Differences In T-cell Responses Research Articles

Intranasal Prime-Boost with Spike Vectors Generates Antibody and T-Cell Responses at the Site of SARS-CoV-2 Infection.

Long-lived, re-activatable immunity to SARS-CoV-2 and its emerging variants will rely on T cells recognizing conserved regions of viral proteins across strains. Heterologous prime-boost regimens can elicit elevated levels of circulating CD8+ T cells that provide a reservoir of first responders upon viral infection. Although most vaccines are currently delivered intramuscularly (IM), the initial site of infection is the nasal cavity. Here, we tested the hypothesis that a heterologous prime and boost vaccine regimen delivered intranasally (IN) will generate improved immune responses locally at the site of virus infection compared to intramuscular vaccine/booster regimens. In a transgenic human ACE2 murine model, both a Spike-expressing single-cycle adenovirus (SC-Ad) and an IFNß safety-enhanced replication-competent Vesicular Stomatitis Virus (VSV) platform generated anti-Spike antibody and T-cell responses that diminished with age. Although SC-Ad-Spike boosted a prime with VSV-Spike-mIFNß, SC-Ad-Spike alone induced maximal levels of IgG, IgA, and CD8+ T-cell responses. There were significant differences in T-cell responses in spleens compared to lungs, and the intranasal boost was significantly superior to the intramuscular boost in generating sentinel immune effectors at the site of the virus encounter in the lungs. These data show that serious consideration should be given to intranasal boosting with anti-SARS-CoV-2 vaccines.

T-Cell Expression of CXCL13 is Associated with Immunotherapy Response in a Sex-Dependent Manner in Patients with Lung Cancer.

Emerging evidence in preclinical models demonstrates that antitumor immunity is not equivalent between males and females. However, more investigation in patients and across a wider range of cancer types is needed to fully understand sex as a variable in tumor immune responses. We investigated differences in T-cell responses between male and female patients with lung cancer by performing sex-based analysis of single cell transcriptomic datasets. We found that the transcript encoding CXC motif chemokine ligand 13 (CXCL13), which has recently been shown to correlate with T-cell tumor specificity, is expressed at greater levels in T cells isolated from female compared with male patients. Furthermore, increased CXCL13 expression was associated with response to PD1-targeting immunotherapy in female but not male patients. These findings suggest that there are sex-based differences in T-cell function required for response to anti-PD1 therapy in lung cancer that may need to be considered during patient treatment decisions. See related Spotlight by Cruz-Hinojoza and Stromnes, p. 952.

Randomized Phase II Trial of Imiquimod with or without 9-Valent HPV Vaccine versus Observation in Patients with High-grade Pre-neoplastic Cervical Lesions (NCT02864147).

We report the results of a randomized phase II trial of imiquimod, a topical immune-response modulator versus imiquimod plus a 9-valent human papillomavirus (HPV) vaccine (9vHPV) versus clinical surveillance in cervical intraepithelial neoplasia (CIN2/3) patients. We randomly allocated 133 patients with untreated CIN2/3 in equal proportions to a 4-month treatment with self-applied vaginal suppositories containing imiquimod (Arm B) or imiquimod plus a 9vHPV (Arm C) versus clinical surveillance (Arm A). The main outcome was efficacy, defined as histologic regression to CIN1 or less. Secondary outcomes were HPV clearance and tolerability. Exploratory objectives included the comparison of cervical CD4/CD8 T-cell infiltration at baseline, mid-study, and posttreatment by flow cytometry among study arms. Of the 114 evaluable patients 77% and 23% harbored CIN2 and CIN3, respectively. Regression to CIN1 or less was observed in 95% of patients in the imiquimod group (Arm B) compared with 79% in the control/surveillance (Arm A); P = 0.043 and 84% in the imiquimod+9vHPV group (Arm C; P = 0.384 vs. Arm A). Neither of the treatment-arm differences from Arm A reached the prespecified α = 0.025 significance level. No significant differences were noted in the secondary outcome of rate of HPV clearance. The number of tissue-resident memory CD4/CD8 T cells in cytobrush samples demonstrated a >5-fold increase in Arm B/imiquimod when compared with Arm A/surveillance (P < 0.01). In contrast, there was no significant difference in T-cell responses among participants in Arm C when compared with Arm A. Imiquimod treatment was well tolerated. Although imiquimod induced a higher regression to CIN1 or less and significant increases in CD4/CD8 T cells infiltrating the cervix, it did not meet its prespecified statistical outcome for efficacy. A higher regression rate than expected was observed in the surveillance arm of this prospective trial. Future clinical trials with imiquimod targeting CIN3 patients are warranted.

Abstract 4104: Randomized phase II trial of imiquimod with or without 9vHPV vs observation in patients with CIN 2 and 3

Abstract Introduction: We report the results of a randomized phase II trial of imiquimod, a topical immune-response modulator, vs imiquimod plus a 9-valent human papillomavirus vaccine (9vHPV) vs surveillance in cervical intraepithelial neoplasia (CIN) 2 and 3 patients. Methods: We randomly allocated 133 patients with untreated CIN 2/3 in equal proportions to a 4-month treatment with self-applied vaginal suppositories containing imiquimod (arm B) or imiquimod plus 9vHPV (arm C) vs clinical surveillance (arm A). The main outcome was efficacy, defined as histologic regression to CIN 1 or less. Secondary outcomes were HPV clearance and treatment tolerability. Exploratory objectives included the comparison of cervical CD4/CD8 T-cell infiltration at baseline, mid-study, and post-treatment by flow-cytometry. Results: Of the 114 evaluable patients 77% and 23% had CIN2 and CIN3, respectively. Histologic regression to CIN1 or less was observed in 95% of patients in the Arm B: imiquimod group and 84% in the Arm C: imiquimod+9vHPV compared with 79% in Arm A: surveillance (p=0.043 and 0.384, respectively). The difference between either treatment arm compared with control did not reach the prespecified α=0.025. No significant differences were noted in HPV clearance. The number of tissue-resident memory CD4/CD8 T-cells in cytobrush samples demonstrated a &amp;gt;5-fold increase in Arm-B: imiquimod when compared to Arm-A: surveillance (p&amp;lt;0.01). Imiquimod treatment was well tolerated. In contrast, there was no significant difference in T-cell responses among participants in Arm-C compared to Arm-A. Imiquimod treatment was well-tolerated. Conclusions: Although imiquimod induced a higher percentage of regression to CIN1 or less and significant increases in CD4/CD8 T-cells infiltrating the cervix, it did not meet its prespecified statistical outcome for efficacy. A higher regression rate than expected was observed in the surveillance arm of this prospective trial. Future clinical trial with imiquimod targeting CIN3 patients are warranted. Citation Format: Sangini S. Sheth, Ji Eun Oh, Stefania Bellone, Eric R. Siegel, Natalia Buza, Akiko Iwasaki, Alessandro D. Santin. Randomized phase II trial of imiquimod with or without 9vHPV vs observation in patients with CIN 2 and 3 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4104.

303. Tissue-compartment specific differences in T-cell response found in 44 fatal COVID-19 cases

Abstract Background T-cells play an essential role in recognizing and clearing viruses from infected tissues. While the peripheral blood T-cell responses among patients with coronavirus disease 2019 (COVID-19) has been well characterized in the recent literature, little is known about the overall repertoire diversity of T-cell responses and SARS-CoV-2-specific T-cell breadth and depth across tissues in patients with severe COVID-19. To fill this knowledge gap, we evaluated the T-cell immune repertoires using bulk sequencing of multiple tissue samples from a cohort of fatal COVID-19 cases. Methods Lungs, thoracic lymph nodes and spleens were collected at autopsy from a cohort of 44 patients who died with or from COVID-19. DNA was isolated from paraffin embedded tissues fixed with an ethanol buffer and from peripheral blood mononuclear cells (PBMCs) collected perimortem. T-cell receptor beta (TCRb) sequencing was performed using the Adaptive ImmunoSeq platform and the SARS-CoV-2-specific T-cell response was quantified by exact matching of the TCRb sequences with those reported in the ImmuneCODE and VDJdb databases. Results Significantly lower T-cell clonality and higher numbers of unique T-cell rearrangements were observed in lymph nodes compared to the lung tissues and PBMCs across all patients, indicating higher T-cell diversity in the lymph nodes. Clonal expansion was greatest in the PBMCs and least in the lymph node tissues. Pearson correlations between age and SARS-CoV-2 specific T-cell depth, which were controlled for gender and the number of days between onset and death, varied significantly across tissue compartments in both magnitude and directionality. We observed a strong positive correlation (0.35, p&amp;lt; 0.05) between the SARS-CoV-2 specific T-cell depth and older age in the lymph node samples, that was in contrast with an opposite trend in the PBMCs (-0.52, p&amp;lt; 0.001).Figure 1:Lymph node tissues had increased T-cell counts (clone_count: color scale) and increased unique T-cells (clonotype_count: circle size) when compared to PBMCs and lung tissues.Figure 2.PBMC and lung samples have increased clonality (sample_clonality: circle size) and max frequency for the immunodominant clonotype (max_frequency: color scale) when compared to lymph node tissues. Conclusion The higher depth of SARS-CoV-2 specific T-cells within lymph nodes of older patients that was not observed within circulating PBMCs suggest a deficit of translocation of virus-specific T cells from the site of antigen presentation to circulation and the site of infection, with implications for the increased severity of disease observed in older patients with COVID-19. Disclosures All Authors: No reported disclosures

Dynamic Responses of Circulating T Cells After Stereotactic Body Radiation Therapy for Bone Metastasis in Patients With Breast Cancer

Preclinical studies have shown that radiation therapy modulates antitumor immune responses. However, circulating T-cell responses after radiation therapy in patients with cancer have been poorly characterized. This study aims to explore the changes in circulating T cells after stereotactic body radiation therapy (SBRT). Peripheral blood samples of 30 patients with breast cancer who underwent SBRT for bone metastasis were analyzed using multicolor flow cytometry. Phenotypes of PD-1+ CD8+ T cells and regulatory T (TREG) cells were examined. Additionally, plasma protein levels were analyzed using a bead-based immunoassay. Circulating PD-1+ CD8+ T cells, which are enriched for tumor-specific clonotypes, were activated at 1 week after SBRT. However, circulating TREG cells were also activated after SBRT; this pattern was also evident among effector Foxp3hiCD45RA- TREG cells. We observed no difference in T-cell responses according to the fraction size and number. Notably, activation of TREG cells was more prominent in patients who experienced greater activation of PD-1+ CD8+ T cells. Plasma level changes in TGF-β1, soluble CTLA-4, and soluble 4-1BB at 1 week after SBRT were associated with PD-1+ CD8+ T-cell responses. Activation of TREG cells at 1 week after SBRT was associated with worse progression-free survival. Clinical factors including molecular subtype were not associated with the T-cell responses. SBRT induced activation of both potentially tumor-specific CD8+ T cells and TREG cells, which were tightly associated with each other. These results may support the use of TREG cell-modulating strategies with SBRT to improve the antitumor immune response.

Neutralizing antibody and T-cell responses against SARS-CoV-2 variants by heterologous CoronaVac/ChAdOx-1 vaccination in elderly subjects with chronic obstructive pulmonary disease

BackgroundData on humoral and cellular immune responses against SARS-CoV-2 after receiving heterologous CoronaVac/ChAdOx-1 (CoVac/ChAd) vaccination in subjects with chronic obstructive pulmonary disease (COPD) are still limited. Therefore, we determined the neutralizing antibody (NAb) and T-cell responses against SARS-CoV-2 wild type (WT) and variants of concern (VOCs) in COPD patients. MethodsThe levels of NAb as well as specific CD4 and CD8 T-cell responses against SARS-CoV-2 WT and VOCs were determined in COPD patients before and after vaccination. ResultsFour weeks after vaccinations, the median levels of % inhibition of NAb against SARS-CoV-2 WT, Alpha, Beta, and Delta variants were significantly higher compared to pre-vaccination. The induction of NAb against Omicron was very low compared to other variants. At four weeks after vaccination, in comparison to pre-vaccination, the increasing trend of TNF-α-, IFN-γ-, IL-4-, IL-17-, IL-10-, and FasL-producing CD4 T-cells upon stimulation with WT spike peptides were demonstrated. No difference in T-cell responses to spike peptides of Alpha, Beta, and Delta variants and their WT homologs was observed. ConclusionHeterologous CoVac/ChAd vaccine induced the production of NAb against SARS-CoV-2 WT, Alpha, Beta, and Delta variants, but low for Omicron in COPD patients. Induction of CD4 T-cell subset responses was slightly observed by this vaccine regimen.Clinical Trials Registry: This study was approved by the Clinical Trials Registry (Study ID: TCTR20210822002).

Dynamic mechanism for the ligand discrimination by αβ T-cell receptor enhanced by mechanical load.

TheαβT-Cell Receptor (TCR) enhances recognition of its cognate peptide-bound major histocompatibility complex (pMHC) molecule by activating a catch bond under physiological piconewton-level force. Our recent molecular dynamics (MD) simulations on the JM22 TCR suggest that catch bond activation involves suppressing intra-domain motion by the applied force, thereby stabilizing the TCR-pMHC interface. To further investigate the role of mechanical load in peptide discrimination, we performed all-atom MD simulations of the A6 and B7 TCRs, which share the same TCRβ and bind to the same HLA-A2/Tax pMHC (PDB 1AO7 and 1BD2). For both TCRs, we found that the overall fit of the TCRαβ-pMHC complex was enhanced by applied load in the 19-pN range. High load stabilized contacts between the pMHC and the TCR as well as between TCR subdomains. The two TCRs employed a similar strategy where theα chain was modified more by load compared to the β chain. To assess whether this load-dependent behavior is unique to agonist peptides, we additionally studied A6 TCR bound to peptides bearing point mutations to Tax (PDB 3QFJ, 1QSE, 1QRN, and 1QSF). The TCR in these complexes are structurally very similar in static x-ray structures, yet the mutations lead to differences in T-cell response. For weak agonists, force temporarily maintained TCR-pMHC and TCR contacts, yet the interface exhibited destabilization within the 1-µs simulation time. For antagonists, the applied load did not stabilize TCR domain motion, which was related to significant losses in TCR-pMHC interface contacts. Our simulations reveal an avenue by which the force-based catch bond mechanism selectively works with the cognate peptide antigen.

An extended SARS-CoV-2 mRNA vaccine prime-boost interval enhances B cell immunity with limited impact on T cells

Spacing the first two doses of SARS-CoV-2 mRNA vaccines beyond 3-4weeks raised initial concerns about vaccine efficacy. While studies have since shown that long-interval regimens induce robust antibody responses, their impact on B and Tcell immunity is poorly known. Here, we compare SARS-CoV-2 naive donors B and Tcell responses to two mRNA vaccine doses administered 3-4 versus 16weeks apart. After boost, the longer interval results in a higher magnitude and a more mature phenotype of RBD-specific B cells. While the two geographically distinct cohorts present quantitative and qualitative differences in Tcell responses at baseline and after priming, the second dose led to convergent features with overall similar magnitude, phenotype, and function of CD4+ and CD8+ Tcell responses at post-boost memory time points. Therefore, compared to standard regimens, a 16-week interval has a favorable impact on the B cell compartment but minimally affects Tcell immunity.

Evaluating novel COVID-19 vaccines in the current chapter of the pandemic

Evaluating novel COVID-19 vaccines in the current chapter of the pandemic

Differential T-cell responses in dogs with meningoencephalomyelitis of unknown origin compared to healthy controls.

Meningoencephalomyelitis of unknown origin (MUO) is a common disorder in dogs that results in mononuclear inflammation in the brain and/or spinal cord. MUO is presumed to be autoimmune but specific immunological aberrations have not been identified. This exploratory study aimed to evaluate T cell production of two cytokines commonly implicated in autoimmune disease, interferon-gamma (IFNg) and interleukin-17 (IL17). Peripheral blood mononuclear cells were obtained from 12 dogs with MUO and 10 healthy controls, stimulated to activate intracellular signaling pathways, and stained with a cluster of differentiation 4 (CD4), cluster of differentiation eight (CD8), IFNg, and IL17 antibodies prior to analysis by flow cytometry. Mean differences in absolute cell numbers are represented as MUO cases minus healthy controls, and 95% Cis are reported. Overall IFNg-producing lymphocytes (mean difference = 241.8 cells/ul, 95% CI = 65.6 to 418.1) and CD4+ IFNg-producing T-cells (mean difference = 188.4, 95% CI = 77.3 to 299.5) were fewer in MUO cases. Additionally, CD4+ IL17-producing T-cells were greater in MUO cases (mean difference −34.9, 95% CI = −50.54 to −19.17) and CD8+ IL17-producing T-cells were fewer in MUO cases (mean difference = 73.5, 95% CI = 6.8 to 140.1). These results support that immunological changes can be identified in peripheral blood cells of dogs with MUO and suggest that T-helper type 17 (Th17) cells may play a role in pathogenesis.

Discordant Antibody and T-Cell Responses to the Severe Acute Respiratory Syndrome Coronavirus 2 Omicron Variant in Coronavirus Disease 2019 Messenger RNA Vaccine Recipients.

We compared antibody and T cell responses against the SARS-CoV-2 vaccine strain spike protein to responses against the Omicron variant in 15 mRNA vaccine recipients. While these individuals had significantly lower levels of antibodies that inhibited Omicron spike protein binding to ACE2, there was no difference in T cell responses.

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

ObjectiveSARS-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. MethodsSerological, T-cell ELISpot, cytokines and immunophenotyping 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. ResultsNo significant different differences in T-cell responses were observed 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. 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.

Antibody and T-Cell Responses to COVID-19 Vaccination in Myeloproliferative Neoplasm Patients

▪The efficacy of COVID-19 vaccines in cancer populations remain unknown. Myeloproliferative neoplasms (MPNs), including chronic myeloid leukemia (CML), essential thrombocythemia (ET), polycythemia vera (PV), and myelofibrosis (MF) remain a vulnerable patient population and are immunocompromised due to impaired innate and adaptive immunity, heightened inflammation, and effects of ongoing treatment. We evaluate antibody and T-cell responses in MPN patients following completion of the BNT162b2 (Pfizer/BioNTech) and mRNA-1273 (Moderna) COVID-19 vaccine series.Patients with a known diagnosis of MPN presenting at Massachusetts General Hospital and eligible for COVID-19 vaccination were recruited. All participants gave informed consent and the study protocol was approved by the Institutional Review Board. 33 MPN patients were enrolled and 23 patients completed vaccination. Baseline and post-vaccination peripheral blood samples were collected and peripheral blood mononuclear cells (PBMCs) isolated. 26 vaccinated participants with no history of malignancy were included as healthy controls (PMID 33972942). Baseline characteristics are tabled below.Qualitative ELISA for human IgG/A/M against SARS-CoV-2 spike protein using donor serum was performed per manufacturer instructions. Seroconversion occurred in 22/23 (96%) of MPN patients and 25/26 (96%) of healthy controls (Figure).To measure SARS-CoV-2 T-cell immunity, an IFNγ ELISpot assay previously developed in convalescent and vaccinated healthy individuals was used. Freshly isolated PBMCs from patients were stimulated with commercially available overlapping 15mer peptide pools spanning the SARS-CoV-2 spike and nucleocapsid proteins. Given its size, the spike protein was split into two pools (Spike A or B). IFNγ-producing T-cells were quantified by counting the median spot forming units (SFU) per 2.5x10 5 PBMCs from duplicate wells. A positive threshold was defined as >6 SFUs per 2.5x10 5 PBMCs to either Spike A or B after subtraction of background, based on prior receiver operator curve (ROC) analysis of ELISpot responses (sensitivity 90% specificity 92%).Post-vaccination ELISpot responses occurred in 21/23 (91%) of MPN patients and 26/26 (100%) of healthy controls (p=0.99) (Figure). The median SFU to total spike protein (Spike A+B) increased after vaccination in both MPN patients (0 to 38, p=0.02) and healthy controls (6 to 134, p=0.002). MPN patients had significantly lower median SFU's on post-vaccination ELISpot compared to healthy controls (38 vs 134, p=0.044), although this was not significant after adjusting for age in multivariable logistic regression. MF patients had the lowest seroconversion and ELISpot response rates, and lowest median post-vaccination SFUs, although this was not significant. There were no other differences in post-vaccination SFUs with regards to gender, vaccine type, number of days post-vaccine, treatment, and absolute lymphocyte count.Whole-blood assay based on the in vitro diagnostic QuantiFERON TB Gold Plus assay was also used to assess T-cell response. Heparinized whole blood from donors was stimulated with S1 and S2 subdomains for the SARS-CoV-2 spike protein, with measurement of IFNγ released into plasma with the QuantiFERON ELISA. IFNγ release of >0.3 IU/mL was considered a positive threshold, based on prior ROC analysis (sensitivity and specificity 100%). MPN patients had significantly lower IFNγ response rates compared to healthy controls (57% versus 100%, p=0.003) (Figure).Our findings demonstrate robust antibody and T-cell responses to BNT162b2 and mRNA-1273 vaccination in MPN patients, with >90% serologic and ELISpot responder rates. We detected subtle differences in T-cell responses in MPN patients compared to healthy controls. MPN patients had lower median post-vaccination ELISpot SFUs and lower rates of T-cell responses on IFNγ-whole blood assay compared to healthy controls. As the whole blood assay uses whole protein antigen rather than peptide pools, differences from ELISpot testing may reflect deficiencies in antigen processing and presentation. It is unclear whether these subtle differences translate into less clinical protection from COVID-19, or to what extent our results are confounded by the older age of MPN patients. Further evaluation of B and T-cell responses to COVID-19 vaccination in a larger sample size of MPN patients is warranted. [Display omitted] DisclosuresNeuberg: Pharmacyclics: Research Funding; Madrigal Pharmaceuticals: Other: Stock ownership. Maus: Atara: Consultancy; Bayer: Consultancy; BMS: Consultancy; Cabaletta Bio (SAB): Consultancy; CRISPR therapeutics: Consultancy; In8bio (SAB): Consultancy; Intellia: Consultancy; GSK: Consultancy; Kite Pharma: Consultancy, Research Funding; Micromedicine: Consultancy, Current holder of stock options in a privately-held company; Novartis: Consultancy; Tmunity: Consultancy; Torque: Consultancy, Current holder of stock options in a privately-held company; WindMIL: Consultancy; AstraZeneca: Consultancy; Agenus: Consultancy; Arcellx: Consultancy; Astellas: Consultancy; Adaptimmune: Consultancy; tcr2: Consultancy, Divested equity in a private or publicly-traded company in the past 24 months; century: Current equity holder in publicly-traded company; ichnos biosciences: Consultancy, Current holder of stock options in a privately-held company. Hobbs: AbbVie.: Consultancy; Incyte Corporation: Research Funding; Novartis: Consultancy; Bayer: Research Funding; Merck: Research Funding; Constellation Pharmaceuticals: Consultancy, Research Funding; Celgene/Bristol Myers Squibb: Consultancy.

Anti–SARS-CoV-2 Antibody Responses in Patients With IBD Treated With Biologics: Are We Finding CLARITY?

Anti–SARS-CoV-2 Antibody Responses in Patients With IBD Treated With Biologics: Are We Finding CLARITY?

The role of MKK4 in T-cell development and immunity to viral infections.

The stress‐activated protein kinases (SAPKs)/c‐Jun‐N‐terminal‐kinases (JNK) are members of the mitogen‐activated protein kinase family. These kinases are responsible for transducing cellular signals through a phosphorylation‐dependent signaling cascade. JNK activation in immune cells can lead to a range of critical cellular responses that include proliferation, differentiation and apoptosis. MKK4 is a SAPK that can activate both JNK1 and JNK2; however, its role in T‐cell development and function has been controversial. Additionally, loss of either JNK1 or JNK2 has opposing effects in the generation of T‐cell immunity to viral infection and cancer. We used mice with a conditional loss of MKK4 in T cells to investigate the in vivo role of MKK4 in T‐cell development and function during lymphocytic choriomeningitis virus (LCMV) infection. We found no physiologically relevant differences in T‐cell responses or immunity to either acute or chronic LCMV in the absence of MKK4.

Comparison of immunogenicity and safety outcomes of a malaria vaccine FMP013/ALFQ in rhesus macaques (Macaca mulatta) of Indian and Chinese origin

BackgroundIndian-origin rhesus (InR) are preferred for research, but strict export restrictions continue to limit their use. Chinese-origin rhesus (ChR), although easier to procure, are genetically distinct from InR and differ in their immune response to infectious agents, such as the Simian Immunodeficiency Virus. The most advanced malaria vaccine, RTS,S (GlaxoSmithKline), is based on the circumsporozoite protein (CSP) of Plasmodium falciparum. The efficacy of RTS,S vaccine in the field remains low and short-lived; efforts are underway to improve CSP-based vaccines. Rhesus models can accelerate preclinical down-selection of the next generation of malaria vaccines. This study was used to determine if the safety and immunogenicity outcomes following vaccination with a CSP vaccine would differ in the InR and ChR models, given the genetic differences between the two sub-populations of rhesus.MethodsThe FMP013 vaccine, was composed of nearly full-length soluble P. falciparum CSP produced in Escherichia coli and was adjuvanted with the Army liposomal formulation (ALFQ). Three doses of the vaccine were administered in InR and ChR (n = 6) at 1-month intervals and the antibody and T cell responses were assessed.ResultsLocal and systemic toxicity profile of FMP013 vaccine in InR and ChR were similar and they revealed that the FMP013 vaccine was safe and caused only mild and transient inflammatory adverse reactions. Following the first 2 vaccines, there was a slower acquisition of antibodies to the CSP repeat region in ChR. However after the 3rd vaccination the titers in the two models were comparable. The ChR group repeat-specific antibodies had higher avidity and ChR group showed higher inhibition of liver stage development activity compared to InR. There was no difference in T-cell responses to the FMP013 vaccine between the two models.ConclusionsA difference in the quality of serological responses was detected between the two sub-populations of rhesus. However, both models confirmed that FMP013/ALFQ vaccine was safe, highly immunogenic, elicited functional antibodies and T-cell responses. Overall, the data suggests that rhesus of Indian and Chinese origins can be interchangeably used to compare the safety and immunogenicity of next-generation of malaria vaccines and adjuvants.

T-Cell Clonal Expansion and Activation Associated with Durable Clinical Response to Dual BTK and CDK4/6 Inhibitor Therapy in Mantle Cell Lymphoma

T-Cell Clonal Expansion and Activation Associated with Durable Clinical Response to Dual BTK and CDK4/6 Inhibitor Therapy in Mantle Cell Lymphoma

Salivary gland immunization via Wharton's duct activates differential T-cell responses within the salivary gland immune system.

Salivary glands are a major component of the mucosal immune system that confer adaptive immunity to mucosal pathogens. As previously demonstrated, immunization of the submandibular gland with tissue culture-derived murine cytomegalovirus (tcMCMV) or replication-deficient adenoviruses expressing individual murine cytomegalovirus (MCMV) genes protected mice against a lethal MCMV challenge. Here, we report that salivary gland inoculation of BALB/cByJ mice with tcMCMV or recombinant adenoviruses differentially activates T helper (Th)1, -2, and -17 cells in the salivary glands vs. the associated lymph nodes. After inoculation with tcMCMV, lymphocytes from the submandibular gland preferentially express the transcription factor T-cell-specific T-box transcription factor (T-bet), which controls the expression of the hallmark Th1 cytokine, IFN-γ. Lymphocytes from the periglandular lymph nodes (PGLNs) express both T-bet and GATA-binding protein 3 (GATA3), which promotes the secretion of IL-4, -5, and -10 from Th2 cells. In contrast, after inoculation with replication-deficient adenoviruses, lymphocytes from the submandibular gland express T-bet, GATA3, and RAR-related orphan receptor γ, thymus-specific isoform (RORγt) (required for differentiation of Th17 cells) and forkhead box P3 (Foxp3) (required for the differentiation of regulatory T cells). Lymphocytes from the PGLNs were not activated. The differential induction of Th responses in the salivary gland vs. the PGLNs after inoculation with attenuated virus vs. a nominal protein antigen supports the use of the salivary as an alternative mucosal route for administering vaccines.-Liu, G., Zhang, F., Wang, R., London, S. D., London, L. Salivary gland immunization via Wharton's duct activates differential T-cell responses within the salivary gland immune system.

2572. Decreased T-Cell Response, but Appropriate Antibody Production to Tetanus Vaccine Among HIV-Exposed Uninfected Infants in Botswana

BackgroundIn Botswana, more than 10% of HIV-exposed, uninfected infants (HEU) are hospitalized or die in the first 6 months of life, largely due to infectious causes. Vaccine responses can act as a marker of the immune response to infectious antigens. Previous studies of vaccine responses in HEU have had conflicting results. We compared T-cell responses to tetanus and purified protein derivative (PPD), and antibody titers to tetanus, between HEU and HIV-unexposed infants (HUU).MethodsA total of 443 HIV-infected and 451 HIV-uninfected mothers and their 453 HEU/457 HUU live-born infants were followed from pregnancy/delivery through 24 months postpartum in a prospective observational study in Botswana (“Tshipidi”). T-cell expression of interferon (IFN)-γ and interleukin (IL)-2 were measured at 6 months using FluoroSpot after stimulation with tetanus toxoid or PPD. Quantitative tetanus toxoid IgG was measured in plasma at 18 months using ELISA. Mean spot-forming units (sfu) per 105 cells and geometric mean antibody titers were compared between HEU and HUU infants who had received 3 doses of tetanus and 1 dose of Bacille Calmette–Guérin (BCG) vaccines by 6 months, and 3 or 4 doses of tetanus vaccine by 18 months. Results. Peripheral blood mononuclear cells were available at 6 months for 63 HEU and 18 HUU. Plasma was available at 18 months for 39 HEU and 42 HUU. HEU infants had significantly lower IL-2 expression after tetanus stimulation than HUU infants (4.4 vs. 16.1 sfu/105 cells, P = 0.004; figure), but no difference in IFNγ expression. There were no differences in T-cell responses to PPD between HEU and HUU. There were no differences in tetanus geometric mean antibody titers between HEU and HUU. Conclusion. In this cohort of infants from Botswana, we found decreased T-cell responses, but not antibody responses, to tetanus toxoid and no differences in T-cell responses to PPD. Cell-mediated immune defects may play a greater role than humoral immune defects in the increased susceptibility to infection among HEU. BCG vaccine produces robust T-helper 1 responses, which may overcome cell-mediated immune defects in HEU. Disclosures All authors: No reported disclosures.