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1.
Cell Rep ; 36(8): 109591, 2021 08 24.
Article in English | MEDLINE | ID: covidwho-1370154

ABSTRACT

The relationship between B cells and CD4 T cells has been carefully studied, revealing a collaborative effort in which B cells promote the activation, differentiation, and expansion of CD4 T cells while the so-called "helper" cells provide signals to B cells, influencing their class switching and fate. Interactions between B cells and CD8 T cells are not as well studied, although CD8 T cells exhibit an accelerated contraction after certain infections in B-cell-deficient mice. Here, we find that B cells significantly enhance primary CD8 T cell responses after vaccination. Moreover, memory CD8 numbers and function are impaired in B-cell-deficient animals, leading to increased susceptibility to bacterial challenge. We also show that interleukin-27 production by B cells contributes to their impact on primary, but not memory, CD8 responses. Better understanding of the interactions between CD8 T cells and B cells may aid in the design of more effective future vaccine strategies.


Subject(s)
B-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , Immunologic Memory , Interleukin-27/immunology , Interleukin-27/metabolism , T-Lymphocytes, Helper-Inducer/immunology , Vaccines, Subunit/immunology , Animals , B-Lymphocytes/metabolism , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/metabolism , COVID-19/immunology , Humans , Lymphocyte Count , Mice , Mice, Inbred C57BL , Receptors, Virus/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Vaccination
2.
J Virol ; 96(15): e0076022, 2022 08 10.
Article in English | MEDLINE | ID: covidwho-1949996

ABSTRACT

Robust population-wide immunity will help to curb the SARS-CoV-2 pandemics. To maintain the immunity at protective levels, the quality and persistence of the immune response elicited by infection or vaccination must be determined. We analyzed the dynamics of B cell response during 12 months following SARS-CoV-2 infection on an individual level. In contrast to antibodies, memory B cells specific for the spike (S) protein persisted at high levels throughout the period. These cells efficiently secreted neutralizing antibodies and correlated with IFN-γ-secreting CD4+ T cells. Interestingly, the CD27-CD21+ intermediate memory B cell phenotype was associated with high B cell receptor avidity and the production of neutralizing antibodies. Vaccination of previously infected individuals triggered a recall response enhancing neutralizing antibody and memory B cell levels. Collectively, our findings provide a detailed insight into the longevity of SARS-CoV-2-infection-induced B cell immunity and highlight the importance of vaccination among previously infected. IMPORTANCE To efficiently maintain immunity against SARS-CoV-2 infection, we must first determine the durability of the immune response following infection or vaccination. Here, we demonstrated that, unlike antibodies, virus-specific memory B cells persist at high levels for at least 12 months postinfection and successfully respond to a secondary antigen challenge. Furthermore, we demonstrated that vaccination of previously infected individuals significantly boosters B cell immunity.


Subject(s)
COVID-19 Vaccines , COVID-19 , Immunologic Memory , Memory B Cells , SARS-CoV-2 , Vaccination , Antibodies, Neutralizing , Antibodies, Viral , CD4-Positive T-Lymphocytes/immunology , COVID-19/immunology , COVID-19 Vaccines/chemistry , COVID-19 Vaccines/immunology , Humans , Interferon-gamma/immunology , Memory B Cells/cytology , Memory B Cells/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Time Factors
3.
J Virol ; 96(6): e0187321, 2022 03 23.
Article in English | MEDLINE | ID: covidwho-1759293

ABSTRACT

Given the current coronavirus disease 2019 (COVID-19) pandemic, coinfection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza A virus (IAV) is a major concern for public health. However, the immunopathogenic events occurring with coinfections of SARS-CoV-2 and IAV remain unclear. Here, we report the pathogenic and immunological consequences of SARS-CoV-2 and IAV H1N1 coinfection in the K18-hACE2 transgenic mouse model. Compared with a single infection with SARS-CoV-2 or IAV, coinfections not only prolonged the primary virus infection period but also increased immune cell infiltration and inflammatory cytokine levels in bronchoalveolar lavage fluid leading to severe pneumonia and lung damage. Moreover, coinfections caused severe lymphopenia in peripheral blood, resulting in reduced total IgG, neutralizing antibody titers, and CD4+ T cell responses against each virus. This study sheds light on the immunopathogenesis of SARS-CoV-2 and IAV coinfection, which may guide the development of effective therapeutic strategies for the treatment of patients coinfected with these viruses. IMPORTANCE The cocirculation of influenza virus merging with the COVID-19 pandemic raises a potentially severe threat to public health. Recently, increasing numbers of SARS-CoV-2 and influenza virus coinfection have been reported from many countries. It is a worrisome issue that SARS-CoV-2 coinfection with other pathogens may worsen the clinical outcome and severity of COVID-19 and increase fatality. Here, we evaluated SARS-CoV-2 and IAV coinfection using the K18-hACE2 mouse model. Coinfected mice exhibited increased mortality with prolonged IAV shedding. Furthermore, coinfected mice showed a higher level of cytokines and chemokines than a single infection condition. Interestingly, our data show that coinfected mice showed significantly fewer virus-specific and neutralizing antibodies than the mice with a single infection. Overall, this study suggests that coinfection aggravates viral pathology by impaired neutralizing antibody response.


Subject(s)
COVID-19 , Coinfection , Influenza A Virus, H1N1 Subtype , Orthomyxoviridae Infections , SARS-CoV-2 , Animals , Antibodies, Neutralizing , CD4-Positive T-Lymphocytes/immunology , COVID-19/immunology , Coinfection/immunology , Disease Models, Animal , Humans , Influenza A Virus, H1N1 Subtype/immunology , Mice , Orthomyxoviridae Infections/immunology , SARS-CoV-2/immunology , Severity of Illness Index
4.
Microbiol Spectr ; 10(1): e0169521, 2022 02 23.
Article in English | MEDLINE | ID: covidwho-1752774

ABSTRACT

Global control of COVID-19 will require the deployment of vaccines capable of inducing long-term protective immunity against SARS-CoV-2 variants. In this report, we describe an adjuvanted subunit candidate vaccine that affords elevated, sustained, and cross-variant SARS-CoV-2 neutralizing antibodies (NAbs) in multiple animal models. Alhydroxiquim-II is a Toll-Like Receptor (TLR) 7/8 small-molecule agonist chemisorbed on aluminum hydroxide (Alhydrogel). Vaccination with Alhydroxiquim-II combined with a stabilized, trimeric form of the SARS-CoV-2 spike protein (termed CoVac-II) resulted in high-titer NAbs in mice, with no decay in responses over an 8-month period. NAbs from sera of CoVac-II-immunized mice, horses and rabbits were broadly neutralizing against SARS-CoV-2 variants. Boosting long-term CoVac-II-immunized mice with adjuvanted spike protein from the Beta variant markedly increased levels of NAb titers against multiple SARS-CoV-2 variants; notably, high titers against the Delta variant were observed. These data strongly support the clinical assessment of Alhydroxiquim-II-adjuvanted spike proteins to protect against SARS-CoV-2 variants of concern. IMPORTANCE There is an urgent need for next-generation COVID-19 vaccines that are safe, demonstrate high protective efficacy against SARS-CoV-2 variants and can be manufactured at scale. We describe a vaccine candidate (CoVac-II) that is based on stabilized, trimeric spike antigen produced in an optimized, scalable and chemically defined production process. CoVac-II demonstrates strong and persistent immunity after vaccination of mice, and is highly immunogenic in multiple animal models, including rabbits and horses. We further show that prior immunity can be boosted using a recombinant spike antigen from the Beta variant; importantly, plasma from boosted mice effectively neutralize multiple SARS-CoV-2 variants in vitro, including Delta. The strong humoral and Th1-biased immunogenicity of CoVac-II is driven by use of Alhydroxiquim-II (AHQ-II), the first adjuvant in an authorized vaccine that acts through the dual Toll-like receptor (TLR)7 and TLR8 pathways, as part of the Covaxin vaccine. Our data suggest AHQ-II/spike protein combinations could constitute safe, affordable, and mass-manufacturable COVID-19 vaccines for global distribution.


Subject(s)
Antibodies, Neutralizing/biosynthesis , Antibodies, Viral/biosynthesis , COVID-19 Vaccines/immunology , SARS-CoV-2/immunology , Animals , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , CD4-Positive T-Lymphocytes/immunology , Horses , Mice , Rabbits , T-Lymphocytes/immunology
5.
Front Immunol ; 13: 835686, 2022.
Article in English | MEDLINE | ID: covidwho-1742218

ABSTRACT

Angiotensin converting enzyme-2 (ACE2) and associated proteins play a pivotal role in various physiological and pathological events, such as immune activation, inflammation, gut barrier maintenance, intestinal stem cell proliferation, and apoptosis. Although many of these clinical events are quite significant in SIV/HIV infection, expression profiling of these proteins has not been well reported. Considering the different pathological consequences in the gut after HIV infection, we hypothesized that the expression of ACE2 and associated proteins of the Renin-angiotensin system (RAS) could be compromised after SIV/HIV infection. We quantified the gene expression of ACE2 as well as AGTR1/2, ADAM17, and TMPRSS2, and compared between SIV infected and uninfected rhesus macaques (Macaca mulatta; hereafter abbreviated RMs). The gene expression analysis revealed significant downregulation of ACE2 and upregulation of AGTR2 and inflammatory cytokine IL-6 in the gut of infected RMs. Protein expression profiling also revealed significant upregulation of AGTR2 after infection. The expression of ACE2 in protein level was also decreased, but not significantly, after infection. To understand the entirety of the process in newly regenerated epithelial cells, a global transcriptomic study of enteroids raised from intestinal stem cells was performed. Interestingly, most of the genes associated with the RAS, such as DPP4, MME, ANPEP, ACE2, ENPEP, were found to be downregulated in SIV infection. HNFA1 was found to be a key regulator of ACE2 and related protein expression. Jejunum CD4+ T cell depletion and increased IL-6 mRNA, MCP-1 and AGTR2 expression may signal inflammation, monocyte/macrophage accumulation and epithelial apoptosis in accelerating SIV pathogenesis. Overall, the findings in the study suggested a possible impact of SIV/HIV infection on expression of ACE2 and RAS-associated proteins resulting in the loss of gut homeostasis. In the context of the current COVID-19 pandemic, the outcome of SARS-CoV-2 and HIV co-infection remains uncertain and needs further investigation as the significance profile of ACE2, a viral entry receptor for SARS-CoV-2, and its expression in mRNA and protein varied in the current study. There is a concern of aggravated SARS-CoV-2 outcomes due to possible serious pathological events in the gut resulting from compromised expression of RAS- associated proteins in SIV/HIV infection.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , CD4-Positive T-Lymphocytes/immunology , Jejunum/metabolism , Simian Acquired Immunodeficiency Syndrome/metabolism , Simian Immunodeficiency Virus/physiology , Animals , Cells, Cultured , Cytokines/metabolism , Dipeptidyl Peptidase 4/metabolism , Gene Expression Regulation , Humans , Inflammation Mediators , Jejunum/pathology , Macaca mulatta , Receptor, Angiotensin, Type 2/metabolism
6.
Front Immunol ; 12: 794638, 2021.
Article in English | MEDLINE | ID: covidwho-1731769

ABSTRACT

CCR5 plays a central role in infectious disease, host defense, and cancer progression, thereby making it an ideal target for therapeutic development. Notably, CCR5 is the major HIV entry co-receptor, where its surface density correlates with HIV plasma viremia. The level of CCR5 receptor occupancy (RO) achieved by a CCR5-targeting therapeutic is therefore a critical predictor of its efficacy. However, current methods to measure CCR5 RO lack sensitivity, resulting in high background and overcalculation. Here, we report on two independent, flow cytometric methods of calculating CCR5 RO using the anti-CCR5 antibody, Leronlimab. We show that both methods led to comparable CCR5 RO values, with low background on untreated CCR5+CD4+ T cells and sensitive measurements of occupancy on both blood and tissue-resident CD4+ T cells that correlated longitudinally with plasma concentrations in Leronlimab-treated macaques. Using these assays, we found that Leronlimab stabilized cell surface CCR5, leading to an increase in the levels of circulating and tissue-resident CCR5+CD4+ T cells in vivo in Leronlimab-treated macaques. Weekly Leronlimab treatment in a chronically SIV-infected macaque led to increased CCR5+CD4+ T cells levels and fully suppressed plasma viremia, both concomitant with full CCR5 RO on peripheral blood CD4+ T cells, demonstrating that CCR5+CD4+ T cells were protected from viral replication by Leronlimab binding. Finally, we extended these results to Leronlimab-treated humans and found that weekly 700 mg Leronlimab led to complete CCR5 RO on peripheral blood CD4+ T cells and a statistically significant increase in CCR5+CD4+ T cells in peripheral blood. Collectively, these results establish two RO calculation methods for longitudinal monitoring of anti-CCR5 therapeutic antibody blockade efficacy in both macaques and humans, demonstrate that CCR5+CD4+ T cell levels temporarily increase with Leronlimab treatment, and facilitate future detailed investigations into the immunological impacts of CCR5 inhibition in multiple pathophysiological processes.


Subject(s)
Antibodies, Monoclonal, Humanized/therapeutic use , CD4-Positive T-Lymphocytes/immunology , COVID-19/drug therapy , Flow Cytometry/methods , HIV Antibodies/therapeutic use , HIV Infections/drug therapy , HIV-1/physiology , Receptors, CCR5/metabolism , SARS-CoV-2/physiology , Simian Acquired Immunodeficiency Syndrome/drug therapy , Simian Immunodeficiency Virus/physiology , Animals , CD4 Lymphocyte Count , Female , Humans , Primates , Protein Binding , Receptors, CCR5/immunology , Treatment Outcome
7.
Front Immunol ; 12: 804808, 2021.
Article in English | MEDLINE | ID: covidwho-1731770

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing the coronavirus disease 2019 (COVID-19) pandemic is a serious global threat until we identify the effective preventive and therapeutic strategies. SARS-CoV-2 infection is characterized by various immunopathological consequences including lymphocyte activation and dysfunction, lymphopenia, cytokine storm, increased level of neutrophils, and depletion and exhaustion of lymphocytes. Considering the low level of antibody-mediated protection during coronavirus infection, understanding the role of T cell for long-term protection is decisive. Both CD4+ and CD8+ T cell response is imperative for cell-mediated immune response during COVID-19. However, the level of CD8+ T cell response reduced to almost half as compared to CD4+ after 6 months of infection. The long-term protection is mediated via generation of immunological memory response during COVID-19. The presence of memory CD4+ T cells in all the severely infected and recovered individuals shows that the memory response is predominated by CD4+ T cells. Prominently, the antigen-specific CD4+ and CD8+ T cells are specifically observed during day 0 to day 28 in COVID-19-vaccinated individuals. However, level of antigen-specific T memory cells in COVID-19-vaccinated individuals defines the long-term protection against forthcoming outbreaks of SARS-CoV-2.


Subject(s)
CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , Immunologic Memory/immunology , /immunology , Animals , Cytokine Release Syndrome/immunology , Humans
8.
J Immunol Methods ; 502: 113230, 2022 03.
Article in English | MEDLINE | ID: covidwho-1720358

ABSTRACT

Innate immune mechanisms are central players in response to the binding of pathogens to pattern-recognition receptors providing a crucial initial block on viral replication. Moreover, innate immune response mobilizes cells of the cellular-mediated immune system, which develop into effector cells that promote viral clearance. Here, we observed circulating leukocyte T cell response in healthy subjects, COVID-19 infected, and in healthy vaccinated subjects. We found a significant CD8+ T cells (p < 0,05) decrease and an augmented CD4+/CD8+ ratio (p < 0,05) in COVID-19 infected group compared with vaccinated subjects. In addition, healthy vaccinated subjects have a significant increased expression of CD8+ T cells, and a reduction of CD4+/CD8+ ratio with respect to subjects previously COVID-19 infected. Central Memory and Terminal Effector Memory cells (TEMRA) increased after vaccine but not among groups.


Subject(s)
CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19 Vaccines/immunology , COVID-19/immunology , /immunology , Adult , Aged , CD4-CD8 Ratio , COVID-19/blood , COVID-19/prevention & control , COVID-19/virology , COVID-19 Vaccines/administration & dosage , Case-Control Studies , Cross-Sectional Studies , Female , Healthy Volunteers , Humans , Immunity, Innate , Immunogenicity, Vaccine , Immunophenotyping , Male , Middle Aged , SARS-CoV-2/immunology , Vaccination
9.
Front Immunol ; 12: 820126, 2021.
Article in English | MEDLINE | ID: covidwho-1715000

ABSTRACT

This study aims to assess the immunological response and impact on virological control of the mRNA vaccines for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among people living with HIV (PLWH). In this single-center observational study, all PLWH were offered vaccination with mRNA1273 or BNT162b2. Both anti-N and anti-S1-receptor binding domain (RBD) antibodies were measured together with HIV-1 RNA levels after the first dose (M0) and then at 1 (M1), 2 (M2) and 6 (M6) months later. A total of 131 individuals (median age: 54 years [IQR: 47.0-60.5]; male: 70.2%; median baseline CD4 T-cell: 602/µl [IQR 445.0-825.5]; median nadir CD4 T-cells 223/µl [IQR 111.0-330.0]) were included. All participants were positive for anti-RBD antibodies at 30 days, 60 days and 6 months after the first dose, with no statistical difference between those with HIV-1 RNA below or >20 copies/ml. HIV-1 RNA data were collected for 128 patients at baseline and 30 days after the first dose; for 124 individuals, 30 days after the second dose; and for 83 patients, 6 months after the first dose. Nineteen (14.8%) of 128 had detectable HIV-1 RNA (>20 copies/ml) at M0, 13/128 (10.2%) at M1 (among which 5 were newly detectable), 15/124 (12.1%) at M2 (among which 5 were newly detectable), and 8/83 (9.6%) at M6. No serious adverse effects were reported. All participants elicited antibodies after two doses of mRNA vaccines, with only a minor impact on HIV-1 RNA levels over a 6-month period.


Subject(s)
/immunology , CD4-Positive T-Lymphocytes/immunology , COVID-19/immunology , HIV Infections/immunology , HIV-1/physiology , RNA, Viral/analysis , SARS-CoV-2/physiology , Adult , Aged , Antibodies, Viral/blood , Antibody Formation , Coronavirus Nucleocapsid Proteins/immunology , Female , Humans , Immunity, Heterologous , Male , Middle Aged , Phosphoproteins/immunology , Spike Glycoprotein, Coronavirus/immunology , Vaccination
11.
Front Immunol ; 13: 817905, 2022.
Article in English | MEDLINE | ID: covidwho-1699973

ABSTRACT

The duration of humoral and cellular immune memory following SARS-CoV-2 infection in populations in least developed countries remains understudied but is key to overcome the current SARS-CoV-2 pandemic. Sixty-four Cambodian individuals with laboratory-confirmed infection with asymptomatic or mild/moderate clinical presentation were evaluated for Spike (S)-binding and neutralizing antibodies and antibody effector functions during acute phase of infection and at 6-9 months follow-up. Antigen-specific B cells, CD4+ and CD8+ T cells were characterized, and T cells were interrogated for functionality at late convalescence. Anti-S antibody titers decreased over time, but effector functions mediated by S-specific antibodies remained stable. S- and nucleocapsid (N)-specific B cells could be detected in late convalescence in the activated memory B cell compartment and are mostly IgG+. CD4+ and CD8+ T cell immune memory was maintained to S and membrane (M) protein. Asymptomatic infection resulted in decreased antibody-dependent cellular cytotoxicity (ADCC) and frequency of SARS-CoV-2-specific CD4+ T cells at late convalescence. Whereas anti-S antibodies correlated with S-specific B cells, there was no correlation between T cell response and humoral immune memory. Hence, all aspects of a protective immune response are maintained up to nine months after SARS-CoV-2 infection and in the absence of re-infection.


Subject(s)
Antibodies, Neutralizing/blood , Antibodies, Viral/blood , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , Immunologic Memory/immunology , SARS-CoV-2/immunology , B-Lymphocytes/immunology , COVID-19/pathology , Cambodia , Coronavirus Nucleocapsid Proteins/immunology , Humans , Immunity, Cellular/immunology , Immunity, Humoral/immunology , Phosphoproteins/immunology , Spike Glycoprotein, Coronavirus/immunology
12.
Front Immunol ; 12: 813300, 2021.
Article in English | MEDLINE | ID: covidwho-1690445

ABSTRACT

Background: The presentation of SARS-CoV-2 infection varies from asymptomatic to severe COVID-19. Similarly, high variability in the presence, titre and duration of specific antibodies has been reported. While some host factors determining these differences, such as age and ethnicity have been identified, the underlying molecular mechanisms underpinning these differences remain poorly defined. Methods: We analysed serum and PBMC from 17 subjects with a previous PCR-confirmed SARS-CoV-2 infection and 10 unexposed volunteers following the first wave of the pandemic, in the UK. Anti-NP IgG and neutralising antibodies were measured, as well as a panel of infection and inflammation related cytokines. The virus-specific T cell response was determined by IFN-γ ELISPOT and flow cytometry after overnight incubation of PBMCs with pools of selected SARS-CoV-2 specific peptides. Results: Seven of 17 convalescent subjects had undetectable levels of anti-NP IgG, and a positive correlation was shown between anti-NP IgG levels and the titre of neutralising antibodies (IC50). In contrast, a discrepancy was noted between antibody levels and T cell IFN-γ production by ELISpot following stimulation with specific peptides. Among the analysed cytokines, ß-NGF and IL-1α levels were significantly different between anti-NP positive and negative subjects, and only ß-NGF significantly correlated with anti-NP positivity. Interestingly, CD4+ T cells of anti-NP negative subjects expressed lower amounts of the ß-NGF-specific receptor TrkA. Conclusions: Our results suggest that the ß-NGF/TrkA signalling pathway is associated with the production of anti-NP specific antibody in mild SARS-CoV-2 infection and the mechanistic regulation of this pathway in COVID-19 requires further investigation.


Subject(s)
Antibodies, Anti-Idiotypic/immunology , COVID-19/immunology , Immunoglobulin G/immunology , Nerve Growth Factor/immunology , Nucleoproteins/immunology , Receptor, trkA/immunology , Signal Transduction/immunology , Animals , Antibodies, Viral/immunology , CD4-Positive T-Lymphocytes/immunology , Cell Line , Chlorocebus aethiops , Cytokines/immunology , Humans , Inflammation/immunology , SARS-CoV-2/immunology , Vero Cells
13.
Life Sci Alliance ; 5(6)2022 06.
Article in English | MEDLINE | ID: covidwho-1689580

ABSTRACT

SARS-CoV-2 vaccination has proven effective in inducing an immune response in healthy individuals and is progressively us allowing to overcome the pandemic. Recent evidence has shown that response to vaccination in some vulnerable patients may be diminished, and it has been proposed a booster dose. We tested the kinetic of development of serum antibodies to the SARS-CoV-2 Spike protein, their neutralizing capacity, the CD4 and CD8 IFN-γ T-cell response in 328 subjects, including 131 immunocompromised individuals (cancer, rheumatologic, and hemodialysis patients), 160 health-care workers (HCW) and 37 subjects older than 75 yr, after vaccination with two or three doses of mRNA vaccines. We stratified the patients according to the type of treatment. We found that immunocompromised patients, depending on the type of treatment, poorly respond to SARS-CoV-2 mRNA vaccines. However, an additional booster dose of vaccine induced a good immune response in almost all of the patients except those receiving anti-CD20 antibody. Similarly to HCW, previously infected and vaccinated immunocompromised individuals demonstrate a stronger SARS-CoV-2-specific immune response than those who are vaccinated without prior infection.


Subject(s)
COVID-19 Vaccines/immunology , Immunocompromised Host/immunology , T-Lymphocytes/immunology , /immunology , Aged , Antibodies, Neutralizing/immunology , B-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , Humans , Immunization, Secondary , Middle Aged , Neoplasms/immunology , Renal Dialysis
14.
Mol Cells ; 44(6): 401-407, 2021 Jun 30.
Article in English | MEDLINE | ID: covidwho-1687545

ABSTRACT

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19), which is an ongoing pandemic disease. SARS-CoV-2-specific CD4+ and CD8+ T-cell responses have been detected and characterized not only in COVID-19 patients and convalescents, but also unexposed individuals. Here, we review the phenotypes and functions of SARS-CoV-2-specific T cells in COVID-19 patients and the relationships between SARS-CoV-2-specific T-cell responses and COVID-19 severity. In addition, we describe the phenotypes and functions of SARS-CoV-2-specific memory T cells after recovery from COVID-19 and discuss the presence of SARS-CoV-2-reactive T cells in unexposed individuals and SARS-CoV-2-specific T-cell responses elicited by COVID-19 vaccines. A better understanding of T-cell responses is important for effective control of the current COVID-19 pandemic.


Subject(s)
Antibodies, Neutralizing/biosynthesis , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , Immunity, Cellular , SARS-CoV-2/pathogenicity , Antibodies, Viral/biosynthesis , CD4-Positive T-Lymphocytes/classification , CD4-Positive T-Lymphocytes/virology , CD8-Positive T-Lymphocytes/classification , CD8-Positive T-Lymphocytes/virology , COVID-19/pathology , COVID-19/prevention & control , COVID-19/virology , COVID-19 Vaccines/administration & dosage , Convalescence , Cytokines/biosynthesis , Cytotoxicity, Immunologic , Host-Pathogen Interactions/immunology , Humans , Immunity, Humoral , Immunologic Memory , Immunophenotyping , SARS-CoV-2/immunology , Severity of Illness Index
15.
Front Immunol ; 13: 816220, 2022.
Article in English | MEDLINE | ID: covidwho-1686484

ABSTRACT

SARS-CoV-2 variants of concern (VOCs) can trigger severe endemic waves and vaccine breakthrough infections (VBI). We analyzed the cellular and humoral immune response in 8 patients infected with the alpha variant, resulting in moderate to fatal COVID-19 disease manifestation, after double mRNA-based anti-SARS-CoV-2 vaccination. In contrast to the uninfected vaccinated control cohort, the diseased individuals had no detectable high-avidity spike (S)-reactive CD4+ and CD8+ T cells against the alpha variant and wild type (WT) at disease onset, whereas a robust CD4+ T-cell response against the N- and M-proteins was generated. Furthermore, a delayed alpha S-reactive high-avidity CD4+ T-cell response was mounted during disease progression. Compared to the vaccinated control donors, these patients also had lower neutralizing antibody titers against the alpha variant at disease onset. The delayed development of alpha S-specific cellular and humoral immunity upon VBI indicates reduced immunogenicity against the S-protein of the alpha VOC, while there was a higher and earlier N- and M-reactive T-cell response. Our findings do not undermine the current vaccination strategies but underline a potential need for the inclusion of VBI patients in alternative vaccination strategies and additional antigenic targets in next-generation SARS-CoV-2 vaccines.


Subject(s)
/immunology , Antibodies, Neutralizing/blood , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19 Vaccines/immunology , COVID-19/immunology , Adult , Aged , Aged, 80 and over , Antibodies, Viral/blood , Antibody Affinity/immunology , COVID-19/mortality , Coronavirus M Proteins/immunology , Coronavirus Nucleocapsid Proteins/immunology , Female , Humans , Male , Middle Aged , Phosphoproteins/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Vaccination
16.
Eur Rev Med Pharmacol Sci ; 26(2): 695-709, 2022 Jan.
Article in English | MEDLINE | ID: covidwho-1675568

ABSTRACT

In 2009, obesity was identified for the first time as a risk factor for increased disease severity and mortality in patients infected with the H1N1 influenza A virus. During the current COVID-19 pandemic, overweight and obesity have been described as independent risk factors of disease severity and mortality due to COVID-19. Excess visceral fat is associated with systemic chronic microinflammation, changes in adipokine release, and oxidative stress. These disturbances result in an impaired immune response, including dysfunction in lymphocyte action and antibody production. Moreover, obesity is a cause of endothelial dysfunction, pro-coagulation state, and enhanced expression of angiotensin-converting enzyme 2 (ACE-2), which contributes to the infection itself and the severity of the disease. We analyzed both the impact of obesity on the severity of COVID-19 and the potential mechanism that influences this severity. Moreover, we discuss the effect of obesity complications on the severity of disease and mortality of patients with COVID-19. Furthermore, we summarize the effectiveness of COVID-19 vaccination in patients with obesity. Finally, we analyzed the effect of the COVID-19 pandemic on mood disturbances and emotional eating and, as a consequence, the development of obesity or an increase in its severity. In summary, the studies conducted during the COVID-19 pandemic indicate that effective obesity treatment should be initiated at once. In addition, the data confirm the need to organize efficient obesity treatment systems for the sake of not only the individual but also society.


Subject(s)
COVID-19/pathology , Influenza, Human/pathology , Obesity/complications , Adipokines/metabolism , Angiotensin-Converting Enzyme 2/metabolism , CD4-Positive T-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/metabolism , COVID-19/complications , COVID-19/epidemiology , COVID-19/mortality , Humans , Influenza A Virus, H1N1 Subtype/isolation & purification , Influenza, Human/complications , Influenza, Human/epidemiology , Meta-Analysis as Topic , Obesity/epidemiology , Oxidative Stress , Pandemics , Risk Factors , Severity of Illness Index , Survival Analysis , TOR Serine-Threonine Kinases/metabolism
17.
J Immunol ; 208(5): 1001-1005, 2022 03 01.
Article in English | MEDLINE | ID: covidwho-1674946

ABSTRACT

Advanced age is a main risk factor for severe COVID-19. However, low vaccination efficacy and accelerated waning immunity have been reported in this age group. To elucidate age-related differences in immunogenicity, we analyzed human cellular, serological, and salivary SARS-CoV-2 spike glycoprotein-specific immune responses to the BNT162b2 COVID-19 vaccine in old (69-92 y) and middle-aged (24-57 y) vaccinees compared with natural infection (COVID-19 convalescents, 21-55 y of age). Serological humoral responses to vaccination excee-ded those of convalescents, but salivary anti-spike subunit 1 (S1) IgA and neutralizing capacity were less durable in vaccinees. In old vaccinees, we observed that pre-existing spike-specific CD4+ T cells are associated with efficient induction of anti-S1 IgG and neutralizing capacity in serum but not saliva. Our results suggest pre-existing SARS-CoV-2 cross-reactive CD4+ T cells as a predictor of an efficient COVID-19 vaccine-induced humoral immune response in old individuals.


Subject(s)
Aging/immunology , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , CD4-Positive T-Lymphocytes/immunology , SARS-CoV-2/immunology , Adult , Age Factors , Aged , Aged, 80 and over , COVID-19/immunology , Female , Humans , Immunoglobulin A/blood , Immunoglobulin A/immunology , Immunoglobulin G/blood , Immunoglobulin G/immunology , Male , Middle Aged , Nursing Homes , Saliva/immunology , Spike Glycoprotein, Coronavirus/immunology , Vaccination , Young Adult
18.
Front Immunol ; 12: 755891, 2021.
Article in English | MEDLINE | ID: covidwho-1674329

ABSTRACT

The immune response promoted by SARS-CoV-2 vaccination is relevant to develop novel vaccines and optimized prevention strategies. We analyzed the adaptive immunity in healthy donors (HD) and convalescent individuals (CD), before and after administering BNT162b2 vaccine. Our results revealed specific changes in CD4+ T cell reactivity profile in vaccinated HD and CD, with an increase in S1 and S2 positive individuals, proportionally higher for S2. On the contrary, NCAP reactivity observed in HD and CD patients was no longer detectable after vaccination. Despite the substantial antibody response in CD, MPro-derived peptides did not elicit CD4+ lymphocyte activation in our assay in either condition. HD presented an increment in anti-S and anti-RBD IgG after first dose vaccination, which increased after the second vaccination. Conversely, anti-S and anti-RBD IgG and IgA titers increased in already positive CD after first dose administration, remaining stable after second dose inoculation. Interestingly, we found a strong significant correlation between S1-induced CD4+ response and anti-S IgA pre-vaccination, which was lost after vaccine administration.


Subject(s)
/immunology , CD4-Positive T-Lymphocytes/immunology , COVID-19/immunology , SARS-CoV-2/physiology , Adult , Cells, Cultured , Convalescence , Female , Healthy Volunteers , Humans , Immunization, Secondary , Immunoglobulin A/metabolism , Immunoglobulin G/metabolism , Male , Middle Aged , Spike Glycoprotein, Coronavirus/immunology , T-Cell Antigen Receptor Specificity , Vaccination
19.
Nat Immunol ; 23(3): 380-385, 2022 03.
Article in English | MEDLINE | ID: covidwho-1671602

ABSTRACT

Delayed dosing intervals are a strategy to immunize a greater proportion of the population. In an observational study, we compared humoral and cellular responses in health care workers receiving two doses of BNT162b2 (Pfizer-BioNTech) vaccine at standard (3- to 6-week) and delayed (8- to 16-week) intervals. In the delayed-interval group, anti-receptor-binding domain antibody titers were significantly enhanced compared to the standard-interval group. The 50% plaque reduction neutralization test (PRNT50) and PRNT90 titers against wild-type (ancestral) severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and Alpha, Beta and Delta variants were higher in the delayed-interval group. Spike-specific polyfunctional CD4+ and CD8+ T cells expressing interferon-γ and interleukin-2 were comparable between the two groups. Here, we show that the strategy of delaying second doses of mRNA vaccination may lead to enhanced humoral immune responses, including improved virus neutralization against wild-type and variant SARS-CoV-2 viruses. This finding has potentially important implications as vaccine implementation continues across a greater proportion of the global population.


Subject(s)
/immunology , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , SARS-CoV-2/physiology , Adult , Cells, Cultured , Female , Humans , Immunity, Humoral , Immunization, Secondary , Interferon-gamma/metabolism , Interleukin-2/metabolism , Male , Middle Aged , Vaccination
20.
Front Immunol ; 12: 799896, 2021.
Article in English | MEDLINE | ID: covidwho-1662583

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection results in rapid T lymphocytopenia and functional impairment of T cells. The underlying mechanism, however, remains incompletely understood. In this study, we focused on characterizing the phenotype and kinetics of T-cell subsets with mitochondrial dysfunction (MD) by multicolor flow cytometry and investigating the association between MD and T-cell functionality. While 73.9% of study subjects displayed clinical lymphocytopenia upon hospital admission, a significant reduction of CD4 or CD8 T-cell frequency was found in all asymptomatic, symptomatic, and convalescent cases. CD4 and CD8 T cells with increased MD were found in both asymptomatic and symptomatic patients within the first week of symptom onset. Lower proportion of memory CD8 T cell with MD was found in severe patients than in mild ones at the stage of disease progression. Critically, the frequency of T cells with MD in symptomatic patients was preferentially associated with CD4 T-cell loss and CD8 T-cell hyperactivation, respectively. Patients bearing effector memory CD4 and CD8 T cells with the phenotype of high MD exhibited poorer T-cell responses upon either phorbol 12-myristate-13-acetate (PMA)/ionomycin or SARS-CoV-2 peptide stimulation than those with low MD. Our findings demonstrated an MD-associated mechanism underlying SARS-CoV-2-induced T lymphocytopenia and functional impairment during the acute phase of infection.


Subject(s)
COVID-19/complications , Lymphopenia/complications , Lymphopenia/etiology , Mitochondrial Diseases/etiology , Adult , Aged , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19/drug therapy , COVID-19/immunology , Female , Humans , Immunologic Memory/immunology , Ionomycin/therapeutic use , Lymphopenia/immunology , Male , Middle Aged , Mitochondria/immunology , Mitochondrial Diseases/immunology , Phosphorylcholine/analogs & derivatives , Phosphorylcholine/therapeutic use , Polymethacrylic Acids/therapeutic use
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