Translation suppression underlies the restrained COVID-19 mRNA vaccine response in the high-risk immunocompromised group.

Background: Immunocompromised (IC) patients show diminished immune response to COVID-19 mRNA vaccines (Co-mV). To date, there is no 'empirical' evidence to link the perturbation of translation, a rate-limiting step for mRNA vaccine efficiency (VE), to the dampened response of Co-mV. Materials and methods: Impact of immunosuppressants (ISs), tacrolimus (T), mycophenolate (M), rapamycin/sirolimus (S), and their combinations on Pfizer Co-mV translation were determined by the Spike (Sp) protein expression following Co-mV transfection in HEK293 cells. In vivo impact of ISs on SARS-CoV-2 spike specific antigen (SpAg) and associated antibody levels (IgGSp) in serum were assessed in Balb/c mice after two doses (2D) of the Pfizer vaccine. Spike Ag and IgGSp levels were assessed in 259 IC patients and 50 healthy controls (HC) who received 2D of Pfizer or Moderna Co-mV as well as in 67 immunosuppressed solid organ transplant (SOT) patients and 843 non-transplanted (NT) subjects following three doses (3D) of Co-mV. Higher Co-mV concentrations and transient drug holidays were evaluated. Results: We observed significantly lower IgGSP response in IC patients (p<0.0001) compared to their matched controls in 2D and 3D Co-mV groups. IC patients on M or S showed a profound dampening of IgGSP response relative to those that were not on these drugs. M and S, when used individually or in combination, significantly attenuated the Co-mV-induced Sp expression, whereas T did not exert significant influence. Sirolimus combo pretreatment in vivo significantly attenuated the Co-mV induced IgMSp and IgGSp production, which correlated with a decreasing trend in the early levels (after day 1) of Co-mV induced Sp immunogen levels. Neither higher Co-mV concentrations (6µg) nor withholding S for 1-day could overcome the inhibition of Sp protein levels. Interestingly, 3-days S holiday or using T alone rescued Sp levels in vitro. Conclusions: This is the first study to demonstrate that ISs, sirolimus and mycophenolate inhibited Co-mV-induced Sp protein synthesis via translation repression. Selective use of tacrolimus or drug holiday of sirolimus can be a potential means to rescue translation-dependent Sp protein production. These findings lay a strong foundation for guiding future studies aimed at improving Co-mV responses in high-risk IC patients.

Effects of immunophilin inhibitors and non-immunosuppressive analogs on coronavirus replication in human infection models.

Rationale: Human coronaviruses (HCoVs) seriously affect human health by causing respiratory diseases ranging from common colds to severe acute respiratory diseases. Immunophilins, including peptidyl-prolyl isomerases of the FK506-binding protein (FKBP) and the cyclophilin family, are promising targets for pharmaceutical inhibition of coronavirus replication, but cell-type specific effects have not been elucidated. FKBPs and cyclophilins bind the immunosuppressive drugs FK506 and cyclosporine A (CsA), respectively. Methods: Primary human bronchial epithelial cells (phBECs) were treated with CsA, Alisporivir (ALV), FK506, and FK506-derived non-immunosuppressive analogs and infected with HCoV-229E. RNA and protein were assessed by RT-qPCR and immunoblot analysis. Treatment with the same compounds was performed in hepatoma cells (Huh-7.5) infected with HCoV-229E expressing Renilla luciferase (HCoV-229E-RLuc) and the kidney cell line HEK293 transfected with a SARS-CoV-1 replicon expressing Renilla luciferase (SARS-CoV-1-RLuc), followed by quantification of luminescence as a measure of viral replication. Results: Both CsA and ALV robustly inhibited viral replication in all models; both compounds decreased HCoV-229E RNA in phBECs and reduced luminescence in HCoV-229E-RLuc-infected Huh7.5 and SARS-CoV-1-RLuc replicon-transfected HEK293. In contrast, FK506 showed inconsistent and less pronounced effects in phBECs while strongly affecting coronavirus replication in Huh-7.5 and HEK293. Two non-immunosuppressive FK506 analogs had no antiviral effect in any infection model. Conclusion: The immunophilin inhibitors CsA and ALV display robust anti-coronaviral properties in multiple infection models, including phBECs, reflecting a primary site of HCoV infection. In contrast, FK506 displayed cell-type specific effects, strongly affecting CoV replication in Huh7.5 and HEK293, but inconsistently and less pronounced in phBECs.

The Cyclophilin-Dependent Calcineurin Inhibitor Voclosporin Inhibits SARS-CoV-2 Replication in Cell Culture.

Kidney transplant recipients (KTRs) are at increased risk for a more severe course of COVID-19, due to their pre-existing comorbidity and immunosuppression. Consensus protocols recommend lowering immunosuppression in KTRs with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, but the optimal combination remains unclear. Calcineurin inhibitors (CNIs) are cornerstone immunosuppressants used in KTRs and some have been reported to possess antiviral activity against RNA viruses, including coronaviruses. Here, we evaluated the effect of the CNIs tacrolimus, cyclosporin A, and voclosporin (VCS), as well as other immunosuppressants, on SARS-CoV-2 replication in cell-based assays. Unexpected, loss of compound due to plastic binding and interference of excipients in pharmaceutical formulations (false-positive results) complicated the determination of EC50 values of cyclophilin-dependent CNI's in our antiviral assays. Some issues could be circumvented by using exclusively glass lab ware with pure compounds. In these experiments, VCS reduced viral progeny yields in human Calu-3 cells at low micromolar concentrations and did so more effectively than cyclosporin A, tacrolimus or other immunosuppressants. Although, we cannot recommend a particular immunosuppressive regimen in KTRs with COVID-19, our data suggest a potential benefit of cyclophilin-dependent CNIs, in particular VCS in reducing viral progeny, which warrants further clinical evaluation in SARS-CoV-2-infected KTRs.

SARS-CoV2 and immunosuppression: A double-edged sword.

Severe acute respiratory syndrome Coronavirus 2 (SARS-Cov2) outbreak has caused a pandemic rapidly impacting on the way of life of the entire world. This impact in the specific setting of transplantation and immunosuppression has been poorly explored to date. Discordant data exist on the impact of previous coronavirus outbreaks on immunosuppressed patients. Overall, only a very limited number of cases have been reported in literature, suggesting that transplanted patients not necessarily present an increased risk of severe SARS-Cov2-related disease compared to the general population. We conducted a literature review related to the impact of immunosuppression on coronavirus infections including case reports and series describing immunosuppression management in transplant recipients. The role of steroids, calcineurin inhibitors, and mycophenolic acid has been explored more in detail. A point-in-time snapshot of the yet released literature and some considerations in relation to the use of immunosuppression in SARS-Cov2 infected transplant recipients are provided here for the physicians dealing with immunocompromised patients.