scholarly journals Immune responses to a single dose of the AZD1222/Covishield vaccine at 16 weeks in individuals in Sri Lanka

2021 ◽  
Author(s):  
Chandima Jeewandara ◽  
Dinuka Guruge ◽  
Pradeep Pushpakumara ◽  
Achala Kamaladasa ◽  
Inoka Aberathna ◽  
...  
Keyword(s):  
Single Dose ◽  
T Cell ◽  
B Cell ◽  
High Frequency ◽  
Ex Vivo ◽  
P Value ◽  
Receptor Blocking ◽  
Specific Antibodies ◽  
Cell Responses ◽  
Blocking Antibodies

Introduction: Due to limited access to vaccines, many countries have only administered a single dose of the AZD1222, while the dosage intervals have increased ≥ weeks. We sought to investigate the immunogenicity of a single dose of vaccine at ≥ 16 weeks. Methods: SARS-CoV-2 specific antibodies in 553 individuals and antibodies to the receptor binding domain (RBD) of the Wuhan virus (WT) and the variants of concern (VOCs), ACE2 receptor blocking antibodies, ex vivo and cultured IFNγ T cell responses and B cell ELISpot responses were investigated in a sub-cohort. Results: The seropositivity rates in those >70 years of age (93.7%) was not significantly different compared to other age groups (97.7 to 98.2, Pearson Chi-Square = 7.8, p-value = 0.05). The antibody titres (antibody index) significantly declined (p<0.0001) with increase in age. 18/69 (26.1%) of individuals did not have ACE2 receptor blocking antibodies, while responses to the RBD of WT (p=0.03), B.1.1.7 (p=0.04) and B.1.617.2 (p=0.02) were significantly lower in those who were >60 years. Ex vivo IFN γ T cell ELISpot responses were seen in 10/66 (15.1%), while only a few expressed CD107a. However, >85% had a high frequency of cultured IFNγ T cell ELISpot responses and B cell ELISpots. Conclusion: Virus specific antibodies were maintained at ≥ 16 weeks after receiving a single dose of AZD1222, although levels were lower to VOCs, especially in older individuals. A single dose induced a high frequency of memory T and B cell responses.

scholarly journals Immune responses following the first dose of the Sputnik V (Gam-COVID-Vac)

2021 ◽  
Author(s):  
Chandima Jeewandara ◽  
Harsha Fernando ◽  
Pradeep Pushpakumara ◽  
Shyrar Tanussiya ◽  
Achala Kamaladasa ◽  
...  
Keyword(s):  
Single Dose ◽  
Immune Responses ◽  
High Frequency ◽  
Ex Vivo ◽  
Natural Infection ◽  
Receptor Binding Domain ◽  
Cell Responses ◽  
Blocking Antibodies ◽  
With Memory ◽  
Dose Vaccine

Abstract As the first dose of Gam-COVID-Vac, is currently used as a single dose vaccine in some countries, we investigated the immunogenicity of this at 4 weeks (327 naïve individuals). 88.7% seroconverted, with significantly lower seroconversion rates in those over 60 years (p = 0.004) and significantly lower than previously seen with AZD1222 (p = 0.018). 82.6% developed ACE2 receptor blocking antibodies, although levels were significantly lower than following natural infection (p = 0.0009) and a single dose of AZD1222 (p < 0.0001). Similar titres of antibodies were observed to the receptor binding domain of WT, B.1.1.7 and B.1.617.2 compared to AZD1222, while the levels for B.1.351 were significantly higher (p = 0.006) for Gam-COVID-Vac. 30% developed ex vivo IFNγ ELISpot responses (significantly lower than AZD1222), and high frequency of CD107a expressing T cells along with memory B cell responses. Although single dose of Gam-COVID-Vac was highly immunogenic, administration of a second dose is likely to be beneficial.

scholarly journals Antibody and T cell responses to Sinopharm/BBIBP-CorV in naive and previously infected individuals in Sri Lanka

2021 ◽  
Author(s):  
Chandima Jeewandara ◽  
Inoka Sepali Aberathna ◽  
Pradeep Dharshana Pushpakumara ◽  
Achala Kamaladasa ◽  
Dinuka Guruge ◽  
...  
Keyword(s):  
T Cell ◽  
Sri Lanka ◽  
Ex Vivo ◽  
Natural Infection ◽  
T Cell Responses ◽  
Antibody Responses ◽  
Receptor Blocking ◽  
Cell Responses ◽  
Antibody Titres ◽  
Blocking Antibodies

Background: As there are limited data of the immunogenicity of the Sinopharm/BBIBP-CorV in different populations, antibody responses against different SARS-CoV-2 variants of concern and T cell responses, we investigated the immunogenicity of the vaccine, in individuals in Sri Lanka. Methods: SARS-CoV-2-specific antibodies were measured in 282 individuals who were seronegative at baseline, and ACE2 receptor blocking antibodies, antibodies to the receptor binding domain (RBD) of the wild type (WT), B.1.1.7, B.1.351 and B.1.617.2, ex vivo and cultured IFNγ ELISpot assays, intracellular cytokine secretion assays and B cell ELISpot assays were carried out in a sub cohort of the vaccinees at 4 weeks and at 6 weeks (2 weeks after the second dose). Results: 95% of the vaccinees seroconverted, although the seroconversion rates were significantly lower (p<0.001) in individuals >60 years (93.3%) compared to those who were 20 to 39 years (98.9%). 81.25% had ACE2 receptor blocking antibodies at 6 weeks, and there was no difference in these antibody titres in vaccine sera compared to convalescent sera (p=0.44). Vaccinees had significantly less (p<0.0001) antibodies to the RBD of WT and B.1.1.7, although there was no difference in antibodies to the RBD of B.1.351 and B.1.617.2 compared to convalescent sera. 27.7% of 46.4% of vaccinees had ex vivo IFNγ and cultured ELISpot responses respectively, and IFNγ and CD107a responses were detected by flow cytometry. Conclusions: Sinopharm/BBIBP-CorV appeared to induce high seroconversion rates and induce a similar level of antibody responses against ACE2 receptor, B.1.617.2 and B.1.351 as seen following natural infection.

scholarly journals Immune responses following the first dose of the Sputnik V (Gam-COVID-Vac)

2021 ◽  
Author(s):  
Gathsaurie Malavige ◽  
Chandima Jeewandara ◽  
Harsha Fernando ◽  
Pradeep Darshana Pushpakumara ◽  
Shyrar Tanussiya ◽  
...  
Keyword(s):  
Single Dose ◽  
Immune Responses ◽  
High Frequency ◽  
Ex Vivo ◽  
Natural Infection ◽  
Receptor Binding Domain ◽  
Cell Responses ◽  
Blocking Antibodies ◽  
With Memory ◽  
Dose Vaccine

Abstract As the first dose of Gam-COVID-Vac, is currently used as a single dose vaccine in some countries, we investigated the immunogenicity of this at 4 weeks (327 naïve individuals). 88.7% seroconverted, with significantly lower seroconversion rates in those over 60 years (p = 0.004) and significantly lower than previously seen with AZD1222 (p = 0.018). 82.6% developed ACE2 receptor blocking antibodies, although levels were significantly lower than following natural infection (p = 0.0009) and a single dose of AZD1222 (p < 0.0001). Similar titres of antibodies were observed to the receptor binding domain of WT, B.1.1.7 and B.1.617.2 compared to AZD1222, while the levels for B.1.351 were significantly higher (p = 0.006) for Gam-COVID-Vac. 30% developed ex vivo IFNγ ELISpot responses (significantly lower than AZD1222), and high frequency of CD107a expressing T cells along with memory B cell responses. Although single dose of Gam-COVID-Vac was highly immunogenic, administration of a second dose is likely to be beneficial.

scholarly journals Antibody and T-cell responses to a single dose of the AZD1222/Covishield vaccine in previously SARS-CoV-2 infected and naive health care workers in Sri Lanka

2021 ◽  
Author(s):  
Chandima Jeewandara ◽  
Achala Kamaladasa ◽  
Pradeep D Pushpakumara ◽  
Deshni Jayathilaka ◽  
Inoka Sepali ◽  
...  
Keyword(s):  
Health Care ◽  
Single Dose ◽  
T Cell ◽  
Health Care Workers ◽  
Ex Vivo ◽  
T Cell Responses ◽  
Wild Type Virus ◽  
Cell Responses ◽  
Care Workers ◽  
Blocking Antibodies

Background: In order to determine the immunogenicity of a single dose of the AZD1222/Covishield vaccine in a real-world situation, we assessed the immunogenicity, in a large cohort of health care workers in Sri Lanka. Methods: SARS-CoV-2 antibodies was carried out in 607 naive and 26 previously infected health care workers (HCWs) 28 to 32 days following a single dose of the vaccine. Haemagglutination test (HAT) for antibodies to the receptor binding domain (RBD) of the wild type virus, B.1.1.7, B.1.351 and the surrogate neutralization assay (sVNT) was carried out in 69 naive and 26 previously infected individuals. Spike protein (pools S1 and S2) specific T cell responses were measured by ex vivo ELISpot IFNg; assays in 76 individuals. Results: 92.9% of previously naive HCWs seroconverted to a single dose of the vaccine, irrespective of age and gender; and ACE2 blocking antibodies were detected in 67/69 (97.1%) previously naive vaccine recipients. Although high levels of antibodies were found to the RBD of the wild type virus, the titres for B.1.1.7 and B.1.351 were lower in previously naive HCWs. Ex vivo T cell responses were observed to S1 in 63.9% HCWs and S2 in 31.9%. The ACE2 blocking titres measured by the sVNT significantly increased (p<0.0001) from a median of 54.1 to 97.9 % of inhibition, in previously infected HCWs and antibodies to the RBD for the variants B.1.1.7 and B.1.351 also significantly increased. Discussion: a single dose of the AZD1222/Covishield vaccine was shown to be highly immunogenic in previously naive individuals inducing antibody levels greater than following natural infection. In infected individuals, a single dose induced very high levels of ACE2 blocking antibodies and antibodies to RBDs of SARS-CoV-2 variants of concern.

scholarly journals The Tigit/CD226/CD155 Immunomodulatory Axis Is Deregulated in CLL and Contributes to B-Cell Anergy

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3718-3718
Author(s):  
Francesca Arruga ◽  
Andrea Iannello ◽  
Nikolaos Ioannou ◽  
Alberto Maria Todesco ◽  
Marta Coscia ◽  
...  
Keyword(s):  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Board Of Directors ◽  
Research Funding ◽  
Cell Receptor ◽  
Tcr Signaling ◽  
Advisory Committees ◽  
Cell Responses ◽  
Blocking Antibodies

Abstract BACKGROUND. T cell immunoreceptor with Ig and ITIM domains (TIGIT) is an inhibitory receptor expressed on T, NK and NKT cells, sharing structural and mechanistic similarities with PD-1 and CTLA-4. TIGIT competes with CD226, its partner receptor, for the binding to CD155 ligand: signaling triggered upon CD155 binding to CD226 potentiates T cell receptor (TCR) signaling and CD8 + T cell cytotoxicity against tumor cells (positive signaling). On the contrary, concomitant TIGIT expression on the cell surface prevents CD226 activation either by sequestering CD155 or by impeding CD226 homodimerization and phosphorylation (negative signaling). Recently, TIGIT was shown to be expressed on the surface of normal memory B cells, where it could directly act to suppress T cell responses. No data are available on TIGIT or CD226 expression by chronic lymphocytic leukemia (CLL) cells. AIM AND METHODS. Our aim was to investigate expression of the TIGIT and CD226 receptors and of the CD155 ligand in a cohort of clinically and molecularly annotated CLL patient samples. To this end, we designed a multiparametric panel of antibodies for flow cytometry and examined expression of the TIGIT/CD226/CD155 axis in peripheral blood mononuclear cells (PBMC) from our patient cohort. To investigate the impact of TIGIT/CD226 engagement on B cell responses, purified leukemic B cells were activated either through the B cell receptor (BCR) using an αIgM polyclonal antibody or with CpG oligonucleotide and interleukin 15 (IL-15) to induce proliferation. In selected experiments, we added recombinant human (Rh) TIGIT-Fc or CD155-Fc chimeras and αTIGIT or αCD226 blocking antibodies to interfere with this axis. RESULTS. Surface expression of TIGIT, CD226 and CD155 was evaluated in a cohort of 115 CLL samples and compared to age- and sex-matched healthy subjects. Both TIGIT and CD226 were upregulated on leukemic B cells compared to normal B lymphocytes, while CD155 was expressed at lower levels. A similar trend was observed on CD4 + and CD8 + T lymphocytes. High-risk CLLs (unmutated IgV genes, unfavorable cytogenetics and advanced stage) were predominantly TIGIT low and CD226 high, indicating an unbalance towards "positive signaling". Results were confirmed by confocal microscopy analyses on lymph node (LN) biopsies, which showed i) an overall higher TIGIT expression in CLL compared to reactive LNs and ii) among CLL LNs a stronger TIGIT positivity in mutated vs unmutated cases, confirming flow cytometry data. In line with these findings, Richter's syndrome samples and patient-derived xenografts models showed the lowest TIGIT and the highest CD226 levels. We next examined TIGIT axis expression during the follow up of CLL cases who underwent treatment with BTK inhibitor (BTKi). While CD226 levels remained unmodified upon treatment, a sharp decrease in surface TIGIT was detected soon after BTKi initiation. Since TIGIT acts by decreasing TCR signaling to shut down T cell responses, we hypothesized similar functions in B cells. By crosslinking the BCR with an αIgM antibody in a selected cohort of IGHV UM CLL cells, we found that BTK phosphorylation was induced to a lesser extent in TIGIT high compared to TIGIT low samples, suggesting that TIGIT is a marker of CLL cell anergy. Accordingly, interruption of receptors/ligand interactions with RhTIGIT-Fc chimera or with αTIGIT or αCD226 blocking antibodies, modulated BCR signaling capacity. Specifically, in TIGIT high samples, preventing receptor engagement by CD155 increased αIgM-induced BTK phosphorylation; in contrast, in TIGIT low samples, blocking CD155 interaction affected mostly CD226 signaling, thereby depotentiating BCR activation. Similar results were obtained when stimulating CLL cells with CpG/IL-15. Interestingly, we observed a significant upregulation of surface CD226 in CLL cells cultured for 6 days in the presence of CpG/IL-15. CONCLUSIONS. These results show for the first-time expression of TIGIT by CLL cells. Furthermore, they indicate that TIGIT is a marker of CLL cells anergy, whereas activated CLL cells express high levels of CD226. Inhibition of TIGIT binding to CD155 partially restores B cell signaling and activation. Future studies are needed to gain insights on the mechanisms behind its deregulation and to obtain a complete functional characterization of the axis. Disclosures Coscia: AbbVie: Honoraria, Other; Janssen: Honoraria, Other, Research Funding; AstraZeneca: Honoraria; Gilead: Honoraria. Gaidano: Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Astrazeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Beigene: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Allan: Genentech: Consultancy, Research Funding; Epizyme: Consultancy; Pharmacyclics LLC, an AbbVie Company: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria; BeiGene: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Celegene: Research Funding; AstraZeneca Pharmaceuticals LP, Genentech, a member of the Roche Group, Janssen Biotech Inc, TG Therapeutics Inc.: Research Funding; AbbVie Inc, AstraZeneca Pharmaceuticals LP, BeiGene, Janssen Biotech Inc, Pharmacyclics LLC: Consultancy; AbbVie Inc, Ascentage Pharma, Epizyme, Genentech, a member of the Roche Group, Janssen Biotech Inc, Pharmacyclics LLC: Other: Advisory Committee; TG Therapeutics: Research Funding. Furman: Oncotracker: Consultancy; Verastem: Consultancy; Abbvie: Consultancy, Honoraria, Other: Expert testimony; Sunesis: Consultancy; Incyte: Consultancy; Beigene: Consultancy; Acerta/AstraZeneca: Consultancy; Loxo Oncology: Consultancy; Genentech: Consultancy; Morphosys: Consultancy; Pharmacyclics: Consultancy; Sanofi: Consultancy; TG Therapeutics: Consultancy; X4 Pharmaceuticals: Consultancy; Janssen: Consultancy, Honoraria; AstraZeneca: Honoraria. Deaglio: Heidelberg Pharma: Research Funding; Astra Zeneca: Research Funding.

scholarly journals Formation of Immune Complexes with a Tetanus-Derived B Cell Epitope Boosts Human T Cell Responses to Covalently Linked Peptides in an Ex Vivo Blood Loop System

2018 ◽  
Vol 201 (1) ◽  
pp. 87-97 ◽  
Author(s):  
Erika A. K. Fletcher ◽  
Wendy van Maren ◽  
Robert Cordfunke ◽  
Jasper Dinkelaar ◽  
Jeroen D. C. Codee ◽  
...  
Keyword(s):  
T Cell ◽  
B Cell ◽  
Immune Complexes ◽  
Ex Vivo ◽  
Cell Epitope ◽  
T Cell Responses ◽  
Cell Responses ◽  
Human T Cell ◽  
B Cell Epitope ◽  
Covalently Linked

scholarly journals Kinetics of immune responses to the AZD1222/Covishield vaccine with varying dose intervals in Sri Lankan individuals

2021 ◽  
Author(s):  
Chandima Jeewandara ◽  
Inoka Sepali Aberathna ◽  
Laksiri Gomes ◽  
Pradeep Darshana Pushpakumara ◽  
Saubhagya Danasekara ◽  
...  
Keyword(s):  
T Cell ◽  
Immune Responses ◽  
Positive Response ◽  
Ex Vivo ◽  
Age Groups ◽  
T Cell Responses ◽  
Cell Responses ◽  
Antibody Titres ◽  
Blocking Antibodies ◽  
Kinetics Of

AbstractBackgroundTo understand the kinetics of immune responses with different dosing gaps of the AZD1222 vaccine, we compared antibody and T cell responses in two cohorts with two different dosing gaps.MethodsAntibodies to the SARS-CoV-2 virus were assessed in 297 individuals with a dosing gap of 12 weeks, sampled at 12 weeks post second dose (cohort 1) and in 77 individuals with a median dosing gap of 21.4 weeks (cohort 2) sampled 6 weeks post second dose. ACE2 receptor blocking antibodies (ACE2R-Abs), antibodies to the receptor binding domain (RBD) of the virus and variants of concern (VOC) and ex vivo T cell responses were assessed in a sub cohort.ResultsAll individuals (100%) had SARS-CoV-2 specific total antibodies and 94.2% of cohort 1 and 97.1% of cohort 2 had ACE2R-blocking Abs. There was no difference in antibody titres or positivity rates in different age groups in both cohorts. The ACE2R-blocking Abs (p<0.0001) and antibodies to the RBD of the VOCs were significantly higher in cohort 2, compared to cohort 1. 41.2% to 65.8% of different age groups gave a positive response by the haemagglutination assay to the RBD of the ancestral virus and VOCs in cohort 1, while 53.6% to 90% gave a positive response in cohort 2. 17/57 (29.8%) of cohort 1 and 17/29 (58.6%) of cohort 2 had ex vivo IFNγ ELISpot responses above the positive threshold. The ACE2R-blocking antibodies and ex vivo IFNγ ELISpot responses at 12 weeks post-first dose, significantly correlated with levels 12 weeks post second dose (Spearman’s r=0.46, p=0.008) and (Spearman’s r=0.71, p<0.0001) respectively.ConclusionsBoth dosing schedules resulted in high levels of antibody and T cell responses post vaccination, although those with a longer dosing gap had a higher magnitude of responses, possibly as immune responses were measured 6 weeks post second dose compared to 12 weeks post second dose.

scholarly journals Prior SARS-CoV-2 infection rescues B and T cell responses to variants after first vaccine dose

Science ◽  
2021 ◽  
pp. eabh1282
Author(s):  
Catherine J. Reynolds ◽  
Corinna Pade ◽  
Joseph M. Gibbons ◽  
David K. Butler ◽  
Ashley D. Otter ◽  
...  
Keyword(s):  
Single Dose ◽  
T Cell ◽  
B Cell ◽  
Neutralizing Antibodies ◽  
Vaccine Dose ◽  
Human Leukocyte ◽  
T Cell Responses ◽  
Cell Responses ◽  
Cell Immunity ◽  
Prior Infection

SARS-CoV-2 vaccine rollout has coincided with the spread of variants of concern. We investigated if single dose vaccination, with or without prior infection, confers cross protective immunity to variants. We analyzed T and B cell responses after first dose vaccination with the Pfizer/BioNTech mRNA vaccine BNT162b2 in healthcare workers (HCW) followed longitudinally, with or without prior Wuhan-Hu-1 SARS-CoV-2 infection. After one dose, individuals with prior infection showed enhanced T cell immunity, antibody secreting memory B cell response to spike and neutralizing antibodies effective against B.1.1.7 and B.1.351. By comparison, HCW receiving one vaccine dose without prior infection showed reduced immunity against variants. B.1.1.7 and B.1.351 spike mutations resulted in increased, abrogated or unchanged T cell responses depending on human leukocyte antigen (HLA) polymorphisms. Single dose vaccination with BNT162b2 in the context of prior infection with a heterologous variant substantially enhances neutralizing antibody responses against variants.

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