scholarly journals Tumor-Derived Autophagosomes (DRibbles) Activate Human B Cells to Induce Efficient Antigen-Specific Human Memory T-Cell Responses

2021 ◽  
Vol 12 ◽  
Author(s):  
Hongyan Ren ◽  
Tianyu Zhang ◽  
Yongren Wang ◽  
Qi Yao ◽  
Ziyu Wang ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
Tumor Antigens ◽  
High Mobility ◽  
Human Memory ◽  
Hematopoietic Growth Factors ◽  
Cell Responses ◽  
Specific Memory ◽  
Human B Cells ◽  
Membrane Bound

We have reported that tumor-derived autophagosomes (DRibbles) were efficient carriers of tumor antigens and DRibbles antigens could be present by DRibbles-activated B cells to stimulate effect and naïve T cells in mice. However, the effect of DRibbles on human B cells remains unclear. Herein, we found that DRibbles can also efficiently induce proliferation and activation of human B cells and lead to the production of chemokines, cytokines and hematopoietic growth factors. We further demonstrated human B cells can effectively phagocytose DRibbles directly and cross-present DRibbles antigens to stimulate antigen-specific memory T cells. Furthermore, we found that membrane-bound high-mobility group B1 (HMGB1) on DRibbles was crucial for inducing human B cells activation. Therefore, these findings provide further evidence to promote the clinical application of B-DRibbles vaccines.

scholarly journals COVID-19 convalescents exhibit deficient humoral and T cell responses to variant of concern Spike antigens at 12 month post-infection

2021 ◽  
Author(s):  
Pablo Garcia-Valtanen ◽  
Christopher Martin Hope ◽  
Makutiro Ghislain Masavuli ◽  
Arthur Eng Lip Yeow ◽  
Harikrishnan Balachandran ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Post Infection ◽  
T Cell Responses ◽  
Memory B Cells ◽  
Pseudotyped Virus ◽  
Cell Responses ◽  
Specific Memory ◽  
Cell Functionality

Background The duration and magnitude of SARS-CoV-2 immunity after infection, especially with regard to the emergence of new variants of concern (VoC), remains unclear. Here, immune memory to primary infection and immunity to VoC was assessed in mild-COVID-19 convalescents one year after infection and in the absence of viral re-exposure or COVID-19 vaccination. Methods Serum and PBMC were collected from mild-COVID-19 convalescents at ~6 and 12 months after a COVID-19 positive PCR (n=43) and from healthy SARS-CoV-2-seronegative controls (n=15-40). Serum titers of RBD and Spike-specific Ig were quantified by ELISA. Virus neutralisation was assessed against homologous, pseudotyped virus and homologous and VoC live viruses. Frequencies of Spike and RBD-specific memory B cells were quantified by flow cytometry. Magnitude of memory T cell responses was quantified and phenotyped by activation-induced marker assay, while T cell functionality was assessed by intracellular cytokine staining using peptides specific to homologous Spike virus antigen and four VoC Spike antigens. Findings At 12 months after mild-COVID-19, >90% of convalescents remained seropositive for RBD-IgG and 88.9% had circulating RBD-specific memory B cells. Despite this, only 51.2% convalescents had serum neutralising activity against homologous live-SARS-CoV-2 virus, which decreased to 44.2% when tested against live B.1.1.7, 4.6% against B.1.351, 11.6% against P.1 and 16.2%, against B.1.617.2 VoC. Spike and non-Spike-specific T cells were detected in >50% of convalescents with frequency values higher for Spike antigen (95% CI, 0.29-0.68% in CD4+ and 0.11-0.35% in CD8+ T cells), compared to non-Spike antigens. Despite the high prevalence and maintenance of Spike-specific T cells in Spike 'high-responder' convalescents at 12 months, T cell functionality, measured by cytokine expression after stimulation with Spike epitopes corresponding to VoC was severely affected. Interpretations SARS-CoV-2 immunity is retained in a significant proportion of mild COVID-19 convalescents 12 months post-infection in the absence of re-exposure to the virus. Despite this, changes in the amino acid sequence of the Spike antigen that are present in current VoC result in virus evasion of neutralising antibodies, as well as evasion of functional T cell responses.

scholarly journals Interferon lambda 4 can directly activate human CD19+ B cells and CD8+ T cells

2020 ◽  
Vol 4 (1) ◽  
pp. e201900612
Author(s):  
Mairene Coto-Llerena ◽  
Marco Lepore ◽  
Julian Spagnuolo ◽  
Daniela Di Blasi ◽  
Diego Calabrese ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
T Cell Responses ◽  
Spontaneous Clearance ◽  
Type I ◽  
Cell Responses ◽  
Human B Cells ◽  
Human T Cells ◽  
Liver Biopsies

Compared with the ubiquitous expression of type I (IFNα and IFNβ) interferon receptors, type III (IFNλ) interferon receptors are mainly expressed in epithelial cells of mucosal barriers of the of the intestine and respiratory tract. Consequently, IFNλs are important for innate pathogen defense in the lung and intestine. IFNλs also determine the outcome of hepatitis C virus (HCV) infections, with IFNλ4 inhibiting spontaneous clearance of HCV. Because viral clearance is dependent on T cells, we explored if IFNλs can directly bind to and regulate human T cells. We found that human B cells and CD8+ T cells express the IFNλ receptor and respond to IFNλs, including IFNλ4. IFNλs were not inhibitors but weak stimulators of B- and T-cell responses. Furthermore, IFNλ4 showed neither synergistic nor antagonistic effects in co-stimulatory experiments with IFNλ1 or IFNα. Multidimensional flow cytometry of cells from liver biopsies of hepatitis patients from IFNλ4-producers showed accumulation of activated CD8+ T cells with a central memory-like phenotype. In contrast, CD8+ T cells with a senescent/exhausted phenotype were more abundant in IFNλ4–non-producers. It remains to be elucidated how IFNλ4 promotes CD8 T-cell responses and inhibits the host immunity to HCV infections.

Induction of CD4+ T-cell anergy and apoptosis by activated human B cells

Blood ◽  
2008 ◽  
Vol 112 (12) ◽  
pp. 4555-4564 ◽  
Author(s):  
Theresa Tretter ◽  
Ram K. C. Venigalla ◽  
Volker Eckstein ◽  
Rainer Saffrich ◽  
Serkan Sertel ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Cell Contact ◽  
Activated T Cells ◽  
Cell Responses ◽  
T Cell Anergy ◽  
Human B Cells ◽  
Cell Anergy

Abstract B cells are well-known mediators of humoral immunity and serve as costimulators in the generation of T cell–mediated responses. In several mouse models, however, it was observed that B cells can also down-regulate immune reactions, suggesting a dual role for B cells. Due to this discrepancy and so far limited data, we directly tested the effects of primary human B cells on activated CD4+ T helper cells in vitro. We found that under optimal costimulation large, activated CD25+ B cells but not small CD25− B cells induced temporary T-cell anergy, determined by cell division arrest and down-regulation of cytokine production. In addition, large CD25+ B cells directly induced CD95-independent apoptosis in a subpopulation of activated T cells. Suppression required direct B-T-cell contact and was not transferable from T to T cell, excluding potential involvement of regulatory T cells. Moreover, inhibitory effects involved an IL-2–dependent mechanism, since decreasing concentrations of IL-2 led to a shift from inhibitory toward costimulatory effects triggered by B cells. We conclude that activated CD25+ B cells are able to costimulate or down-regulate T-cell responses, depending on activation status and environmental conditions that might also influence their pathophysiological impact.

scholarly journals B cell depletion impairs vaccination-induced CD8+ T cell responses in a type I interferon-dependent manner

2021 ◽  
pp. annrheumdis-2021-220435
Author(s):  
Theresa Graalmann ◽  
Katharina Borst ◽  
Himanshu Manchanda ◽  
Lea Vaas ◽  
Matthias Bruhn ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cell Expansion ◽  
De Novo ◽  
T Cell Responses ◽  
Type I ◽  
Cell Responses ◽  
T Cell Expansion

ObjectivesThe monoclonal anti-CD20 antibody rituximab is frequently applied in the treatment of lymphoma as well as autoimmune diseases and confers efficient depletion of recirculating B cells. Correspondingly, B cell-depleted patients barely mount de novo antibody responses during infections or vaccinations. Therefore, efficient immune responses of B cell-depleted patients largely depend on protective T cell responses.MethodsCD8+ T cell expansion was studied in rituximab-treated rheumatoid arthritis (RA) patients and B cell-deficient mice on vaccination/infection with different vaccines/pathogens.ResultsRituximab-treated RA patients vaccinated with Influvac showed reduced expansion of influenza-specific CD8+ T cells when compared with healthy controls. Moreover, B cell-deficient JHT mice infected with mouse-adapted Influenza or modified vaccinia virus Ankara showed less vigorous expansion of virus-specific CD8+ T cells than wild type mice. Of note, JHT mice do not have an intrinsic impairment of CD8+ T cell expansion, since infection with vaccinia virus induced similar T cell expansion in JHT and wild type mice. Direct type I interferon receptor signalling of B cells was necessary to induce several chemokines in B cells and to support T cell help by enhancing the expression of MHC-I.ConclusionsDepending on the stimulus, B cells can modulate CD8+ T cell responses. Thus, B cell depletion causes a deficiency of de novo antibody responses and affects the efficacy of cellular response including cytotoxic T cells. The choice of the appropriate vaccine to vaccinate B cell-depleted patients has to be re-evaluated in order to efficiently induce protective CD8+ T cell responses.

scholarly journals Mice with the xid defect have helper cells for T15 idiotype-dominant anti-phosphorylcholine primary and secondary plaque-forming cells responses.

1982 ◽  
Vol 155 (4) ◽  
pp. 1245-1250 ◽  
Author(s):  
J Quintáns ◽  
Z S Quan ◽  
M A Arias
Keyword(s):  
T Cells ◽  
B Cells ◽  
Helper T Cells ◽  
Normal Female ◽  
Male And Female ◽  
Female Mice ◽  
Cell Responses ◽  
Helper Cells ◽  
Helper Activity

We have examined the abilities of helper T cells from commercially available (CBA/N X BALB/c)F1 (NBF1) xid male and phenotypically normal female mice to help T15+ and T15- B cells to produce thymus-dependent phosphorylcholine (PC)-specific direct plaque-forming cell responses. Carrier-primed T cells from both male and female mice were found (a) to restore T15+ TD responses in congenitally athymic BALB/c mice, (b) to help PC-primed BALB/c splenic B cells produce predominantly T15+ responses, and (c) to provide help for T15+ and T15- PFC responses generated by PC-primed normal F1 splenic B cells. Furthermore, carrier-primed irradiated xid and normal recipients contributed adequate helper activity for T15 dominant responses. We therefore conclude that male and female NBF1 mice are equally capable of helping T15+ responses.

scholarly journals 912 Preferential recognition of neoantigens over non-canonical peptides in cancer patients

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A958-A958
Author(s):  
Maria Lozano-Rabella ◽  
Andrea Garcia-Garijo ◽  
Jara Palomero ◽  
Florian Erhard ◽  
Juan Martín-Liberal ◽  
...  
Keyword(s):  
T Cells ◽  
Tumor Cell ◽  
Somatic Mutations ◽  
Tumor Antigens ◽  
Tumor Rejection ◽  
Tumor Cell Lines ◽  
Coding Regions ◽  
Cell Responses ◽  
Whole Exome

BackgroundDespite recent advances in exome and RNA sequencing to identify tumor-rejection antigens including neoantigens, the existing techniques fail to identify the vast majority of antigens targeted by tumor-reactive cells. A growing number of studies suggest that HLA-I peptides derived from non-canonical (nonC) open reading frames or derived from allegedly non-coding regions can contribute to tumor immunogenicity. Here we use proteogenomics to identify personalized candidate canonical and non-canonical tumor-rejection antigens and to evaluate their contribution to cancer immune surveillance in patients.MethodsWhole exome sequencing was performed to identify the non-synonymous somatic mutations (NSM) and immunopeptidomics to identify the HLA-I presented peptides (pHLA) in 9 patient-derived tumor cell lines (TCL). Peptid-PRISM proteogenomics pipeline was used to identify both canonical and non-canonical pHLA, including those derived from NSM in coding regions. All peptides containing mutations and derived from either cancer-testis (CTA) or tumor-associated antigens (TAA) were selected as candidate tumor antigens. For nonC peptides, an immunopeptidomics healthy dataset containing several tissues and HLA-allotypes was used to eliminate those derived from normal ORFs and select nonC peptides preferentially expressed in tumor cells (nonC-TE). The selected candidate peptides were synthesized, pulsed onto autologous APCs and co-cultured with tumor-reactive ex vivo expanded lymphocytes to assess immune recognition (figure 1).ResultsNonC-TE peptides were identified in all TCL studied, ranging from 0.5% to 5.4% of the total HLA-I presented peptides (n= 506). As described previoulsy, 5’UTR were the main source. Of note, the tumor type did not have an impact on the frequency of presented nonC peptides, but rather the presence of HLA-A*11:01 and HLA-A*03:01 was a major determinant. T cell responses were detected against at least 13/33 putative neoantigens, 2/24 CTA and 2/61 TAA. On the contrary, none of the 471 nonC-TE candidate peptides tested thus far, including one containing a NSM were able to elicit a recall immune response. Nevertheless, T cells recognizing at least 3 of them were detected through in vitro sensitization of non-autologous PBMCs.Abstract 912 Figure 1Workflow diagramTumor biopsies and blood samples are obtained from cancer patients (left panel). Patient-derived tumor cell lines are generated in vitro, the peptides presented on HLA molecules are further isolated and analyzed in a mass-spectrometer (top panel). Whole exome sequencing (WES) from matched tumor and healthy tissue is performed to identify the non-synonymous somatic mutations (NSM) (middle panel). Peptide-PRISM proteogenomics pipeline combines the information from the immunopeptidomics data and WES to identify pHLA sequences from both canonical and non-canonical candidate tumor antigens (top right panel). Lymphocyte populations either TILs or sorted PBMCs are expanded and further screened for pre-existing T cell responses (bottom panel) against the candidate epitopes by co-culturing the T cells with peptide-pulsed autologous APC. The recognition is assessed by measuring IFNg release by elispot and the upregulation of activation surface markers by FACS (bottom right panel).ConclusionsOur results show that although HLA-I nonC peptides were frequently presented in all TCLs studied and they can be immunogenic, neoantigens derived from mutations in canonical coding regions were preferentially recognized by tumor-reactive lymphocytes, suggesting T cells targeting the latter are primed more efficiently. The identification of mutated nonC antigens using whole genome sequencing to identify mutations in non-coding regions warrants further examination. Still, the specificity of many tumor-reactive TILs remains unknown.Ethics Approval”This study was approved by the ”Comité de Ética de Investigación con Medicamentos del Hospital Universitario Vall d’Hebron” institution’s Ethics Board; approval number PR(AG)537/2019.”

scholarly journals B cell depletion with anti-CD20 mAb exacerbates anti-donor CD4+ T cell responses in highly sensitized transplant recipients

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Asuka Tanaka ◽  
Kentaro Ide ◽  
Yuka Tanaka ◽  
Masahiro Ohira ◽  
Hiroyuki Tahara ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
T Cell Responses ◽  
Cell Depletion ◽  
B Cell Depletion ◽  
Transplant Recipients ◽  
Cell Responses ◽  
Anti Cd20

AbstractPretransplant desensitization with rituximab has been applied to preformed donor-specific anti-human leukocyte antigen antibody (DSA)-positive recipients for elimination of preformed DSA. We investigated the impact of pretransplant desensitization with rituximab on anti-donor T cell responses in DSA-positive transplant recipients. To monitor the patients’ immune status, mixed lymphocyte reaction (MLR) assays were performed before and after desensitization with rituximab. Two weeks after rituximab administration, the stimulation index (SI) of anti-donor CD4+ T cells was significantly higher in the DSA-positive recipients than in the DSA-negative recipients. To investigate the mechanisms of anti-donor hyper responses of CD4+ T cells after B cell depletion, highly sensitized mice models were injected with anti-CD20 mAb to eliminate B cells. Consistent with clinical observations, the SI values of anti-donor CD4+ T cells were significantly increased after anti-CD20 mAb injection in the sensitized mice models. Adding B cells isolated from untreated sensitized mice to MLR significantly inhibited the enhancement of anti-donor CD4+ T cell response. The depletion of the CD5+ B cell subset, which exclusively included IL-10-positive cells, from the additive B cells abrogated such inhibitory effects. These findings demonstrate that IL-10+ CD5+ B cells suppress the excessive response of anti-donor CD4+ T cells responses in sensitized recipients.

scholarly journals PD-1+ Tim3+ tumor-infiltrating CD8 T cells sustain the potential for IFN-γ production, but lose cytotoxic activity in ovarian cancer

2020 ◽  
Vol 32 (6) ◽  
pp. 397-405 ◽  
Author(s):  
Masaaki Sawada ◽  
Kumiko Goto ◽  
Akiko Morimoto-Okazawa ◽  
Miya Haruna ◽  
Kei Yamamoto ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
T Cells ◽  
Poor Prognosis ◽  
Tumor Antigens ◽  
Cytokine Production ◽  
Intracellular Cytokine Staining ◽  
Target Cell Line ◽  
Direct Cytotoxicity ◽  
Membrane Bound ◽  
Ifn Γ

Abstract Persistent exposure to tumor antigens results in exhausted tumor-infiltrating T cells (TILs) that express the immune checkpoint molecules, PD-1 and Tim3, and lack anti-tumor immunity. To examine the exhausted status of TILs in ovarian cancer, the potential for cytokine production, proliferation and cytotoxicity by purified PD-1+ Tim3+ CD8 TILs was assessed. The production of IFN-γ and TNF-α by PD-1+ Tim3+ CD8 TILs remained the same in an intracellular cytokine staining assay and was higher in a cytokine catch assay than that by PD-1− Tim3− and PD-1+ Tim3− CD8 TILs. %Ki67+ was higher in PD-1+ Tim3+ CD8 TILs than in PD-1− Tim3− CD8 TILs. However, patients with high PD-1+ Tim3+ CD8 TILs had a poor prognosis. The potential for cytotoxicity was then examined. %Perforin+ and %granzyme B+ were lower in PD-1+ Tim3+ CD8 TILs than in PD-1− Tim3− and PD-1+ Tim3− CD8 TILs. To observe the potential for direct cytotoxicity by T cells, a target cell line expressing membrane-bound anti-CD3scFv was newly established and a cytotoxic assay targeting these cells was performed. The cytotoxicity of PD-1+ Tim3+ CD8 TILs was significantly lower than that of PD-1− Tim3− and PD-1+ Tim3− CD8 TILs. Even though PD-1+ Tim3+ CD8 TILs in ovarian cancer showed a sustained potential for cytokine production and proliferation, cytotoxicity was markedly impaired, which may contribute to the poor prognosis of patients with ovarian cancer. Among the impaired functions of exhausted TILs, cytotoxicity may be an essential target for cancer immunotherapy.

scholarly journals Memory B Cell Responses to Vibrio cholerae O1 Lipopolysaccharide Are Associated with Protection against Infection from Household Contacts of Patients with Cholera in Bangladesh

2012 ◽  
Vol 19 (6) ◽  
pp. 842-848 ◽  
Author(s):  
Sweta M. Patel ◽  
Mohammad Arif Rahman ◽  
M. Mohasin ◽  
M. Asrafuzzaman Riyadh ◽  
Daniel T. Leung ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Vibrio Cholerae ◽  
Memory B Cells ◽  
Content Type ◽  
Cell Responses ◽  
Household Contacts ◽  
Specific Memory ◽  
Specific Igg ◽  
Protection Against Infection

ABSTRACTVibrio choleraeO1 causes cholera, a dehydrating diarrheal disease. We have previously shown thatV. cholerae-specific memory B cell responses develop after cholera infection, and we hypothesize that these mediate long-term protective immunity against cholera. We prospectively followed household contacts of cholera patients to determine whether the presence of circulatingV. choleraeO1 antigen-specific memory B cells on enrollment was associated with protection againstV. choleraeinfection over a 30-day period. Two hundred thirty-six household contacts of 122 index patients with cholera were enrolled. The presence of lipopolysaccharide (LPS)-specific IgG memory B cells in peripheral blood on study entry was associated with a 68% decrease in the risk of infection in household contacts (P= 0.032). No protection was associated with cholera toxin B subunit (CtxB)-specific memory B cells or IgA memory B cells specific to LPS. These results suggest that LPS-specific IgG memory B cells may be important in protection against infection withV. choleraeO1.

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