scholarly journals Seroconversion following COVID-19 vaccination: Can we optimize protective response in CD20-treated individuals?

2021 ◽  
Author(s):  
David Baker ◽  
Amy MacDougall ◽  
Angray S Kang ◽  
Klaus Schmierer ◽  
Gavin Giovannoni ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Severe Disease ◽  
Neutralizing Antibody ◽  
Vaccine Responses ◽  
Increased Risk ◽  
Cell Monitoring ◽  
Treatment Onset ◽  
Anti Cd20 ◽  
Dosing Intervals

Abstract Although there is an ever-increasing number of disease-modifying treatments for relapsing multiple sclerosis (MS), few appear to influence COVID-19 severity. There is concern about the use of anti-CD20-depleting monoclonal antibodies, due to the apparent increased risk of severe disease following SARS-CoV-2 infection and inhibition of protective anti-COVID-19 vaccine responses. These antibodies are given as maintenance infusions/injections and cause persistent depletion of CD20+ B cells, notably memory B cell populations that may be instrumental in the control of relapsing MS. However, they also continuously deplete immature and mature/naïve B cells that form the precursors for infection-protective antibody responses, thus blunting vaccine responses. Seroconversion and maintained SARS-CoV-2 neutralizing antibody levels provide protection from COVID-19. However, it is evident that poor-seroconversion occurs in the majority of individuals following initial and booster COVID-19 vaccinations, based on standard 6-monthly dosing intervals. Seroconversion may be optimized in the anti-CD20-treated population by vaccinating prior to treatment-onset or using extended/delayed interval dosing (3-6 month extension to dosing interval) in those established on therapy, with B cell monitoring until (1-3%) B cell repopulation occurs prior to vaccination. Some people will take more than a year to replete and therefore protection may depend on either the vaccine-induced T cell responses that typically occur or may require prophylactic, or rapid post-infection therapeutic, antibody or small molecule anti-viral treatment to optimise protection against COVID-19. Further studies are warranted to demonstrate the safety and efficacy of such approaches and whether or not immunity wanes prematurely as has been observed in the other populations.

scholarly journals Durable SARS-CoV-2 B cell immunity after mild or severe disease

2020 ◽  
Author(s):  
Clinton O. Ogega ◽  
Nicole E. Skinner ◽  
Paul W. Blair ◽  
Han-Sol Park ◽  
Kirsten Littlefield ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Humoral Immunity ◽  
Neutralizing Antibodies ◽  
Severe Disease ◽  
Flow Cytometric Analysis ◽  
Neutralizing Antibody ◽  
Cell Mediated Immunity ◽  
Specific Class ◽  
Cell Immunity

AbstractMultiple studies have shown loss of SARS-CoV-2 specific antibodies over time after infection, raising concern that humoral immunity against the virus is not durable. If immunity wanes quickly, millions of people may be at risk for reinfection after recovery from COVID-19. However, memory B cells (MBC) could provide durable humoral immunity even if serum neutralizing antibody titers decline. We performed multi-dimensional flow cytometric analysis of S protein receptor binding domain (S-RBD)-specific MBC in cohorts of ambulatory COVID-19 patients with mild disease, and hospitalized patients with moderate to severe disease, at a median of 54 (39-104) days after onset of symptoms. We detected S-RBD-specific class-switched MBC in 13 out of 14 participants, including 4 of the 5 participants with lowest plasma levels of anti-S-RBD IgG and neutralizing antibodies. Resting MBC (rMBC) made up the largest proportion of S-RBD-specific class-switched MBC in both cohorts. FCRL5, a marker of functional memory when expressed on rMBC, was dramatically upregulated on S-RBD-specific rMBC. These data indicate that most SARS-CoV-2-infected individuals develop S-RBD-specific, class-switched MBC that phenotypically resemble germinal center-derived B cells induced by effective vaccination against other pathogens, providing evidence for durable B cell-mediated immunity against SARS-CoV-2 after recovery from mild or severe COVID-19 disease.Graphical Abstract

scholarly journals Antigenic modulation limits the efficacy of anti-CD20 antibodies: implications for antibody selection

Blood ◽  
2010 ◽  
Vol 115 (25) ◽  
pp. 5191-5201 ◽  
Author(s):  
Stephen A. Beers ◽  
Ruth R. French ◽  
H. T. Claude Chan ◽  
Sean H. Lim ◽  
Timothy C. Jarrett ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Type I ◽  
Type Ii ◽  
Antigenic Modulation ◽  
Lymphatic Leukemia ◽  
Human B Cells ◽  
Anti Cd20

Abstract Rituximab, a monoclonal antibody that targets CD20 on B cells, is now central to the treatment of a variety of malignant and autoimmune disorders. Despite this success, a substantial proportion of B-cell lymphomas are unresponsive or develop resistance, hence more potent anti-CD20 monoclonal antibodies (mAbs) are continuously being sought. Here we demonstrate that type II (tositumomab-like) anti-CD20 mAbs are 5 times more potent than type I (rituximab-like) reagents in depleting human CD20 Tg B cells, despite both operating exclusively via activatory Fcγ receptor–expressing macrophages. Much of this disparity in performance is attributable to type I mAb-mediated internalization of CD20 by B cells, leading to reduced macrophage recruitment and the degradation of CD20/mAb complexes, shortening mAb half-life. Importantly, human B cells from healthy donors and most cases of chronic lymphatic leukemia and mantle cell lymphoma, showed rapid CD20 internalization that paralleled that seen in the Tg mouse B cells, whereas most follicular lymphoma and diffuse large B-cell lymphoma cells were far more resistant to CD20 loss. We postulate that differences in CD20 modulation may play a central role in determining the relative efficacy of rituximab in treating these diseases and strengthen the case for focusing on type II anti-CD20 mAb in the clinic.

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.

Cellular side of acquired immunity (B cells)

2013 ◽  
pp. 371-378
Author(s):  
Thomas Dörner ◽  
Peter E. Lipsky
Keyword(s):  
B Cells ◽  
B Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Plasma Cells ◽  
Adaptive Immune System ◽  
Adaptive Immune ◽  
B Cell Homeostasis ◽  
Anti Cd20 ◽  
Antigen Presenting

B cells have gained interest in rheumatoid arthritis (RA) beyond being the precursors of antibody-producing plasma cells since they are also a broader component of the adaptive immune system. They are capable of functioning as antigen-presenting cells for T-cell activation and can produce an array of cytokines. Disturbances of peripheral B-cell homeostasis together with the formation of ectopic lymphoid neogenesis within the inflamed synovium appears to be a characteristic of patients with RA. Enhanced generation of memory B cells and autoreactive plasma cells producing IgM-RF and ACPA-IgG antibodies together with formation of immune complexes contribute to the maintenance of RA, whereas treatment with B-cell-directed anti-CD20 and CLTA4-Ig therapy provides clinical benefit.

scholarly journals P54 Pneumocystis jirovecii prophylaxis in patients on rituximab

Rheumatology ◽  
2019 ◽  
Vol 58 (Supplement_4) ◽  
Author(s):  
Kishore Warrier1 ◽  
Catherine Salvesani ◽  
Samundeeswari Deepak
Keyword(s):  
Risk Factors ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Conflicts Of Interest ◽  
Pneumocystis Jirovecii ◽  
Current Evidence ◽  
Pneumocystis Jirovecii Pneumonia ◽  
Number Of Patients ◽  
Increased Risk

Abstract Background Rituximab is a chimeric monoclonal antibody that depletes the B cell population by targeting cells bearing the CD20 surface marker and is used widely in the management of paediatric rheumatological conditions like juvenile systemic lupus erythematosus (JSLE), juvenile dermatomyositis (JDM), mixed connective tissue disease (MCTD) and juvenile idiopathic arthritis (JIA). Pneumocystis jirovecii pneumonia (PCP) is a potentially fatal opportunistic infection associated with congenital and acquired defects in T cell–mediated immunity. Our guideline did not recommend prophylaxis against PCP for patients on rituximab, unlike patients on cyclophosphamide, who are on cotrimoxazole until three months after cessation of the treatment. Cyclophosphamide is an alkylating agent which affects both B and T lymphocytes. Following the death of 16 year-old girl with JSLE due to PCP, the team reviewed the possible contributing factors, undertook a review of literature and discussed this at multi-disciplinary meetings involving the microbiology and immunology teams. This patient was found to have other risk factors for PCP – low CD4 T cells, concomitant use of corticosteroids and hypogammaglobulinaemia (IgG 3.0g/L). Although there is limited evidence that rituximab on its own increases the risk of PCP, there is emerging data that B cells may have a role in the protection against pneumocystis. Following the review, it was concluded that children on rituximab and an additional immunosuppressant (including corticosteroids) should receive prophylactic cotrimoxazole to cover PCP. Methods Retrospective audit carried out by the team to look at adherence to the new guideline regarding the use of cotrimoxazole for PCP prophylaxis in patients who have had rituximab between August 2017 and May 2019. Results P54 Table 1 Total number of patients who had rituximab 10 Number of patients who had other immunosuppressants concomitantly / recently (within previous 3 months) 7 Number of patients on rituximab monotherapy 2 Number of patients who are 6 months post-treatment 1 Number of patients with other risk factors for PCP 1 (hypogammaglobulinaemia) Number of patients who are eligible for prophylaxis, as per the guideline 8 (7 for concomitant immunosuppression and 1 for hypogammaglobulinaemia) Number of patients on cotrimoxazole 7 (87.5%) - one of the patients is on methotrexate, which is advised not to combine with cotrimoxazole We achieved 87.5% compliance in prescribing cotrimoxazole for PCP prophylaxis to all rheumatology patients receiving rituximab alongside another immunosuppressant agent; the one patient who this was not adhered to was due to potential adverse drug pharmacodynamic interaction between cotrimoxazole and methotrexate. Conclusion Although the current evidence points to increased risk of PCP in patients with inherited and iatrogenic defect of T cell function, there is emerging evidence that B cells may have a role too. Hence more work is required to determine the risk of PCP in patients on B cell targeted therapy (BCTT) and the need for prophylaxis. Conflicts of Interest The authors declare no conflicts of interest.

scholarly journals Metabolic defects in splenic B cell compartments from patients with liver cirrhosis

2020 ◽  
Vol 11 (10) ◽  
Author(s):  
Man Huang ◽  
Xiaoju Liu ◽  
Haocheng Ye ◽  
Xin Zhao ◽  
Juanjuan Zhao ◽  
...  
Keyword(s):  
Liver Cirrhosis ◽  
B Cells ◽  
B Cell ◽  
Memory B Cells ◽  
Rna Seq ◽  
Vaccine Responses ◽  
Cell Functions ◽  
Metabolic Defects ◽  
Cell Compartments ◽  
Cirrhotic Patients

Abstract Liver cirrhosis is associated with defective vaccine responses and increased infections. Dysregulated B cell compartments in cirrhotic patients have been noticed but not well characterized, especially in the spleen. Here, we comprehensively investigated B cell perturbations from the spleens and peripheral blood of cirrhotic patients. We found that liver cirrhosis significantly depleted both switched and nonswitched splenic memory B cells, which was further confirmed histologically. Bulk RNA-seq revealed significant metabolic defects as the potential mechanism for the impaired splenic B cell functions. Functionally, the splenic memory B cells from cirrhotic patients showed strong metabolic defects and reduced proliferation compared with those from healthy controls. Thus, liver cirrhosis extensively disturbs the splenic and peripheral B cell compartments, which may contribute to defective humoral immunity during liver cirrhosis.

Non-Cognate Cytotoxic T Cells Can Be Retargeted Against CD20 Positive Tumour Cells Using [Fab' × MHC Class I/Peptide] Conjugates.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2838-2838
Author(s):  
Angela D Hamblin ◽  
Ben CR King ◽  
Ruth R French ◽  
Claude H Chan ◽  
Alison L Tutt ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Mhc Class I ◽  
Peripheral Blood ◽  
Class I ◽  
B Cell Depletion ◽  
Cytokine Release ◽  
Anti Cd20

Abstract Abstract 2838 To circumvent cytotoxic T lymphocyte (CTL) tolerance of tumour-associated antigens, the concept of redirecting CTLs against non-cognate targets has developed. One way of doing this is to use bispecific antibodies comprising anti-CD3 and anti-tumour antigen moieties. Unfortunately, this is frequently associated with unacceptable toxicity due to inflammatory cytokine release. As an alternative our approach has been to use a bivalent conjugate recognising a tumour antigen (through an antibody fragment) and a defined population of CTLs (specific for a single antigenic peptide e.g. viral epitope) through peptide presented in the context of recombinant MHC class I. We have produced a conjugate consisting of an anti-human CD20 Fab' fragment joined via a chemical crosslinker (succinimidyl-4-(N-maleimidomethyl) cyclohexane-1-carboxylate) to murine MHC class I/peptide (Kbα1-α3 domains/β2microglobulin presenting the ovalbumin-derived peptide SIINFEKL; expressed bacterially as a continuous polypeptide single chain trimer after Yu et al, J Immunol 2002). Size exclusion chromatography allowed purification of conjugates with [Fab':MHC class I/peptide] ratios of 1:1 and 2:1 (F2 and F3 respectively). In vitro both constructs were able to redirect the transgenic murine CTL line OT-1 (specific for KbSIINFEKL) to lyse human CD20+ tumour cells (lymphoblastoid Daudi cell line) at effector: target ratios of 10:1. This lysis could be blocked by the addition of 100 fold excess of either anti-CD20 F(ab')2 or the Kb/SIINFEKL-specific antibody 25D1. The constructs were also able to cause in vitro proliferation of naïve OT-1 cells (but not irrelevant CD8+ T cells) in the presence of human CD20+ cells in both thymidine incorporation and CFSE dilution assays. Using a human CD20 transgenic mouse model (Ahuja et al, J Immunol 2007) we have evaluated both constructs in vivo for their ability to redirect adoptively transferred OT-1 cells to deplete B cells from the peripheral blood. A single dose of 1 nmole F3 and 2 nmole F2 caused respectively up to 95% and 85% B cell depletion at day 7. The efficacy of lower doses suggested a dose: response relationship. As a marker of toxicity, we have measured cytokine levels at 2, 8 and 24 hours following a dose of 1 nmole F3 and compared them to those seen after administration of an [anti-CD3 × anti-CD20] bispecific F(ab')2 at a dose (0.5 nmole) which produced similar day 7 peripheral blood B cell depletion: phosphate-buffered saline was given as a negative control. Maximal cytokine release was seen at 2 hours with the levels of IL-4, IL-5, KC, IL-2 and IL-10 being lower after administration of the F3 than after the bispecific F(ab')2. However, interestingly, the F3 resulted in greater IL-12 release. Overall these data suggest that [Fab' × MHC class I/peptide] constructs have the potential to redirect non-cognate CTLs to deplete CD20+ malignant B cells from the peripheral blood and that this is associated with a lower level of cytokine release than a similarly efficacious dose of an anti-CD3-containing bispecific F(ab')2. Furthermore, the ability of [Fab' × MHC class I/peptide] constructs to cause proliferation of OT-1 cells in vitro suggests it may be possible to use a single molecule to both generate a secondary cytotoxic T cell response and subsequently to retarget it, increasing the viability of the approach if adopted in the clinic. Disclosures: No relevant conflicts of interest to declare.

Sustained Depletion of B-Cells by a Humanized, Fc-Engineered Anti-CD20 Antibody, AME-133v, in Patients with Relapsed Follicular Lymphoma

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4977-4977
Author(s):  
Jennifer Wayne ◽  
Kristen N. Ganjoo ◽  
Andres Forero ◽  
Brad Pohlman ◽  
Sven de Vos ◽  
...  
Keyword(s):  
Clinical Trials ◽  
B Cells ◽  
Phase I ◽  
Follicular Lymphoma ◽  
B Cell ◽  
Cell Depletion ◽  
B Cell Depletion ◽  
Cell Counts ◽  
Evaluable Population ◽  
Anti Cd20

Abstract Abstract 4977 Sustained Depletion of B-Cells by a Humanized, Fc-Engineered Anti-CD20 Antibody, AME-133v, in Patients with Relapsed Follicular Lymphoma J Wayne,1 K Ganjoo,2 A Forero,3 B Pohlman,4 S de Vos,5 S Carpenter,6 J Wooldridge,6 S Marulappa,1 V Jain11Mentrik Biotech, LLC, Dallas, TX, 2Standford University Medical Center, Stanford, CA, 3Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL,4Cleveland Clinic Taussig Cancer Institute, Cleveland, OH, 5David Geffen School of Medicine at University of California, Los Angeles, CA, 6Eli Lilly and Company, Indianapolis, Indiana Introduction AME-133v is a humanized anti-CD20 monoclonal antibody that has a 13 to 20-fold increase in binding affinity and approximately 6-fold more potent effector function in antibody-dependent cell-mediated cytotoxicity (ADCC) compared to rituximab. Phase I/II clinical trials of AME-133v in patients with relapsed follicular lymphoma have demonstrated an overall response rate of greater than 30% with a complete response rate of 16%. The extent and duration of depletion of CD19+ B-cells in peripheral blood was used as a surrogate of therapeutic levels of AME-133v. Analysis from the Phase I/II clinical trials is presented in this report. Methods CD-19 positive B-cells in peripheral blood were measured in 77 patients with relapsed follicular lymphoma enrolled in two phase I/II clinical trials of AME-133v. These studies assessed five different doses of AME-133v (from 2 mg/m2 to 375 mg/m2). AME-133v was administered intravenously four times at weekly intervals in both trials. Blood samples were taken at multiple time points throughout the trial and a central lab measured levels of circulating CD19+ B-cells using fluorescence-activated cell sorting (FACS). Results Excluding the four patients enrolled in the 2 mg/m2 dose cohort, depletion of peripheral B-cells occurred in all patients and was sustained over time (Table 1). Baseline levels of B-cell counts ranged from 4 × 103 to 1,187 × 103 cells/μL, with an average of 102 × 103 cells/μL and a median of 60 × 103 cells/μL. Within 24 hours of the first infusion, all patients had depletion of circulating B-cells; ninety-six percent of patients had less than 10 × 103 cells/μL and two patients had less than 20 × 103 cells/μL. Interestingly, AME-133v was effective at depleting B-cells even at doses as low as 7.5 mg/m2. To assess sustainability of B-cell depletion after four doses of AME-133v, CD19+ cell counts were evaluated at nine weeks after the fourth infusion and every three months thereafter. Complete depletion of CD19+ lymphocytes was sustained for nine weeks. At five months after the last infusion of AME-133v, nearly two-thirds of patients had no detectable circulating B-cells. Sustained B-cell depletion lasted for at least eight months following the last infusion in 63% of patients. Table 1. B-cell counts for all patients in 7.5, 30, 100 and 375 mg/m2 cohorts. Percentages are cumulative Time Point Cell Count (x 103 cells/μL) 0 < 1 2 to 10 11 to 30 31 to 50 < 100 Day 1 (24 hours after last infusion) 62 % 66 % 96 % 100 % 100% 100% Day 7 (day of infusion 2) 75% 80% 95% 97% 97% 98% Day 28 (1 week after last infusion) 78 % 87% 95% 98% 98% 100% Day 84 (9 weeks after last infusion) 78% 87% 91% 96% 96% 98% Day 174 (5 months after last infusion) 60% 60% 70% 86% 93% 100% Day 264 (8 months after last infusion) 26% 26% 41% 63% 81% 89% Day 354 (11 months after last infusion) 0% 0% 15% 40% 55% 80% DEMOGRAPHIC CHARACTERISTICS (EVALUABLE POPULATION) “\f C \l 1 Demographic and Disease Characteristics on evaluable population (N=30) Conclusion The rapid and sustained effect of AME-133v on B-cell depletion, even in low-affinity FcγRIIIa patients, indicates a potentially relevant biological activity of the antibody in treating B-cell non-Hodgkin lymphoma. Notably, this depletion occurred even at very low doses of drug administration and persisted over time. This may be related to its higher affinity for CD20, increased ADCC, or both. The sustained B-cell depletion may result in prolonged clinical response and might mitigate the need for maintenance therapy. A randomized trial is being planned to compare efficacy of AME-133v vs. rituximab. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Sodium stibogluconate and CD47-SIRPα blockade overcome resistance of anti-CD20-opsonized B cells to neutrophil killing

2021 ◽  
Author(s):  
Dieke J. van Rees ◽  
Maximilian Brinkhaus ◽  
Bart Klein ◽  
Paul Verkuijlen ◽  
Anton T.J. Tool ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Tumor Cells ◽  
Target Cells ◽  
Sodium Stibogluconate ◽  
B Cell Malignancies ◽  
Lymphoma Cells ◽  
B Lymphoma ◽  
B Lymphoma Cells ◽  
Anti Cd20

Anti-CD20 antibodies, like rituximab, are broadly used to treat B cell malignancies. These antibodies can induce various effector functions, including immune cell-mediated antibody-dependent cellular cytotoxicity (ADCC). Neutrophils can induce ADCC towards solid cancer cells by trogoptosis, a cytotoxic mechanism known to be dependent on trogocytosis. However, neutrophils appear incapable of killing rituximab-opsonized B lymphoma cells. Nevertheless, neutrophils do trogocytose rituximab-opsonized B lymphoma cells, yet this only reduces CD20 surface expression, and is thought to render tumor cells therapeutically resistant to further rituximab-dependent destruction. Here, we demonstrate that resistance of B lymphoma cells towards neutrophil killing can be overcome by a combination of CD47-SIRPα checkpoint blockade and sodium stibogluconate (SSG), an anti-leishmanial drug and documented inhibitor of the tyrosine phosphatase SHP-1. SSG enhanced neutrophil-mediated ADCC of solid tumor cells, but enabled B lymphoma cell trogoptotic killing, by turning trogocytosis from a resistance-contributing mechanism into a cytotoxic anti-cancer one. The killing in the presence of SSG required both antibody opsonization of the target cells, as well as disruption of CD47-SIRPα interactions. These results provide a more detailed understanding of the role of neutrophil trogocytosis in antibody-mediated destruction of B cells and clues on how to further optimize antibody therapy of B cell malignancies.

scholarly journals Reprogramming the antigen specificity of B cells using genomeediting technologies

2018 ◽  
Author(s):  
James E. Voss ◽  
Alicia Gonzalez-Martin ◽  
Raiees Andrabi ◽  
Roberta P. Fuller ◽  
Ben Murrell ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cytidine Deaminase ◽  
Variable Region ◽  
Neutralizing Antibody ◽  
Surface Expression ◽  
Affinity Maturation ◽  
Cell Surface Expression ◽  
Human Antibody ◽  
Antigen Specificity

We have developed a method to introduce novel paratopes into the human antibody repertoire by modifying the immunoglobulin genes of mature B cells directly using genome editing technologies. We used CRISPR-Cas9 in a homology directed repair strategy, to replace the heavy chain (HC) variable region in B cell lines with that from an HIV broadly neutralizing antibody, PG9. Our strategy is designed to function in cells that have undergone VDJ recombination using any combination of variable (V), diversity (D) and joining (J) genes. The modified locus expresses PG9 HC which pairs with native light chains resulting in the cell surface expression of HIV specific B cell receptors (BCRs). Endogenous activation-induced cytidine deaminase (AID) in engineered cells allowed for Ig class switching and generated BCR variants with improved anti-HIV neutralizing activity. Thus, BCRs engineered in this way retain the genetic flexibility normally required for affinity maturation during adaptive immune responses.

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