Effects of anti-CD70 mAb on Theiler's murine encephalomyelitis virus-induced demyelinating disease

B cell depletion attenuates CD27 signaling of T helper cells in multiple sclerosis

Multiple sclerosis is a chronic inflammatory disease of the central nervous system. Whereas T cells are likely the main drivers of disease development, the striking efficacy of B cell-depleting therapies (BCDTs) underscore B cells' involvement in disease progression. How B cells contribute to multiple sclerosis (MS) pathogenesis-and consequently the precise mechanism of action of BCDTs-remains elusive. Here, we analyze the impact of BCDTs on the immune landscape in patients with MS using high-dimensional single-cell immunophenotyping. Algorithm-guided analysis reveals a decrease in circulating T follicular helper-like (Tfh-like) cells alongside increases in CD27 expression in memory T helper cells and Tfh-like cells. Elevated CD27 indicates disrupted CD27/CD70 signaling, as sustained CD27 activation in T cells leads to its cleavage. Immunohistological analysis shows CD70-expressing B cells at MS lesion sites. These results suggest that the efficacy of BCDTs may partly hinge upon the disruption of Th cell and B cell interactions.

Role of the Programmed Death-1 (PD-1) pathway in regulation of Theiler's murine encephalomyelitis virus-induced demyelinating disease

Programmed death-1 (PD-1) belongs to the CD28 family of co-stimulatory and co-inhibitory molecules and regulates adaptive immunity. This molecule induces the development of regulatory T cells, T cell tolerance, or apoptosis. We examined the role of PD-1 pathway in Theiler's murine encephalomyelitis virus (TMEV)-induced demyelinating disease (TMEV-IDD) mice. Up-regulation of PD-1 and PD-1 ligand-1 (PD-L1) mRNA expression in bone marrow-derived dendritic cells were induced by TMEV infection in vitro. Furthermore, PD-1 and PD-L1 mRNA expression was increased in the spinal cords of the TMEV-infected mice in vivo. Treatment with a blocking monoclonal antibody (mAb) against PD-1, especially during the effector phase, resulted in significant deterioration of the TMEV-IDD both clinically and histologically. Flow cytometric analysis revealed a dramatically increase of CD4(+) T cells producing Th1 cytokines such as IFN-γ and TNF-α in the spinal cord of anti-PD-1 mAb-treated mice. These results indicate that the PD-1 pathway plays a pivotal regulatory role in the development of TMEV-IDD.

Enhanced costimulation by CD70+ B cells aggravates experimental autoimmune encephalomyelitis in autoimmune mice

OBJECTIVE

Assess whether CD70+ B cells contribute to EAE.

MATERIALS AND METHODS

MOG-specific TCR transgenic mice (2D2) were crossed with mice with constitutive CD70 expression on B cells. The development of EAE and the phenotype of B-T lymphocytes were studied in 2D2xCD70 animals.

RESULTS

Spontaneous EAE developed in 20% of 2D2xCD70 and 3% of 2D2 mice. EAE was also more severe in 2D2xCD70 versus 2D2 animals upon MOG immunization. The susceptibility of 2D2xCD70 to EAE was associated with fewer FoxP3+ T cells.

CONCLUSIONS

Expression of CD70 by B cells aggravates EAE possibly by reducing the number of regulatory T cells.

TNF superfamily in inflammatory disease: translating basic insights

The tumor necrosis factor (TNF) and TNF receptor superfamilies (TNFSF and TNFRSF) consist of approximately 50 membrane and soluble proteins that can modulate cellular function. Most of these molecules are expressed by or can target cells of the immune system, and they have a wide range of actions including promoting cellular differentiation, survival, and production of inflammatory cytokines and chemokines. Emerging data show that TNFSF ligand-receptor signaling pathways are active in inflammatory and autoimmune disease. Furthermore, several genetic polymorphisms in TNFSF and TNFRSF associate with susceptibility to developing disease. Here, we examine recent data regarding the potential of these molecules as targets for therapy of autoimmune and inflammatory disease.

Autoimmune therapies targeting costimulation and emerging trends in multivalent therapeutics

Proteins participating in immunological signaling have emerged as important targets for controlling the immune response. A multitude of receptor-ligand pairs that regulate signaling pathways of the immune response have been identified. In the complex milieu of immune signaling, therapeutic agents targeting mediators of cellular signaling often either activate an inflammatory immune response or induce tolerance. This review is primarily focused on therapeutics that inhibit the inflammatory immune response by targeting membrane-bound proteins regulating costimulation or mediating immune-cell adhesion. Many of these signals participate in larger, organized structures such as the immunological synapse. Receptor clustering and arrangement into organized structures is also reviewed and emerging trends implicating a potential role for multivalent therapeutics is posited.