Biology subjects

Zayou, L.

Publications and source records attributed to Zayou, L..

9 recordsLinked to original sources

bioRxiv2024

A Broad-Spectrum Multi-Antigen mRNA/LNP-Based Pan-Coronavirus Vaccine Induced Potent Cross-Protective Immunity Against Infection and Disease Caused by Highly Pathogenic and Heavily Spike-Mutated SARS-CoV-2 Variants of Concern in the Syrian Hamster Model

The first-generation Spike-alone-based COVID-19 vaccines have successfully contributed to reducing the risk of hospitalization, serious illness, and death caused by SARS-CoV-2 infections. However, waning immunity induced by these vaccines failed to prevent immune escape by many variants of concern (VOCs) that emerged from 2020 to 2024, resulting in a prolonged COVID-19 pandemic. We hypothesize that a next-generation Coronavirus (CoV) vaccine incorporating highly conserved non-Spike SARS-CoV-2 antigens would confer stronger and broader cross-protective immunity against multiple VOCs. In the present study, we identified ten non-Spike antigens that are highly conserved in 8.7 million SARS-CoV-2 strains, twenty-one VOCs, SARS-CoV, MERS-CoV, Common Cold CoVs, and animal CoVs. Seven of the 10 antigens were preferentially recognized by CD8+ and CD4+ T-cells from unvaccinated asymptomatic COVID-19 patients, irrespective of VOC infection. Three out of the seven conserved non-Spike T cell antigens belong to the early expressed Replication and Transcription Complex (RTC) region, when administered to the golden Syrian hamsters, in combination with Spike, as nucleoside-modified mRNA encapsulated in lipid nanoparticles (LNP) (i.e., combined mRNA/LNP-based pan-CoV vaccine): (i) Induced high frequencies of lung-resident antigen-specific CXCR5+CD4+ T follicular helper (TFH) cells, GzmB+CD4+ and GzmB+CD8+ cytotoxic T cells (TCYT), and CD69+IFN-{gamma}+TNF+CD4+ and CD69+IFN-{gamma}+TNF+CD8+ effector T cells (TEFF); and (ii) Reduced viral load and COVID-19-like symptoms caused by various VOCs, including the highly pathogenic B.1.617.2 Delta variant and the highly transmittable heavily Spike-mutated XBB1.5 Omicron sub-variant. The combined mRNA/LNP-based pan-CoV vaccine could be rapidly adapted for clinical use to confer broader cross-protective immunity against emerging highly mutated and pathogenic VOCs. IMPORTANCEAs of January 2024, over 1500 individuals in the United States alone are still dying from COVID-19 each week despite the implementation of first-generation Spike-alone-based COVID-19 vaccines. The emergence of highly transmissible SARS-CoV-2 variants of concern (VOCs), such as the currently circulating highly mutated BA.2.86 and JN.1 Omicron sub-variants, constantly overrode immunity induced by the first-generation Spike-alone-based COVID-19 vaccines. Here we report a next generation broad spectrum combined multi-antigen mRNA/LNP-based pan-CoV vaccine that consists of nucleoside-modified mRNA encapsulated in lipid nanoparticles (LNP) that delivers three highly conserved non-Spike viral T cell protein antigens together with the Spike protein B-cell antigen. Compared side-by-side to the clinically proven first-generation Spike-alone mRNA/LNP-based vaccine, the combined multi-antigen mRNA/LNP-based pan-CoV vaccine-induced higher frequencies of lung-resident non-Spike antigen-specific T follicular helper (TFH) cells, cytotoxic T cells (TCYT), effector T cells (TEFF) and Spike specific-neutralizing antibodies. This was associated to a potent cross-reactive protection against various VOCs, including the highly pathogenic Delta variant and the highly transmittable heavily Spike-mutated Omicron sub-variants. Our findings suggest an alternative broad-spectrum pan-Coronavirus vaccine capable of (i) disrupting the current COVID-19 booster paradigm; (ii) outpacing the bivalent variant-adapted COVID-19 vaccines; and (iii) ending an apparent prolonged COVID-19 pandemic.

immunology↗

bioRxiv2023

Therapeutic Prime/Pull Vaccination of HSV-2 Infected Guinea Pigs with the Ribonucleotide Reductase 2 (RR2) Protein and CXCL11 Chemokine Boosts Antiviral Local Tissue-Resident and Effector Memory CD4+ and CD8+ T Cells and Protects Against Recurrent Genital Herpes

Following acute herpes simplex virus type 2 (HSV-2) infection, the virus undergoes latency in sensory neurons of the dorsal root ganglia (DRG). Intermittent virus reactivation from latency and shedding in the vaginal mucosa (VM) causes recurrent genital herpes. While T-cells appear to play a role in controlling virus reactivation and reducing the severity of recurrent genital herpes, the mechanisms for recruiting these T-cells into DRG and VM tissues remain to be fully elucidated. The present study investigates the effect of CXCL9, CXCL10, and CXCL11 T-cell-attracting chemokines on the frequency and function of DRG- and VM-resident CD4+ and CD8+ T cells and its effect on the frequency and severity of recurrent genital herpes. HSV-2 latent-infected guinea pigs were immunized intramuscularly with the HSV-1 RR2 protein (Prime) and subsequently treated intravaginally with the neurotropic adeno-associated virus type 8 (AAV-8) expressing CXCL9, CXCL10, or CXCL11 T-cell-attracting chemokines (Pull). Compared to the RR2 therapeutic vaccine alone, the RR2/CXCL11 prime/pull therapeutic vaccine significantly increased the frequencies of functional tissue-resident (TRM cells) and effector (TEM cells) memory CD4+ and CD8+ T cells in both DRG and VM tissues. This was associated with less virus shedding in the healed genital mucosal epithelium and reduced frequency and severity of recurrent genital herpes. These findings confirm the role of local DRG- and VM-resident CD4+ and CD8+ TRM and TEM cells in reducing virus reactivation shedding and the severity of recurrent genital herpes and propose the novel prime/pull vaccine strategy to protect against recurrent genital herpes. IMPORTANCEThe present study investigates a novel prime/pull therapeutic vaccine strategy to protect against recurrent genital herpes in the guinea pig model. HSV-2 infected guinea pigs were vaccinated using a recombinantly expressed herpes tegument protein-RR2 (prime), followed by intravaginal treatment with the neurotropic adeno-associated virus type 8 (AAV-8) expressing CXCL9, CXCL10, or CXCL11 T-cell-attracting chemokines (pull). The RR2/CXCL11 prime/pull therapeutic vaccine elicited a significant reduction in virus shedding in the vaginal mucosa and decreased the severity and frequency of recurrent genital herpes. This protection was associated with increased frequencies of functional tissue-resident (TRM cells) and effector (TEM cells) memory CD4+ and CD8+ T cells infiltrating latently infected DRG tissues and the healed regions of the vaginal mucosa. These findings shed light on the role of tissue-resident (TRM cells) and effector (TEM cells) memory CD4+ and CD8+ T cells in DRG and vaginal mucosa (VM) tissues in protection against recurrent genital herpes and propose the prime/pull therapeutic vaccine strategy in combating genital herpes. TWEETA therapeutic RR2/CXCL11 prime/pull vaccine reduced recurrent genital herpes more effectively than therapeutic vaccination with a subunit HSV RR2 antigen alone.

immunology↗

bioRxiv2023

Anti-Viral and Anti-Inflammatory Therapeutic Effect of RAGE-Ig Protein Against Multiple SARS-CoV-2 Variants of Concern Demonstrated in K18-hACE2 Mouse and Syrian Golden Hamster Models

SignificanceSARS-CoV-2 Variants of Concern (VOCs) continue to evolve and re-emerge with chronic inflammatory long-COVID sequelae necessitating the development of anti-inflammatory therapeutic molecules. Therapeutic effects of the Receptor for Advanced Glycation End products (RAGE) were reported in many inflammatory diseases. However, a therapeutic effect of the RAGE in COVID-19 has not been reported. In the present study, we investigated whether and how the RAGE-Ig fusion protein would have an anti-viral and anti-inflammatory therapeutic effect in the COVID-19 system. MethodsThe protective therapeutic effect of RAGE-Ig was determined in vitro in K18-hACE2 transgenic mice and Syrian golden hamsters infected with six various VOCs of SARS-CoV-2. The underlying anti-viral mechanism of RAGE-Ig was determined in vitro in SARS-CoV-2-infected human lung epithelial cells (BEAS-2B). ResultsFollowing treatment of K18-hACE2 mice and hamsters infected with various SARS-CoV-2 VOCs with RAGE-Ig, we demonstrated: (i) significant dose-dependent protection (i.e. greater survival, less weight loss, lower virus replication in the lungs); (ii) a reduction of inflammatory macrophages (F4/80+/Ly6C+) and neutrophils (CD11b+/Ly6G+) infiltrating the infected lungs; (iii) a RAGE-Ig dose-dependent increase in the expression of type I interferons (IFN-, and IFN-{beta}) and type III interferon (IFN{lambda}2) and a decrease in the inflammatory cytokines (IL-6 and IL-8) in SARS-CoV-2-infected human lung epithelial cells; and (iv) a dose-dependent decrease in the expression of CD64 (FcgR1) on monocytes and lung epithelial cells from symptomatic COVID-19 patients. ConclusionOur pre-clinical findings revealed type I and III interferons-mediated anti-viral and anti-inflammatory therapeutic effects of RAGE-Ig protein against COVID-19 caused by multiple SARS-CoV-2 VOCs.

immunology↗

bioRxiv2023

A Multi-Epitope/CXCL11 Prime/Pull Coronavirus Mucosal Vaccine Boosts the Frequency and the Function of Lung-Resident CD4+ and CD8+ Memory T Cells and Protects Against COVID-19-like Symptoms and Death Caused by SARS-CoV-2 infection

The pandemic of the coronavirus disease 2019 (COVID-19) has created the largest global health crisis in almost a century. Following exposure to SARS-CoV-2, the virus particles replicate in the lungs, induce a "cytokine storm" and potentially cause life-threatening inflammatory disease. Low frequencies of function SARS-CoV-2-specific CD4+ and CD8+ T cells in the lungs of COVID-19 patients were associated with severe cases of COVID-19. The apparent low level of T cell-attracting CXCL9, CXCL10, and CXCL11 chemokines in infected lungs may not be sufficient enough to assure the sequestration and/or homing of CD4+ and CD8+ T cells from the circulation into infected lungs. We hypothesize that a Coronavirus vaccine strategy that boosts the frequencies of functional SARS-CoV-2-specific CD4+ and CD8+ T cells in the lungs would lead to better protection against SARS-CoV-2 infection, COVID19-like symptoms, and death. In the present study, we designed and pre-clinically tested the safety, immunogenicity, and protective efficacy of a novel multi-epitope//CXCL11 prime/pull mucosal Coronavirus vaccine. This prime/pull vaccine strategy consists of intranasal delivery of a lung-tropic adeno-associated virus type 9 (AAV-9) vector that incorporates highly conserved human B, CD4+ CD8+ cell epitopes of SARS-CoV-2 (prime) and pulling the primed B and T cells into the lungs using the T cell attracting chemokine, CXCL-11 (pull). We demonstrated that immunization of HLA-DR*0101/HLA-A*0201/hACE2 triple transgenic mice with this multi-epitope//CXCL11 prime/pull Coronavirus mucosal vaccine: (i) Increased the frequencies of CD4+ and CD8+ TEM, TCM, and TRM cells in the lungs; and (ii) reduced COVID19-like symptoms, lowered virus replication, and prevented deaths following challenge with SARS-CoV-2. These findings discuss the importance of bolstering the number and function of lung-resident memory CD4+ and CD8+ T cells for better protection against SARS-CoV-2 infection, COVID-19-like symptoms, and death.

immunology↗

bioRxiv2023

High Frequencies of Antiviral Effector Memory TEM Cells and Memory B Cells Mobilized into Herpes Infected Vaginal Mucosa Associated With Protection Against Genital Herpes

Vaginal mucosa-resident anti-viral effector memory B- and T cells appeared to play a crucial role in protection against genital herpes. However, how to mobilize such protective immune cells into the vaginal tissue close to infected epithelial cells remains to be determined. In the present study, we investigate whether and how, CCL28, a major mucosal-associated chemokine, mobilizes effector memory B- and T cells in leading to protecting mucosal surfaces from herpes infection and disease. The CCL28 is a chemoattractant for the CCR10 receptor-expressing immune cells and is produced homeostatically in the human vaginal mucosa (VM). We found the presence of significant frequencies of HSV-specific memory CCR10+CD44+CD8+ T cells, expressing high levels of CCR10 receptor, in herpes-infected asymptomatic (ASYMP) women compared to symptomatic (SYMP) women. A significant amount of the CCL28 chemokine (a ligand of CCR10), was detected in the VM of herpes-infected ASYMP B6 mice, associated with the mobilization of high frequencies of HSV-specific effector memory CCR10+CD44+ CD62L- CD8+ TEM cells and memory CCR10+B220+CD27+ B cells in the VM of HSV-infected asymptomatic mice. In contrast, compared to wild-type (WT) B6 mice, the CCL28 knockout (CCL28(-/-)) mice: (i) Appeared more susceptible to intravaginal infection and re-infection with HSV-2; (ii) Exhibited a significant decrease in the frequencies of HSV-specific effector memory CCR10+CD44+ CD62L- CD8+ TEM cells and of memory CD27+B220+ B cells in the infected VM. The results imply a critical role of the CCL28/CCR10 chemokine axis in the mobilization of anti-viral memory B and T cells within the VM to protect against genital herpes infection and disease.

immunology↗

bioRxiv2023

Cross-Protection Induced by Highly Conserved Human B, CD4+, and CD8+ T Cell Epitopes-Based Coronavirus Vaccine Against Severe Infection, Disease, and Death Caused by Multiple SARS-CoV-2 Variants of Concern

BackgroundThe Coronavirus disease 2019 (COVID-19) pandemic has created one of the largest global health crises in almost a century. Although the current rate of SARS-CoV-2 infections has decreased significantly; the long-term outlook of COVID-19 remains a serious cause of high death worldwide; with the mortality rate still surpassing even the worst mortality rates recorded for the influenza viruses. The continuous emergence of SARS-CoV-2 variants of concern (VOCs), including multiple heavily mutated Omicron sub-variants, have prolonged the COVID-19 pandemic and outlines the urgent need for a next-generation vaccine that will protect from multiple SARS-CoV-2 VOCs. MethodsIn the present study, we designed a multi-epitope-based Coronavirus vaccine that incorporated B, CD4+, and CD8+ T cell epitopes conserved among all known SARS-CoV-2 VOCs and selectively recognized by CD8+ and CD4+ T-cells from asymptomatic COVID-19 patients irrespective of VOC infection. The safety, immunogenicity, and cross-protective immunity of this pan-Coronavirus vaccine were studied against six VOCs using an innovative triple transgenic h-ACE-2-HLA-A2/DR mouse model. ResultsThe Pan-Coronavirus vaccine: (i) is safe; (ii) induces high frequencies of lung-resident functional CD8+ and CD4+ TEM and TRM cells; and (iii) provides robust protection against virus replication and COVID-19-related lung pathology and death caused by six SARS-CoV-2 VOCs: Alpha (B.1.1.7), Beta (B.1.351), Gamma or P1 (B.1.1.28.1), Delta (lineage B.1.617.2) and Omicron (B.1.1.529). Conclusions: A multi-epitope pan-Coronavirus vaccine bearing conserved human B and T cell epitopes from structural and non-structural SARS-CoV-2 antigens induced cross-protective immunity that cleared the virus, and reduced COVID-19-related lung pathology and death caused by multiple SARS-CoV-2 VOCs.

immunology↗

bioRxiv2022

High Frequencies of Phenotypically and Functionally Senescent and Exhausted CD56+CD57+PD-1+ Natural Killer Cells, SARS-CoV-2-Specific Memory CD4+ and CD8+ T cells Associated with Severe Disease in Unvaccinated COVID-19 Patients

Unvaccinated COVID-19 patients display a large spectrum of symptoms, ranging from asymptomatic to severe symptoms, the latter even causing death. Distinct Natural killer (NK) and CD4+ and CD8+ T cells immune responses are generated in COVID-19 patients. However, the phenotype and functional characteristics of NK cells and T-cells associated with COVID-19 pathogenesis versus protection remain to be elucidated. In this study, we compared the phenotype and function of NK cells SARS-CoV-2-specific CD4+ and CD8+ T cells in unvaccinated symptomatic (SYMP) and unvaccinated asymptomatic (ASYMP) COVID-19 patients. The expression of senescent CD57 marker, CD45RA/CCR7differentiation status, exhaustion PD-1 marker, activation of HLA-DR, and CD38 markers were assessed on NK and T cells from SARS-CoV-2 positive SYMP patients, ASYMP patients, and Healthy Donors (HD) using multicolor flow cytometry. We detected significant increases in the expression levels of both exhaustion and senescence markers on NK and T cells from SYMP patients compared to ASYMP patients and HD controls. In SYMP COVID-19 patients, the T cell compartment displays several alterations involving naive, central memory, effector memory, and terminally differentiated T cells. The senescence CD57 marker was highly expressed on CD8+ TEM cells and CD8+ TEMRA cells. Moreover, we detected significant increases in the levels of proinflammatory TNF-, IFN-{gamma}, IL-6, IL-8, and IL-17 cytokines from SYMP COVID-19 patients, compared to ASYMP COVID-19 patients and HD controls. The findings suggest exhaustion and senescence in both NK and T cell compartment is associated with severe disease in critically ill COVID-19 patients. IMPORTANCEUnvaccinated COVID-19 patients display a large spectrum of symptoms, ranging from asymptomatic to severe symptoms, the latter even causing death. Distinct Natural killer (NK) and CD4+ and CD8+ T cells immune responses are generated in COVID-19 patients. In this study, we detected significant increases in the expression levels of both exhaustion and senescence markers on NK and T cells from unvaccinated symptomatic (SYMP) compared to unvaccinated asymptomatic (ASYMP) COVID-19 patients. Moreover, we detected significant increases in the levels of proinflammatory TNF-, IFN-{gamma}, IL-6, IL-8, and IL-17 cytokines from SYMP COVID-19 patients, compared to ASYMP COVID-19 patients. The findings suggest exhaustion and senescence in both NK and T cell compartment is associated with severe disease in critically ill COVID-19 patients. TWEETSignificant exhaustion and senescence in both NK and T cells were detected in unvaccinated symptomatic COVID-19 patients, suggesting a weakness in both innate and adaptive immune systems leads to severe disease in critically ill COVID-19 patients.

immunology↗

bioRxiv2022

A Prime/Pull RR2/CXCL11 Therapeutic Vaccine that Bolsters the Number and Function of Dorsal Root Ganglia Tissue-Resident HSV-Specific CD8+ TRM Cells Protects Latently Infected Guinea Pigs from Recurrent Genital Herpes

Reactivation of herpes simplex virus type 2 (HSV-2) from latently infected dorsal root ganglia (DRG) and subsequent virus shedding in the genital tract trigger recurrent genital herpes. Memory CD8+ T cells play a critical role in preventing HSV-2 reactivation from latently infected DRG, thus reducing recurrent genital lesions. The role of T-cell attracting chemokines in promoting CD8+ T cell protective immunity in recurrent genital herpes remains to be fully elucidated. In this study, we investigated whether and how the CXCL11/CXCR3 pathway affects the frequency and function of DRG-resident CD8+ T cells and the severity of recurrent genital herpes. Latently infected guinea pigs were primed with the HSV-1 RR2 protein, delivered intramuscularly with CpG/Alum adjuvants, and the induced T cells were "pulled" from the periphery into the latently infected DRG using T-cell attracting CXCL11 chemokine, delivered to DRG. In the guinea pigs that received the prime/pull vaccine, we detected a significant increase in both the number and function of tissue-resident IFN-{gamma}+CD103+CD44+CXCR3+CD8+ TRM cells that infiltrated healed sites of the vaginal mucosa (VM) and DRG tissues. This was associated with a significant decrease in virus shedding and a reduction in both the severity and frequency of recurrent genital herpes lesions. In contrast, in the guinea pigs that received the RR2 vaccine alone, we detected fewer functional CD8+ TRM cells and no reduction in the severity of recurrent genital herpes. These findings highlight the role of the CXCL11/CXCR3 chemokine pathway in shaping tissue-resident CD8+ TRM cell protective immunity against recurrent genital herpes. IMPORTANCERecurrent genital herpes is a common sexually transmitted disease worldwide. Currently, no FDA-approved therapeutic vaccines are available. In the present study, we used HSV-2 latently infected guinea pig to investigate a novel therapeutic prime/pull vaccine strategy based on priming T cells systemically, with a recombinantly expressed herpes envelope and tegument protein RR2 and "pulling" primed T cells into the tissues of latently infected ganglia with the T-cell-attracting chemokine, CXCL11. We discovered that this RR2/CXCL11 prime/pull vaccine elicited a significant reduction in virus shedding and a decrease in both the severity and frequency of recurrent genital herpes sores. This protection correlated with increased numbers of functional tissue-resident IFN-{gamma}+CD103+CD44+CXCR3+CD8+ TRM cells that infiltrate healed sites of the VM tissues and DRG. Our findings shed light on the role of TRM cells in protection against recurrent genital herpes and propose the prime/pull therapeutic vaccine as a new strategy against genital herpes. TWEETThe present study presents a novel RR2/CXCL11 prime/pull therapeutic vaccine that elicited a significant reduction in virus shedding and a decrease in both the severity and frequency of recurrent genital herpes sores.

immunology↗

bioRxiv2022

High Frequencies of PD-1+TIM3+TIGIT+CTLA4+ Functionally Exhausted SARS-CoV-2-Specific CD4+ and CD8+ T Cells Associated with Severe Disease in Critically ill COVID-19 Patients

SARS-CoV-2-specific memory T cells that cross-react with common cold coronaviruses (CCCs) are present in both healthy donors and COVID-19 patients. However, whether these cross-reactive T cells play a role in COVID-19 pathogenesis versus protection remain to be fully elucidated. In this study, we characterized cross-reactive SARS-CoV-2-specific CD4+ and CD8+ T cells, targeting genome-wide conserved epitopes in a cohort of 147 non-vaccinated COVID-19 patients, divided into six groups based on the degrees of disease severity. We compared the frequency, phenotype, and function of these SARS-CoV-2-specific CD4+ and CD8+ T cells between severely ill and asymptomatic COVID-19 patients and correlated this with -CCCs and {beta}-CCCs co-infection status. Compared with asymptomatic COVID-19 patients, the severely ill COVID-19 patients and patients with fatal outcomes: (i) Presented a broad leukocytosis and a broad CD4+ and CD8+ T cell lymphopenia; (ii) Developed low frequencies of functional IFN-{gamma}-producing CD134+CD138+CD4+ and CD134+CD138+CD8+ T cells directed toward conserved epitopes from structural, non-structural and regulatory SARS-CoV-2 proteins; (iii) Displayed high frequencies of SARS-CoV-2-specific functionally exhausted PD-1+TIM3+TIGIT+CTLA4+CD4+ and PD-1+TIM3+TIGIT+CTLA4+CD8+ T cells; and (iv) Displayed similar frequencies of co-infections with {beta}-CCCs strains but significantly fewer co-infections with -CCCs strains. Interestingly, the cross-reactive SARS-CoV-2 epitopes that recalled the strongest CD4+ and CD8+ T cell responses in unexposed healthy donors (HD) were the most strongly associated with better disease outcome seen in asymptomatic COVID-19 patients. Our results demonstrate that, the critically ill COVID-19 patients displayed fewer co-infection with -CCCs strain, presented broad T cell lymphopenia and higher frequencies of cross-reactive exhausted SARS-CoV-2-specific CD4+ and CD8+ T cells. In contrast, the asymptomatic COVID-19 patients, appeared to present more co-infections with -CCCs strains, associated with higher frequencies of functional cross-reactive SARS-CoV-2-specific CD4+ and CD8+ T cells. These findings support the development of broadly protective, T-cell-based, multi-antigen universal pan-Coronavirus vaccines. KEY POINTSO_LIA broad lymphopenia and lower frequencies of SARS-CoV-2-specific CD4+ and CD8+ T-cells were associated with severe disease onset in COVID-19 patients. C_LIO_LIHigh frequencies of phenotypically and functionally exhausted SARS-CoV-2-specific CD4+ and CD8+ T cells, co-expressing multiple exhaustion markers, and targeting multiple structural, non-structural, and regulatory SARS-CoV-2 protein antigens, were detected in severely ill COVID-19 patients. C_LIO_LICompared to severely ill COVID-19 patients and to patients with fatal outcomes, the (non-vaccinated) asymptomatic COVID-19 patients presented more functional cross-reactive CD4+ and CD8+ T cells targeting conserved epitopes from structural, non-structural, and regulatory SARS-CoV-2 protein antigens. C_LIO_LIThe cross-reactive SARS-CoV-2 epitopes that recalled the strongest CD4+ and CD8+ T cell responses in unexposed healthy donors (HD) were the most strongly associated with better disease outcomes seen in asymptomatic COVID-19 patients. C_LIO_LICompared to severely ill COVID-19 patients and to patients with fatal outcomes, the (non-vaccinated) asymptomatic COVID-19 patients presented higher rates of co-infection with the -CCCs strains. C_LIO_LICompared to patients with mild or asymptomatic COVID-19, severely ill symptomatic patients and patients with fatal outcomes had more exhausted SARS-CoV-2-speccific CD4+ and CD8+ T cells that preferentially target cross-reactive epitopes that share high identity and similarity with the {beta}-CCCs strains. C_LI

immunology↗