scholarly journals Immune responses following third COVID-19 vaccination are reduced in patients with hematologic malignancies compared to patients with solid cancer

2021 ◽  
Author(s):  
Annika Fendler ◽  
Scott T.C. Shepherd ◽  
Lewis Au ◽  
Katalin A. Wilkinson ◽  
Mary Wu ◽  
...  
Keyword(s):  
T Cell ◽  
Vaccine Dose ◽  
T Cell Responses ◽  
Hematologic Malignancies ◽  
Solid Cancer ◽  
Vaccine Responses ◽  
Patients With Cancer ◽  
Cell Responses ◽  
The Third ◽  
The Impact

Abstract Not all patients with cancer, in particular those with hematogic malignancies, develop functional immunity against SARS-CoV-2 variants of concern (VOC) following COVID-19 vaccines. Durability of vaccine-induced immunity after two doses and the impact of a third dose were evaluated in CAPTURE (NCT03226886), a longitudinal prospective cohort study of vaccine responses in patients with cancer. In evaluating 316 patients, at a median of 111 days following two doses of either BNT16b2 or ChadOX, we observed a time-dependant decline in neutralising antibody titres (NAbT) in a proportion of patients, where NAbTs became undetectable against Delta and Beta in 17% and 15% of patients, respectively. Vaccine-induced T cell responses declined in 44% of patients. Patients with breakthrough infections following two vaccines doses were characterised by absent/low NAbT to Delta prior to infection. Administration of the third vaccine dose boosted NAb responses against VOC in the majority of patients with cancer, especially those with solid cancer. In patients with hematologic malignancies who had undetectable NAbT against Delta after two vaccine doses, 54% did not develop NAb against both Beta and Delta following the third dose. Third vaccine dose boosted T cell responses were boosted in patients with both solid and hematologic malignancies. These results provide critical information on vaccine responses in patients with cancer, especially against VOCs and support widespread access to a third COVID-19 vaccination in this patient group.

A Randomized Trial of One Vs. Two Doses of Influenza Vaccine Following Allogeneic Transplantation

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1896-1896
Author(s):  
Nicole Karras ◽  
Wendy Sessions ◽  
Bruce R. Blazar ◽  
John E. Wagner ◽  
Michael R. Verneris
Keyword(s):  
Multivariate Analysis ◽  
Stem Cell ◽  
T Cell ◽  
Influenza Vaccine ◽  
Research Funding ◽  
Vaccine Dose ◽  
T Cell Responses ◽  
Steroid Use ◽  
Vaccine Responses ◽  
Cell Responses

Abstract Abstract 1896 Following hematopoietic stem cell transplantation (HSCT) influenza infections can be potentially life threatening. Prior studies demonstrate that following HSCT, the influenza vaccine is relatively ineffective at inducing influenza specific immunity—especially early after transplant. Additionally, the effectiveness of the annual vaccine depends on recipient age, immune competence and antigenic potential of the three strains included. We hypothesized that a second vaccine dose, as is standard of care in vaccine naïve pediatric patients, might improve vaccine specific immune responses in patients following allogeneic HSCT. During the 2010 influenza season, we conducted a clinical trial where patients who were >60 days post HSCT were stratified by age and steroid use, and randomized to receive either 1 (n=33) or 2 (n=32) influenza vaccinations separated by one month. Blood samples were obtained pre-vaccination, 4 weeks and 8 weeks after the first vaccine. Vaccine specific B and T cell responses were assessed using hemagglutination inhibition (HAI) and IFN-g ELISPOT, respectively. Of the 65 patients, 73% (n=48) were >18 yrs old, 40% (n=26) received non-myeloablative conditioning and 35% (n=23) were umbilical cord blood (UCB) transplant recipients. HAI responses to the 2010/2011 vaccine components (H3N2, H1N1 and B/Victoria) were significantly greater for patients vaccinated >1 year post transplant (p<=0.005 for all 3 strains) compared to those vaccinated at earlier time points. Testing of T cell specific responses (IFN-g ELISPOT at week 8) showed 29/65 (45%) patients had IFN-g vaccine specific responses (defined as >5x increase in the number of spots over baseline). Recipients of 2 vaccines did not show a significant improvement in either HAI or in IFN-g ELISPOT responses. The HAI results were similar to the T cell specific responses in that patients >1 year after HSCT were more likely to develop positive responses compared to those vaccinated <1 yr (p=0.03). UCB recipients were less likely to have an influenza specific T cell response (p=<0.001). Flow cytometry was performed to determine whether the numbers of pre-vaccination naïve, effector memory or central memory T and or similar B cell populations were associated with responses. There was a positive correlation between the total number of CD19+ cells prior to vaccination and seroconversion (p=0.01) and an inverse correlation for IFN-g responses (p=0.05). No correlation with CD4+ subsets were found for either seroconversion or IFN-g positivity. In multivariate analysis for HAI responses, time from transplant to vaccination, and greater numbers of prevaccination CD19+ cells were significantly associated with responses (p<0.001 and p=0.01 respectively). Multivariate analysis for vaccine specific ELISPOT responses demonstrated significance for stem cell source (PB/BM > UCB, p=0.005) and CD19+ unswitched memory cells (p=0.008). Our study illustrates that time from transplantation was the strongest predictor of vaccine associated responses, and that vaccine specific T cell responses can be elicited prior to antibody responses. Furthermore, UCB recipients had significantly fewer IFN-g vaccine specific responses. Surprisingly steroid use did not negatively impact vaccine responses. In summary an additional influenza vaccine dose, separated by 1 month, did not increase vaccine responses. Disclosures: Blazar: Tarix Pharmaceuticals: Research Funding; Boehringer Ingelheim: Research Funding; Acetylon Pharmaceuticals, Inc.: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; University of Minnesota/University of Pennsylvania: Licensing Agreement, Licensing Agreement Other; Athelos-NeoStem, Inc.: Consultancy.

scholarly journals Cellular and humoral responses to SARS-CoV-2 vaccination in immunosuppressed patients

2021 ◽  
Author(s):  
Dinesh Mohanraj ◽  
Samuel Baldwin ◽  
Satbeer Singh ◽  
Alun Gordon ◽  
Alison Whitelegg
Keyword(s):  
T Cell ◽  
T Cell Responses ◽  
Effector Memory ◽  
Immunological Responses ◽  
Vaccine Responses ◽  
Cell Responses ◽  
Immunosuppressed Patients ◽  
Vaccine Immunogenicity ◽  
Humoral Responses ◽  
The Impact

ABSTRACTObjectiveSARS-CoV-2 vaccinations have demonstrated vaccine immunogenicity in healthy volunteers, however, efficacy in immunosuppressed patients is less well characterised. Subsequently, there is an urgent need to address the impact of immunosuppression on vaccine immunogenicity.MethodsSerological, T-cell ELISpot, cytokines and immunophenotyping investigations were used to assess vaccine responses (either BNT162b2 mRNA or ChAdOx1 nCoV-19) in double-vaccinated patients receiving immunosuppression for renal transplants or haematological malignancies (n=13). Immunological responses in immunosuppressed patients (VACC-IS) were compared to immunocompetent vaccinated (VACC-IC, n=12), unvaccinated (UNVACC, n=11) and infection-naïve unvaccinated (HC, n=3) cohorts. All participants, except HC, had prior COVID-19 infection.ResultsT-cell responses were identical between VACC-IS and VACC-IC (92%) to spike-peptide (S) stimulation. UNVACC had the highest T-cell non-responders (n=3), whereas VACC-IC and VACC-IS both had one T-cell non-responder. No significant differences in humoral responses were observed between VACC-IC and VACC-IS, with 92% (12/13) of VACC-IS patients demonstrating seropositivity. One VACC-IS failed to seroconvert, however had detectable T-cell responses. All VACC-IC participants were seropositive for anti-spike antibodies. Furthermore, both VACC-IS and VACC-IC participants elicited strong Th1 cytokine response with immunodominance towards S-peptide. Differences in T-cell immunophenotyping were seen between VACC-IS and VACC-IC, with lower CD8+ activation and T-effector memory phenotype observed in VACC-IS.ConclusionSARS-CoV-2 vaccines are immunogenic in patients receiving immunosuppressive therapy, with responses comparable to vaccinated immunocompetent participants. Lower humoral responses were seen in patients treated with B-cell depleting therapeutics, but with preserved T-cell responses. We suggest further work to correlate both protective immunity and longevity of these responses in both healthy and immunosuppressed patients.

scholarly journals Two doses of SARS-CoV-2 vaccination induce more robust immune responses to emerging SARS-CoV-2 variants of concern than does natural infection.

2021 ◽  
Author(s):  
Donal T. Skelly ◽  
Adam C. Harding ◽  
Javier Gilbert-Jaramillo ◽  
Michael L. Knight ◽  
Stephanie Longet ◽  
...  
Keyword(s):  
T Cell ◽  
Immune Responses ◽  
Natural Infection ◽  
Vaccine Dose ◽  
T Cell Responses ◽  
T Cell Response ◽  
Potential Threat ◽  
Cell Responses ◽  
Reference Isolate ◽  
The Impact

Abstract Both natural infection with SARS-CoV-2 and immunization with vaccines induce protective immunity. However, the extent to which such immune responses protect against emerging variants is of increasing importance. Such variants of concern (VOC) include isolates of lineage B.1.1.7, first identified in the UK, and B.1.351, first identified in South Africa. Our data confirm that VOC, particularly those with substitutions at residues 484 and 417, escape neutralization by antibodies directed to the ACE2-binding Class 1 and the adjacent Class 2 epitopes but are susceptible to neutralization by the generally less potent antibodies directed to Class 3 and 4 epitopes on the flanks of the receptor-binding domain. To address the potential threat posed by VOC, we sampled a SARS-CoV-2 uninfected UK cohort recently vaccinated with BNT162b2 (Pfizer-BioNTech, two doses delivered 18-28 days apart), alongside a cohort sampled in the early convalescent stages after natural infection in the first wave of the pandemic in Spring 2020. We tested antibody and T cell responses against a reference isolate of the original circulating lineage, B, and the impact of sequence variation in the B.1.1.7 and B.1.351 VOC. Neutralization of the VOC compared to B isolate was reduced, and this was most evident for the B.1.351 isolate. This reduction in antibody neutralization was less marked in post-boost vaccine-induced responses compared to naturally induced immune responses and could be largely explained by the potency of the homotypic antibody response. After a single vaccination, which induced only modestly neutralizing homotypic antibody titres, neutralization against the VOC was completely abrogated in the majority of vaccinees. Importantly, high magnitude T cell responses were generated after two vaccine doses, with the majority of the T cell response directed against epitopes that are conserved between the prototype isolate B and the VOC. These data indicate that VOC may evade protective neutralizing responses induced by prior infection, and to a lesser extent by immunization, particularly after a single vaccine dose, but the impact of the VOC on T cell responses appears less marked. The results emphasize the need to generate high potency immune responses through vaccination in order to provide protection against these and other emergent variants.

scholarly journals Omicron-specific cytotoxic T-cell responses are boosted following a third dose of mRNA COVID-19 vaccine in anti-CD20-treated multiple sclerosis patients

2021 ◽  
Author(s):  
Natacha Madelon ◽  
Nelli Heikkila ◽  
Irene Sabater Royo ◽  
Paola Fontannaz ◽  
Gautier Breville ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Vaccine Dose ◽  
T Cell Responses ◽  
Antibody Responses ◽  
Cytotoxic T Cell ◽  
Cell Responses ◽  
The Third ◽  
Before And After ◽  
Anti Cd20

Importance: The SARS-CoV-2 variant Omicron escapes neutralizing antibody responses elicited after COVID-19 vaccination, while T-cell responses might be better conserved. It is crucial to assess how a third dose of vaccination modifies these responses, particularly for immunocompromised patients with readily impaired antibody responses. Objective: To determine T-cell responses to the Spike (S)-protein of Omicron in anti-CD20 treated patients before and after their third mRNA COVID-19 vaccination Design: Prospective observational monocentric study Setting: Conducted since March 2021 at the University Hospital Geneva Participants: Twenty adults with multiple sclerosis on anti-CD20 treatment (ocrelizumab) who received their third dose of mRNA COVID-19 vaccine 6 to 7 months after their second vaccination. Intervention: Blood sampling before and one month after the third vaccine dose Main outcomes and measures: Quantification of CD4 and CD8 (cytotoxic) T cells specific for SARS-CoV-2 S-protein of vaccine strain, Delta and Omicron variants , using activation marker induced assay (AIM) and comparing frequencies before and after the third vaccine dose. Results: S-specific CD4 and CD8 T-cell memory against all variants was maintained in around half of the patients six months after their second vaccination, albeit at lower frequencies against Delta and Omicron variants. A third dose enhanced the number of responders to all variants and significantly increased CD8 T-cell responses. The frequencies of T cells specific to Omicron and Delta remained lower than those specific to the vaccine strain after the boost. Conclusion and relevance: Vaccinated MS patients on anti-CD20 treatment show robust T-cell responses that recognize S from the circulating Delta and Omicron variants. Response rates increased after the third dose, demonstrating that a booster dose might improve cytotoxic T-cell mediated protection against severe disease in patients with low humoral response. The clinical relevance of the reduced frequencies of T cells specific to Omicron will need to be monitored in the future.

scholarly journals Cellular and Humoral Responses to SARS-CoV-2 Vaccination in Immunosuppressed Patients

2022 ◽  
Author(s):  
Dinesh Mohanraj ◽  
Samuel Baldwin ◽  
Satbeer Singh ◽  
Alun Gordon ◽  
Alison Whitelegg
Keyword(s):  
T Cell ◽  
T Cell Responses ◽  
Effector Memory ◽  
Immunological Responses ◽  
Vaccine Responses ◽  
Cell Responses ◽  
Immunosuppressed Patients ◽  
Vaccine Immunogenicity ◽  
Humoral Responses ◽  
The Impact

Abstract Objective: SARS-CoV-2 vaccinations have demonstrated vaccine-immunogenicity in healthy volunteers, however, efficacy in immunosuppressed patients is less well characterised. There is an urgent need to address the impact of immunosuppression on vaccine immunogenicity. Methods: Serological, T-cell ELISpot, cytokines and immunophenotyping assays were used to assess vaccine responses (either BNT162b2 mRNA or ChAdOx1 nCoV-19) in double-vaccinated patients receiving immunosuppression for renal transplants or haematological malignancies (n=13). Immunological responses in immunosuppressed patients (VACC-IS) were compared to immunocompetent vaccinated (VACC-IC, n=12), unvaccinated (UNVACC, n=11) and infection-naïve unvaccinated (HC, n=3) cohorts. All participants, except HC, had prior COVID-19 infection. Results: T-cell responses were identical between VACC-IS and VACC-IC (92%) to spike-peptide (S) stimulation. UNVACC had the highest T-cell non-responders (n=3), whereas VACC-IC and VACC-IS both had one T-cell non-responder. No significant differences in humoral responses were observed between VACC-IC and VACC-IS, with 92% (12/13) of VACC-IS patients demonstrating seropositivity. One VACC-IS failed to seroconvert, however had detectable T-cell responses. All VACC-IC participants were seropositive for anti-spike antibodies. VACC-IS and VACC-IC participants elicited strong Th1 cytokine response with immunodominance towards S-peptide. Differences in T-cell immunophenotyping were seen between VACC-IS and VACC-IC, with lower CD8+ activation and T-effector memory phenotype observed in VACC-IS. Conclusion: SARS-CoV-2 vaccines are immunogenic in patients receiving immunosuppressive therapy, with responses comparable to vaccinated immunocompetent participants. Lower humoral responses were seen in patients treated with B-cell depleting therapeutics, but with preserved T-cell responses. We suggest further work to correlate both protective immunity and longevity of these responses in both healthy and immunosuppressed patients.

scholarly journals Batf3-Dependent Dendritic Cells Promote Optimal CD8 T Cell Responses against Respiratory Poxvirus Infection

2018 ◽  
Vol 92 (16) ◽  
Author(s):  
Pritesh Desai ◽  
Vikas Tahiliani ◽  
Georges Abboud ◽  
Jessica Stanfield ◽  
Shahram Salek-Ardakani
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Vaccinia Virus ◽  
Respiratory Infection ◽  
Host Resistance ◽  
T Cell Responses ◽  
Cell Responses ◽  
Ifn Γ ◽  
The Impact

ABSTRACTRespiratory infection with vaccinia virus (VacV) elicits robust CD8+T cell responses that play an important role in host resistance. In the lung, VacV encounters multiple tissue-resident antigen-presenting cell (APC) populations, but which cell plays a dominant role in priming of virus-specific CD8+effector T cell responses remains poorly defined. We used Batf3−/−mice to investigate the impact of CD103+and CD8α+dendritic cell (DC) deficiency on anti-VacV CD8+T cell responses. We found that Batf3−/−mice were more susceptible to VacV infection, exhibiting profound weight loss, which correlated with impaired accumulation of gamma interferon (IFN-γ)-producing CD8+T cells in the lungs. This was largely due to defective priming since early in the response, antigen-specific CD8+T cells in the draining lymph nodes of Batf3−/−mice expressed significantly reduced levels of Ki67, CD25, and T-bet. These results underscore a specific role for Batf3-dependent DCs in regulating priming and expansion of effector CD8+T cells necessary for host resistance against acute respiratory VacV infection.IMPORTANCEDuring respiratory infection with vaccinia virus (VacV), a member ofPoxviridaefamily, CD8+T cells play important role in resolving the primary infection. Effector CD8+T cells clear the virus by accumulating in the infected lungs in large numbers and secreting molecules such as IFN-γ that kill virally infected cells. However, precise cell types that regulate the generation of effector CD8+T cells in the lungs are not well defined. Dendritic cells (DCs) are a heterogeneous population of immune cells that are recognized as key initiators and regulators of T-cell-mediated immunity. In this study, we reveal that a specific subset of DCs that are dependent on the transcription factor Batf3 for their development regulate the magnitude of CD8+T cell effector responses in the lungs, thereby providing protection during pulmonary VacV infection.

scholarly journals Fitness-Balanced Escape Determines Resolution of Dynamic Founder Virus Escape Processes in HIV-1 Infection

2015 ◽  
Vol 89 (20) ◽  
pp. 10303-10318 ◽  
Author(s):  
Justine E. Sunshine ◽  
Brendan B. Larsen ◽  
Brandon Maust ◽  
Ellie Casey ◽  
Wenje Deng ◽  
...  
Keyword(s):  
T Cell ◽  
Viral Evolution ◽  
T Cell Responses ◽  
Fitness Cost ◽  
Viral Population ◽  
Cell Responses ◽  
Founder Virus ◽  
Ctl Escape ◽  
The Impact ◽  
Hiv 1

ABSTRACTTo understand the interplay between host cytotoxic T-lymphocyte (CTL) responses and the mechanisms by which HIV-1 evades them, we studied viral evolutionary patterns associated with host CTL responses in six linked transmission pairs. HIV-1 sequences corresponding to full-length p17 and p24gagwere generated by 454 pyrosequencing for all pairs near the time of transmission, and seroconverting partners were followed for a median of 847 days postinfection. T-cell responses were screened by gamma interferon/interleukin-2 (IFN-γ/IL-2) FluoroSpot using autologous peptide sets reflecting any Gag variant present in at least 5% of sequence reads in the individual's viral population. While we found little evidence for the occurrence of CTL reversions, CTL escape processes were found to be highly dynamic, with multiple epitope variants emerging simultaneously. We found a correlation between epitope entropy and the number of epitope variants per response (r= 0.43;P= 0.05). In cases in which multiple escape mutations developed within a targeted epitope, a variant with no fitness cost became fixed in the viral population. When multiple mutations within an epitope achieved fitness-balanced escape, these escape mutants were each maintained in the viral population. Additional mutations found to confer escape but undetected in viral populations incurred high fitness costs, suggesting that functional constraints limit the available sites tolerable to escape mutations. These results further our understanding of the impact of CTL escape and reversion from the founder virus in HIV infection and contribute to the identification of immunogenic Gag regions most vulnerable to a targeted T-cell attack.IMPORTANCERapid diversification of the viral population is a hallmark of HIV-1 infection, and understanding the selective forces driving the emergence of viral variants can provide critical insight into the interplay between host immune responses and viral evolution. We used deep sequencing to comprehensively follow viral evolution over time in six linked HIV transmission pairs. We then mapped T-cell responses to explore if mutations arose due to adaption to the host and found that escape processes were often highly dynamic, with multiple mutations arising within targeted epitopes. When we explored the impact of these mutations on replicative capacity, we found that dynamic escape processes only resolve with the selection of mutations that conferred escape with no fitness cost to the virus. These results provide further understanding of the complicated viral-host interactions that occur during early HIV-1 infection and may help inform the design of future vaccine immunogens.

scholarly journals Regulation of T Cell Responses by Ionic Salt Signals

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2365
Author(s):  
Christina E. Zielinski
Keyword(s):  
T Cells ◽  
T Cell ◽  
Sodium Chloride ◽  
T Cell Responses ◽  
T Helper Cell ◽  
Helper Cell ◽  
T Helper ◽  
Tissue Microenvironment ◽  
Cell Responses ◽  
The Impact

T helper cell responses are tailored to their respective antigens and adapted to their specific tissue microenvironment. While a great proportion of T cells acquire a resident identity, a significant proportion of T cells continue circulating, thus encountering changing microenvironmental signals during immune surveillance. One signal, which has previously been largely overlooked, is sodium chloride. It has been proposed to have potent effects on T cell responses in the context of autoimmune, allergic and infectious tissue inflammation in mouse models and humans. Sodium chloride is stringently regulated in the blood by the kidneys but displays differential deposition patterns in peripheral tissues. Sodium chloride accumulation might furthermore be regulated by dietary intake and thus by intentional behavior. Together, these results make sodium chloride an interesting but still controversial signal for immune modulation. Its downstream cellular activities represent a potential therapeutic target given its effects on T cell cytokine production. In this review article, we provide an overview and critical evaluation of the impact of this ionic signal on T helper cell polarization and T helper cell effector functions. In addition, the impact of sodium chloride from the tissue microenvironment is assessed for human health and disease and for its therapeutic potential.

scholarly journals Baseline Levels of Influenza-Specific B Cells and T Cell Responses Modulate Human Immune Responses to Swine Variant Influenza A/H3N2 Vaccine

Vaccines ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 126
Author(s):  
Lilin Lai ◽  
Nadine Rouphael ◽  
Yongxian Xu ◽  
Amy C. Sherman ◽  
Srilatha Edupuganti ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Influenza A ◽  
Vaccine Dose ◽  
T Cell Responses ◽  
Post Vaccination ◽  
Cell Responses ◽  
Cellular Immune Responses ◽  
Cellular Immune

The cellular immune responses elicited by an investigational vaccine against an emergent variant of influenza (H3N2v) are not fully understood. Twenty-five subjects, enrolled in an investigational influenza A/H3N2v vaccine study, who received two doses of vaccine 21 days apart, were included in a sub-study of cellular immune responses. H3N2v-specific plasmablasts were determined by ELISpot 8 days after each vaccine dose and H3N2v specific CD4+ T cells were quantified by intracellular cytokine and CD154 (CD40 ligand) staining before vaccination, 8 and 21 days after each vaccine dose. Results: 95% (19/20) and 96% (24/25) subjects had pre-existing H3N2v specific memory B, and T cell responses, respectively. Plasmablast responses at Day 8 after the first vaccine administration were detected against contemporary H3N2 strains and correlated with hemagglutination inhibition HAI (IgG: p = 0.018; IgA: p < 0.001) and Neut (IgG: p = 0.038; IgA: p = 0.021) titers and with memory B cell frequency at baseline (IgA: r = 0.76, p < 0.001; IgG: r = 0.74, p = 0.0001). The CD4+ T cells at Days 8 and 21 expanded after prime vaccination and this expansion correlated strongly with early post-vaccination HAI and Neut titers (p ≤ 0.002). In an adult population, the rapid serological response observed after initial H3N2v vaccination correlates with post-vaccination plasmablasts and CD4+ T cell responses.

scholarly journals 2729. mRNA Vaccines Encoding Conserved Influenza Antigens Induce Robust and Durable Immunity in Rhesus Macaques

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S961-S961
Author(s):  
Jessica Flynn ◽  
Kara Cox ◽  
Sinoeun Touch ◽  
Yangsi Ou ◽  
Teresa Weber ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cell ◽  
Rhesus Macaques ◽  
Vaccine Dose ◽  
T Cell Responses ◽  
Immune Recognition ◽  
Serum Antibodies ◽  
Ifn Gamma ◽  
Cell Responses ◽  
Lipid Nanoparticle

Abstract Background In response to immune pressure, influenza virus evolves, producing drifted variants capable of escaping immune recognition. One strategy for inducing a broad-spectrum immune response that can recognize multiple antigenically diverse strains is to target conserved proteins or protein domains. To that end, we assessed the immunogenicity of mRNA vaccines encoding the stem domain of hemagglutinin (HA) or nucleoprotein (NP) in nonhuman primates (NHPs). Methods Rhesus macaques were immunized three times intramuscularly, at 28 day intervals, with lipid nanoparticle-encapsulated mRNA encoding either HA stem (Yassine et al, 2015) or NP. Serum and PBMCs were collected up to 14 or 24 weeks, respectively, after the last vaccination. The magnitude and durability of humoral and cell-mediated immunity were evaluated. ELISA, competition ELISA, an in vitro antibody-dependent cell-mediated cytotoxicity (ADCC) reporter bioassay, and microneutralization assays were used to characterize serum immune responses. Intracellular cytokine staining (IFN-gamma and IL-2) was used to assess antigen-specific T-cell responses. Results HA stem-immunized NHPs developed a robust anti-stem binding titer after a single vaccine dose, and after two doses, serum antibodies recognized several antigenically distinct Group 1 HA proteins. This broad antibody response persisted for at least 14 weeks post-dose 3 (PD3). Serum antibodies showed ADCC activity and competed with a well-characterized broadly neutralizing antibody, CR9114, for binding to HA stem; however, the polyclonal serum had only minimal activity against a panel of H1N1 viruses in a microneutralization assay. HA-specific CD4+ T-cell responses were detectable PD3. A robust antibody binding response was also detected in NP-vaccinated NHPs, and titers remained high for at least 14 weeks PD3. Additionally, these animals developed robust NP-specific T-cell responses that persisted for at least 24 weeks PD3. On average, 0.5% of CD4+ and 4% of CD8+ T cells produced IFN-gamma in response to NP peptide stimulation at the peak of the response, 2 weeks after the last vaccine dose was administered. Conclusion Lipid nanoparticle-encapsulated mRNA vaccines encoding conserved influenza antigens induce a robust and durable immune response in NHPs. Disclosures All authors: No reported disclosures.

Sign in / Sign up

Export Citation Format

Share Document