Serum Soluble CD48 Levels as a Prognostic Marker in Mycosis Fungoides and Sézary Syndrome

Oka, Tomonori; Miyagaki, Tomomitsu; Takahashi, Naomi; Nakajima, Rina; Kamijo, Hiroaki; Suga, Hiraku; Asano, Yoshihide; Sugaya, Makoto; Sato, Shinichi

doi:10.1016/j.jid.2018.03.1519

Cited by 3 publications

(1 citation statement)

References 11 publications

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“…Interestingly, CD48 has also been identified as a soluble form in human serum, and shown to be at increased levels in patients with arthritis, mild asthma, and advanced lymphoid malignancies, potentially acting as an antagonist or decoy receptor capable of blocking CD48:2B4 binding [44–46]. Thus, considering the exceptional binding kinetic features of A43 compared to human CD48, one key aspect derived from this work is the potential of using A43 to develop novel therapeutic tools to manipulate aberrant immune responses, such as autoimmune diseases.…”

Section: Discussionmentioning

confidence: 99%

Subversion of natural killer cell responses by a cytomegalovirus-encoded soluble CD48 decoy receptor

et al. 2019

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Throughout evolution, cytomegaloviruses (CMVs) have been capturing genes from their hosts, employing the derived proteins to evade host immune defenses. We have recently reported the presence of a number of CD48 homologs (vCD48s) encoded by different pathogenic viruses, including several CMVs. However, their properties and biological relevance remain as yet unexplored. CD48, a cosignaling molecule expressed on the surface of most hematopoietic cells, modulates the function of natural killer (NK) and other cytotoxic cells by binding to its natural ligand 2B4 (CD244). Here, we have characterized A43, the vCD48 exhibiting the highest amino acid sequence identity with host CD48. A43, which is encoded by owl monkey CMV, is a soluble molecule released from the cell after being proteolytically processed through its membrane proximal region. A43 is expressed with immediate-early kinetics, yielding a protein that is rapidly detected in the supernatant of infected cells. Remarkably, surface plasmon resonance assays revealed that this viral protein binds to host 2B4 with high affinity and slow dissociation rates. We demonstrate that soluble A43 is capable to abrogate host CD48:2B4 interactions. Moreover, A43 strongly binds to human 2B4 and prevents 2B4-mediated NK-cell adhesion to target cells, therefore reducing the formation of conjugates and the establishment of immunological synapses between human NK cells and CD48-expressing target cells. Furthermore, in the presence of this viral protein, 2B4-mediated cytotoxicity and IFN-γ production by NK cells are severely impaired. In summary, we propose that A43 may serve as a functional soluble CD48 decoy receptor by binding and masking 2B4, thereby impeding effective NK cell immune control during viral infections. Thus, our findings provide a novel example of the immune evasion strategies developed by viruses.

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Section: Discussionmentioning

confidence: 99%