ANALYSIS OF EPITOPE-SPECIFIC T CELLS IN SARS-CoV-2 INFECTION AND VACCINATION

Background: T cells play a critical role in the adaptive immune response to SARS-CoV-2 in both infection and vaccination. Identifying T cell epitopes and understanding how T cells recognize these epitopes can help inform future vaccine design and provide insight into T cell recognition of newly emerging variants. Here, we identified SARS-CoV-2 specific T cell epitopes, analyzed epitope-specific T cell repertoires, and characterized the potency and cross-reactivity of T cell clones across different common human coronaviruses (HCoVs). Method(s): SARS-CoV-2-specific T cell epitopes were determined by IFNgamma ELISpot using PBMC from convalescent individuals with mild/moderate disease (n=25 for Spike (S), Nucleocapsid (N) and Membrane (M)), and in vaccinated individuals (n=27 for S). Epitope-specific T cells were isolated based on activation markers following a 6-hour peptide stimulation, and scRNAseq was performed for TCR repertoire analysis. T cell lines were generated by expressing recombinant TCRs in Jurkat cells and activation was measured by CD69 upregulation. Result(s): We identified multiple immunodominant T cell epitopes across S, N and M proteins in convalescent individuals. In vaccinated individuals, we detected many of the same dominant S-specific epitopes at similar frequencies as compared to convalescent individuals. T cell responses to peptide S205 (amino acids 817-831) were observed in 56% and 59% of individuals following infection and vaccination, respectively, while 20% and 19% of individuals responded to S302 (a.a. 1205-1219) following infection and vaccination, respectively. For S205, a CD4+ T cell response, we confirmed 8 unique TCRs and determined the minimal epitope to be a 9mer (IEDLLFNKV). While TCR genes TRAV8-6*01 and TRBV30*01 were commonly utilized across the TCRs, we did identify TCRs with unique immunogenetic properties with different potencies of cross-reactivity to other HCoVs. For S302, a CD8+ T cell response, we identified two unique TCRs with different immunogenetic properties that recognized the same 9mer (YIKWPWYIW) and cross-reacted with different HCoV peptides (Figure 1). Conclusion(s): These data identify immunodominant T cell epitopes following SARS-CoV-2 infection and vaccination and provide a detailed analysis of epitope-specific TCR repertoires. The prospect of developing a vaccine that broadly protects against multiple human coronaviruses is bolstered by the identification of conserved immunodominant SARS-CoV-2 T cell epitopes that cross react with multiple other HCoVs.

Exploring the Existential Implications of COVID-19 in Health Communication

The coronavirus disease 2019 (COVID-19) pandemic provided an existential threat the world has rarely seen and forced Americans to make meaning in a world of uncertainty surrounding what most have taken for granted, being healthy. Reviewing data from several studies collected throughout the COVID-19 pandemic, this article uses COVID-19 as a case study to understand reasoning to follow (or not) the recommendations set forth by government agencies through understanding the effects of longitudinal death salience (i.e., long-term awareness of death). The Terror Management Health Model (TMHM) argues that death is a key component to the condition of human behavior to elongate life. If the TMHM is correct, then Americans should have widely followed government recommendations, but instead violence and a polarized America ensued. Implications for health communication and the TMHM are discussed, providing a path forward for health communication and existential psychology scholars. © 2023 SAGE Publications.

Tacrolimus Toxicity Due to Unrecognized Significance of Nirmatrelvir-Ritonavir Interaction in a Case Series of Solid Organ Transplant Recipients

Introduction: Nirmatrelvir-ritonovir (NIM-RTV) for COVID-19 increases tacrolimus (XR-Tac;IR-Tac) concentrations. Increased availability of NIM-RTV and ongoing COVID-19 infections, poses a significant risk to solid organ transplant (SOT) recipients. Case: Case 1 describes a 66-year-old (yo) male 1.5 years post-liver transplant on XR-Tac (goal 4-8 ng/mL). After 4 doses of NIM-RTV, XR-Tac was held and NIM-RTV continued. His tacrolimus level was 23.9 ng/mL and SCr 2.4 mg/dL (baseline 1.4 mg/dL) 3 days after holding XR-Tac. Case 2 was a 60 yo male 7 months post-lung transplant that received 2 doses of NIM-RTV + IR-Tac (goal 8-10 ng/mL). He experienced AKI (SCr 1.3 mg/dL, baseline 1.0 mg/dL) with a tacrolimus level >60 ng/mL. Tacrolimus and NIM-RTV were held and phenytoin initiated. The patient's SCr returned to baseline 5 days later. Case 3 includes a 53 yo male 2.5 years post-kidney transplant on XRTac (goal 4-6 ng/mL). Following 2 doses of NIM-RTV, he was hospitalized with a tacrolimus level >60 ng/mL, AKI (SCr 2.2 mg/dL, baseline 1.7 mg/dL) and nausea/vomiting. Both medications were held and phenytoin initiated. Tacrolimus and SCr returned to baseline 6 days later. Case 4 was a 75 yo female 19 years post-heart transplant on IRTac (goal 4-6 ng/mL). After 4 doses of NIM-RTV, she required hospital admission for AKI and vision changes. Tacrolimus level was >60 ng/mL. Phenytoin was started as IR-Tac and NIM-RTV were stopped. Tacrolimus, SCr, and vision returned to normal 4 days later. Discussion(s): Limited data and knowledge regarding severity of concomitant NIM-RTV/tacrolimus exists. Furthermore, there is no data describing the use of the CYP3A4 inducer phenytoin to reverse tacrolimus toxicity. Conclusion(s): Even after only a few doses of concomitant NIM-RTV and tacrolimus, there is a significant risk of tacrolimus toxicity. Phenytoin induction may serve to minimize the toxicities associated with supratherapeutic troughs above the upper limit of detection.

Systematic review of the impact of pre- and post-solid organ transplant chronic opioid use on recipient outcomes

Background: Chronic opioid use (COU) has been associated with negative outcomes in the general population but has not been systematically evaluated in solid organ transplant (SOT) recipients. This is a systematic review of the impact of pre- and post-transplant COU on recipient outcomes. Method(s): Electronic searches were performed in Medline, Embase, and Web of Science through date of inception to December 2021 for SOT and COU. A search alert was also conducted through Google Scholar. Literature was uploaded and managed through Covidence software. To reduce bias, title and s were independently screened and relevant articles underwent independent full text review. Conflicts at either stage were resolved by the senior author. Result(s): Literature search yielded 25,190 records and 8,258 were identified by Covidence as duplicate and removed. After title and screening of the remainder, 482 studies were read for eligibility, with 22 included in final assessment (kidney = 10;lung = 4;liver = 7;heart = 1). Ten studies (45.5%) were retrospective, 10 (45.5%) database analyses, and 2 (9.0%) were alternative methodology. Demographic differences and safety outcomes were the focus of most studies. Patient survival was assessed in 13 studies (59.1%). COU increased patient death in 9 (69.2%) of these studies with the remaining showing no impact on survival. Increased patient morality was noted in the following organ studies: heart = 1, kidney = 5, liver = 2, lung = 1. Depending on the allograft included in the study, COU had varying impacts on length of stay, hospital readmissions, and COU post-transplant. Discussion(s): The impact of COU on transplant outcomes is largely confined to retrospective and database analyses. With findings demonstrating a negative impact of COU on post-transplant survival, a more robust assessment of opioid minimization and sparing strategies on post-transplant outcomes is needed.

Impact of Nirmatrelvir-Ritonavir on Tacrolimus Concentrations

Purpose: Ritonavir (RTV), a component of the oral antiviral agent nirmatrelvir-RTV (Paxlovid) for COVID-19 infection, increases tacrolimus concentrations through strong competitive inhibition of gastrointestinal and hepatic CYP3A4 enzymes. The prescribing information for nirmatrelvir-RTV recommends against its use in combination with tacrolimus when close monitoring of serum concentrations is not feasible. Method(s): Herein we report a multicenter case series of 3 patients started on nirmatrelvir-RTV without the knowledge of the transplant team while taking concomitant tacrolimus. Result(s): Figure 1 outlines the time course and lab values for each patient. The first case is a 29 year old male 8 years post-kidney transplant, maintained on immediate release tacrolimus (IR-Tac) (goal 4-6 ng/mL), mycophenolate mofetil (MMF) 500 mg twice daily, and prednisone 5 mg daily. He took 5 doses of nirmatrelvir-RTV before discontinuing due to diarrhea. Six days after his first nirmatrelvir-RTV dose, his tacrolimus level was 95.5 ng/mL and serum creatinine (SCr) 2.8 mg/dL (baseline 2.2 mg/dL). Tacrolimus was discontinued, and 5 days later the level was 9.5 ng/mL. The second case is a 41 year old female 22 years post-kidney transplant, maintained on extended-release tacrolimus (XR-Tac;Envarsus) (goal 4-6 ng/mL) and prednisone 5 mg daily. She took 4 doses of nirmatrelvir-RTV before discontinuing due to diarrhea and headache, and continued her doses of XR-Tac throughout this time. Ten days after her first nirmatrelvir-RTV dose, her tacrolimus level was 4.4 ng/mL and SCr 2.6 mg/dL (baseline 2.0 mg/dL). The third case is a 66 year old male 1.5 years post-liver transplant, maintained on XR-Tac (goal 4-8 ng/mL) and MMF 500 mg twice daily. He took 4 doses of nirmatrelvir-RTV and then XR-Tac was held while completing nirmatrelvir-RTV therapy. Five days after his first nirmatrelvir- RTV dose and 3 days after his XR-Tac was held, his tacrolimus level was 23.9 ng/ mL and SCr 2.4 mg/dL (baseline 1.4 mg/dL). Conclusion(s): In this case series of 3 patients who took nirmatrelvir-RTV while on tacrolimus, duration of nirmatrelvir-RTV and time course of tacrolimus adjustment were variable, and all patients had a rise in SCr from baseline. Given the extreme elevation of tacrolimus concentrations in the patient taking IR-Tac, further study is needed to systematically characterize the variability of this drug interaction between tacrolimus formulations.

TCR SEQUENCING of EPITOPE-SPECIFIC T CELLS from SARS-CoV-2 CONVALESCENT INDIVIDUALS

Background: T cells have been shown to play a role in the immune response to SARS-CoV-2. Identification of T cell epitopes and a better understanding of the T cell repertoire will provide important insights into how T cells impact antiviral immunity. Here, we identified T cell epitopes within the Spike (S), Nucleocapsid (N) and Membrane (M) proteins from SARS-CoV-2 convalescent individuals and performed TCR sequencing on epitope-specific T cells. Methods: Epitope mapping was performed by IFNγ ELISpot on PBMC from SARS-CoV-2 convalescent patients with mild/moderate disease (n = 19 for S;n=15 for N and M), and minimum epitopes were determined using truncated peptides and ICS. TCR sequence analysis was performed on a subset of individuals (n=9 donors;2-3 epitopes/donor), with longitudinal samples for 7 donors (2-3 time points/donor;33 to 236 days post-symptom onset). T cells were stimulated with individual peptides for 6 hours and sorted based on the expression of activation markers (CD4+: CD69, CD40L;CD8+: CD69, CD107a, surface TNF). scRNAseq was performed on sorted cells for TCR repertoire and transcriptome analysis. Results: We identified several peptides recognized by multiple individuals, including S42 (amino acids 165-179;7/19 donors), S302 (a.a. 1205-1219;6/19 donors), N27 (a.a. 106-120;6/14 donors) and M45 (a.a. 177-191;10/14 donors). S42 elicited both CD4+ (n=5) and CD8+ (n=1) T cell responses, with one individual having both a CD4+ and CD8+ response. The minimum epitope for S42 was determined to be a 9mer (FEYVSQPFL) for both CD4+ and CD8+ cells. TCR sequencing of S42-specific T cells identified a dominant gene pairing for TCRα across multiple donors (TRAV35;TRAJ42) and for both CD4+ and CD8+ T cells (Figure 1). In general, epitope-specific CD4+ responses (S42, M45) were more clonally diverse than CD8+ responses (S42, S302, N27). For both CD4+ and CD8+ T cells, conserved TCR gene usage and gene pairings could be identified within multiple donors responding to the same epitope. Conclusion: These data suggest that in SARS-CoV-2 convalescent people, epitope-specific CD4+ and CD8+ T cells can differ in their clonal diversity and that related TCRs can be identified across multiple donors. S42-specific T cell studies are ongoing to determine their transcriptional profile and pMHC presentation. Ongoing longitudinal analysis will provide a better understanding of different epitope-specific TCR repertoires and T cell transcriptional profiles, and how they evolve after infection.

Real-world Evaluation of SARS-CoV-2 Monoclonal Antibodies in Solid Organ Transplant Recipients

Background. Patients with COVID-19 infection at highest risk for poor outcomes include immunocompromised patients, such as solid organ transplant (SOT) recipients. Monoclonal antibody (mAb) infusions were developed to promote passive immunity. Analysis of the first 200 patients who received SARS-CoV-2 mAb at our hospital showed a 27 % absolute reduction in hospitalization and emergency department (ED) visits. Understanding the role of SARS-CoV-2 mAb therapy in management of the SOT population is likely to inform decision making for these patients. Methods. We conducted a retrospective chart review of SOT patients diagnosed with COVID-19 who received mAb therapy between 11/18/20 and 04/26/21. Patients were excluded if they were < 18 years of age or if they weighed < 40 kg. We compared those patients who were hospitalized or visited the ED within 29 days of mAb therapy to those who recovered without further visits to our hospital. Results. A total of 50 SOT patients receiving mAb therapy were included in this analysis. Bamlanivimab was given to 33 patients, while 9 patients received bamlanivimab/ etesevimab and 8 patients received casirivimab/imdevimab. Twelve (24 %) patients were hospitalized or visited the ED within 29 days of mAb therapy;38 patients did not. These 2 groups did not significantly differ by age, gender, body mass index, time from SOT, or other risk factors for severe COVID-19 illness per FDA Emergency Use Authorization guidance. Both groups were primarily made up of kidney transplant recipients (66.7 % and 68.4 %, respectively). Significantly more patients in the hospitalization/ ED group were receiving antimetabolites as part of their immunosuppression (IS) regimen prior to COVID-19 diagnosis (100 % vs 68.4 %, p = 0.047). Patients in the hospitalization/ED group received mAbs within a median of 6 days (IQR 3.8) of symptom onset compared to 4 days (IQR 4) (p = 0.006). Conclusion. SOT recipients were more likely to be hospitalized or visit the ED due to COVID-19 after mAb if they were receiving antimetabolite IS or received mAb later after symptom onset. These data stress the importance of early mAb administration in all SOT patients, particularly in those on antimetabolite therapy.

Equity in designing a summer international research experience: Recruitment and partnerships for a graduate field school in El Salvador

An inclusive international research experience for graduate students is being developed based on equitable, interdisciplinary opportunities in field research and training and proactive efforts in recruiting a diverse cohort. Michigan Technological University, the Consortium of Universities for the Advancement of Hydrologic Science, Inc., and Lutheran World Relief are collaborating to support local development interventions for agricultural and water-access challenges in the "Dry Corridor" of El Salvador. The three-year effort is supported by the National Science Foundation International Research Experiences for Students program. This project, titled "Agricultural Community Adaptations to Extreme Hydrometeorological Events," recruited students for the summer 2020 experience before the COVID-19 interruption. Lessons from this past year pertaining to student recruitment, application selection, and preparatory training will enhance the processes for the coming year. Students were recruited through professional meetings, listservs, social media, and professional contacts. Proactive efforts were implemented to broaden student diversity. The selection process was systematically structured to evaluate applicant experience abroad, language abilities, and academic program relevance to the project goals. Pre-departure training content was developed to provide students with relevant tools and background for the travel, living, and research methods training in El Salvador. The project teams work with universities and governmental agencies in El Salvador. Agronomists, hydrologists, geologists, social scientists, and engineers are collaborating to explore new ways to couple participatory and hydrological research for informing adaptive strategies to water scarcity in agricultural communities. A planning visit in 2019 sought input from local farmers, representatives from governmental and non-governmental institutions, and project partners to help prioritize project research plans. This pre-planning approach fostered greater integration of the interdisciplinary project activities;planning to enhance local engagement in field work and continuous data collection;and development of insightful recruitment and promotional materials. © ASCE.