correlated with reduced plasma interferon-γ and elevated interleukin-10 levels. The role of CTLA-4 was confirmed using CTLA-4 blocking antibodies, which strongly increased vascular lesion size by 66.7% (p=0.008), compared to isotype-treated controls. CONCLUSIONS: T-cell CD28-CD80/86 co-stimulation is vital for post-interventional accelerated atherosclerosis development and is regulated by CTLA-4 co-inhibition, indicating promising clinical potential for prevention of post-interventional remodeling by abatacept.