A critical epitope in CD147 facilitates memory CD4^(+) T-cell hyper-activation in rheumatoid arthritis

The abnormal activation of CD4^(+)CD45RO+memory T(Tm)cells plays an important role in the pathogenesis of rheumatoid arthritis(RA).Previous studies have shown that CD147 participates in T-cell activation.However,it remains unclear whether CD147 is involved in abnormal Tm-cell activation in RA patients.In this study,we demonstrated that CD147 was predominantly upregulated in Tm cells derived from RA patients.The anti-CD147 mAb 5A12 specifically inhibited Tm-cell activation and proliferation and further restrained osteoclastogenesis.Using a structural–functional approach,we depicted the interface between 5A12 and CD147.This allowed us to identify two critical residues,Lys63 and Asp65,as potential targets for RA treatment,as the double mutation K63A/D65A inhibited Tm-cell activation,mimicking the neutralization by 5A12.This study provides not only a theoretical basis for a“CD147-Tm/Osteoclast-RA chain”for the potential prevention and treatment of RA or other T-cell-mediated autoimmune diseases but also a new target for related drug design and development.

CD147 antibody specifically and effectively inhibits infection and cytokine storm of SARS-CoV-2 and its variants delta,alpha,beta,and gamma

SARS-CoV-2 mutations contribute to increased viral transmissibility and immune escape,compromising the effectiveness of existing vaccines and neutralizing antibodies.An in-depth investigation on COVID-19 pathogenesis is urgently needed to develop a strategy against SARS-CoV-2 variants.Here,we identified CD147 as a universal receptor for SARS-CoV-2 and its variants.Meanwhile,Meplazeumab,a humanized anti-CD147 antibody,could block cellular entry of SARS-CoV-2 and its variants-alpha,beta,gamma,and delta,with inhibition rates of 68.7,75.7,52.1,52.1,and 62.3%at 60μg/ml,respectively.Furthermore,humanized CD147 transgenic mice were susceptible to SARS-CoV-2 and its two variants,alpha and beta.When infected,these mice developed exudative alveolar pneumonia,featured by immune responses involving alveoli-infiltrated macrophages,neutrophils,and lymphocytes and activation of IL-17 signaling pathway.Mechanistically,we proposed that severe COVID-19-related cytokine storm is induced by a"spike protein-CD147-CyPA signaling axis":Infection of SARS-CoV-2 through CD147 initiated the JAK-STAT pathway,which further induced expression of cyclophilin A(CyPA);CyPA reciprocally bound to CD147 and triggered MAPK pathway.Consequently,the MAPK pathway regulated the expression of cytokines and chemokines,which promoted the development of cytokine storm.Importantly,Meplazumab could effectively inhibit viral entry and inflammation caused by SARS-CoV-2 and its variants.Therefore,our findings provided a new perspective for severe COVID-19-related pathogenesis.Furthermore,the validated universal receptor for SARS-CoV-2 and its variants can be targeted for COVID-19 treatment.