Category: Cell Therapies

Categories
Cancer Cell Therapies Infectious Diseases Precision Medicine

Genetically Engineered B Cells and Their Implications on Disease Treatment

Zachary Kazaz—McMaster Integrated Science Program, Specialization in Biology 2025

Recent advancements in genome editing have facilitated major developments in both existing and new gene therapies (Hirakawa et al., 2020). The culmination of these findings became most evident on July 5th 2018, when Dr. Carl June and Professor Michel Sadelain published a seminal review article in the New England Journal of Medicine, reporting the clinical success of chimeric antigen receptor (CAR) T cell therapy against certain haematological cancers; the therapy subsequently received FDA approval for lymphoma and leukaemia treatment (June & Sadelain, 2018). T cells were modified with artificial receptors that associated the recognition of target antigens with the signalling and immunological responses of the T cell (Ellis et al., 2021). Furthermore, genome editing was successfully used to remove immune checkpoints limiting T cell functionality and improving receptor efficacy (Ellis et al., 2021). The successes of CAR T cell therapies have extended the applications of immune cell reprogramming to a population less investigated thus far — the B cell.

Adaptive immune responses are facilitated by white blood cells, or lymphocytes. There are two classes of adaptive immune response: humoral (antibody responses) and cell-mediated responses, primarily enabled by two types of lymphocytes: B-cells and T-cells, respectively (Alberts et al., 2002). Humoral adaptive immunity produces antigen-specific antibodies via B-cells that identify pathogens by binding to their expressed antigens, stimulating cell-mediated immunity by signalling T-cells, cytokines, macrophages and chemical mediators which attack and neutralize the pathogen (Johnson et al., 2018). Thus, B-cells regulate the entire adaptive immune system via general and specific mechanisms, facilitated by cytokine secretion and antigen presentation respectively (Rogers & Cannon, 2021). As a result, B-cells provide a means of modifying holistic immune responses which is a more effective immunotherapy than the sole modification of cell-mediated immunity found in current immunotherapies (e.g., T-cells).

Following the first, primary, response to a specific antigen, the responding, naive, B-cells will proliferate into a colony, differentiate into effector B-cells which produce antibodies, and following infection, will form memory B-cells which encode for and maintain the antigen-specific antibody of the pathogen encountered (Akkaya et al., 2019). This enables more rapid secondary active immune response mobilization if the same antigen exposure occurs subsequently, and can provide lifelong immune surveillance (Akkaya et al., 2019). As a result, humoral immunity facilitated by B-cells is the most capable mechanism of providing prolonged immune surveillance (Rogers & Cannon, 2021).

B-cells possess many unique characteristics that make them a promising focal point for genetic engineering in immunotherapy settings. B-cells can be easily isolated in abundance from peripheral blood, then subsequently activated, grown, and matured in culture ex-vivo (Liebig et al., 2009). It is possible to engineer these isolated B-cells to express a particular gene, mature them into effector B-cells, which produce large amounts of antibodies, and add them back to the host as a remarkably effective form of gene therapy enabling long-term immunity to disease, as seen in Figure 1 (Johnson et al., 2018). In particular, gene editing can be used to alter antigen specificity with a predetermined antibody by means that permit access to all functions of the B-cell during every stage of its life cycle (Rogers & Cannon, 2021).

Figure 1. Diagram displaying the procedure of B-cell immunotherapy in patients using host donor cells (Traxinger, 2019).

By altering the variations of modified antigen-specificity, the response of B-cells to target antigens, their subsequent production of antibodies, expansion, and formation of long-term immunity, we can introduce and evolve long-term antibody specificity to reprogram B-cells that will continue to adapt to their associated pathogens (Rogers & Cannon, 2021). This is particularly relevant, as a majority of current literature on B-cell engineering focuses on producing HIV-specific B-cells (Rogers & Cannon, 2021). The prolonged antibody expression of B-cell therapy can be used to suppress chronic viral infections such as HIV. More importantly, highly mutagenic viruses, such as HIV, are capable of evading antigen-specific antibody responses, and edited B-cells can adapt to these changes, enabling B-cells to keep pace with viral mutations (Ouyang et al., 2017). This is not possible with current therapies that use fixed antigen-specificities.

The broad array of B-cell functions open many potential immune cell gene therapies. For example, the ability of antibody production in effector B-cells allows them to be used as a long-term source for the production of therapeutic proteins in-vivo, such as bnAbs and factor IX to combat hepatitis C virus and HIV (Kuhlmann et al., 2018). Also, it is possible to create these “cellular factories” using stem cells or editing B-cells ex-vivo which can be altered with a variety of methods such as CRISPR/CAS9 and viral vectors which transport the modified gene to loci of interest (Luo et al., 2020). Moreover, naive B-cells can be modified to present antigens and suppress or prevent immune responses to particular antigens, which can be used to combat autoimmune diseases (Scott, 2011).

Interestingly, B-cell engineering offers potential as an improved means of vaccination. In May of 2019, Howell et al. published findings in Scientific Immunology showing that B-cells edited to express antibodies countering respiratory syncytial virus (RSV) produced highly effective and long-lasting protection from RSV infection in mice (Moffett et al., 2019). Such findings convey that sterilizing immunity to pathogens can be accomplished in a more effective manner than current vaccination methods are able to induce or sustain.

Though great strides have been made, moving forwards, many further steps are needed for B-cell therapies to become viable in the future. Up to now, studies have used mice, however, larger animal models more related to human immunology are required to gain more practical insights. Further, studies must be conducted long-term to assess the durability of antibody production and memory in edited B-cells (Rogers & Cannon, 2021). Additionally, novel methods of delivering B-cell therapies to patients must be developed to make B-cells commercially viable and accessible on a broad scale. Engineered B-cells should be manufactured en masse from universally matching batches of unrelated donor cells (i.e. allogeneic) instead of an exclusive therapy manfactured from a single sample of patient-related donor cells (i.e. autologous). Current studies propose using B-cells from induced pluripotent stem cells, which is currently being investigated for use in CAR T cells (French et al., 2015).

Today, genetically engineered B-cells present a great capacity as a highly effective immunotherapy for particular autoimmune disorders, cancers, chronic infectious diseases, and pathogens. Further experimentation is required to progress B-cell gene therapy to human trials, however, in the near future, we are likely to see B-cells accompany CAR T-cells as a novel immune cell therapy. In the far future, the broad and holistic applications of engineered B-cells may become the basis of future immunotherapies, vaccines, and disease treatments.

References

  1. Akkaya M, Kwak K, Pierce SK. B cell memory: Building two walls of protection against pathogens. Nature Reviews Immunology [Internet]. 2019Dec13 [cited 2022Nov29];20(4):229–38. Available from: https://www.nature.com/articles/s41577-019-0244-2
  2. Alberts B, Johnson A, Lewis J, Raff M, Roberts K, Walter P. Chapter 24: The Adaptive Immune System. In: Molecular Biology of the Cell [Internet]. 4th ed. New York, NY: Garland Science; 2002 [cited 2022Nov28]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK21070/
  3. Ellis GI, Sheppard NC, Riley JL. Genetic engineering of T cells for immunotherapy. Nature Reviews Genetics. 2021Feb18;22(7):427–47. French A, Yang C-T, Taylor S, Watt SM, Carpenter L. Human induced pluripotent stem cell-derived B lymphocytes express SIGM and can be generated via a hemogenic endothelium intermediate. Stem Cells and Development [Internet]. 2015May [cited 2022Dec8];24(9):1082–95. Available from: https://www.liebertpub.com/doi/10.1089/scd.2014.0318
  4. Hirakawa MP, Krishnakumar R, Timlin JA, Carney JP, Butler KS. Gene editing and CRISPR in the clinic: Current and future perspectives. Bioscience Reports [Internet]. 2020Apr9 [cited 2022Nov26];40(4). Available from: https://portlandpress.com/bioscirep/article/40/4/BSR20200127/222452/Gene-editing-and-C RISPR-in-the-clinic-current-and
  5. Johnson MJ, Laoharawee K, Lahr WS, Webber BR, Moriarity BS. Engineering of primary human B cells with CRISPR/Cas9 targeted nuclease. Scientific Reports [Internet]. 2018Aug14 [cited 2022Nov29];8(1). Available from: https://www.nature.com/articles/s41598-018-30358-0
  6. June CH, Sadelain M. Chimeric antigen receptor therapy. New England Journal of Medicine. 2018Jul5;379(1):64–73. Kuhlmann A-S, Haworth KG, Barber-Axthelm IM, Ironside C, Giese MA, Peterson CW, et al.
  7. Long-term persistence of Anti-HIV broadly neutralizing antibody-secreting hematopoietic cells in humanized mice. Molecular Therapy [Internet]. 2018Sep17 [cited 2022Dec6];27(1):164–77. Available from: https://www.sciencedirect.com/science/article/pii/S1525001618304581
  8. Liebig TM, Fiedler A, Zoghi S, Shimabukuro-Vornhagen A, von Bergwelt-Baildon MS. Generation of human CD40-activated B cells. Journal of Visualized Experiments [Internet]. 2009Oct16 [cited 2022Dec4];(32). Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3164064/
  9. Luo B, Zhan Y, Luo M, Dong H, Liu J, Lin Y, et al. Engineering of α-PD-1 antibody-expressing long-lived plasma cells by CRISPR/Cas9-mediated targeted gene integration. Cell Death and Disease [Internet]. 2020Nov12 [cited 2022Dec6];11(973). Available from: https://www.nature.com/articles/s41419-020-03187-1
  10. Moffett HF, Harms CK, Fitzpatrick KS, Tooley MR, Boonyaratanakornkit J, Taylor JJ. B cells engineered to express pathogen-specific antibodies protect against infection. Science Immunology [Internet]. 2019May17 [cited 2022Dec4];4(35). Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6913193/
  11. Ouyang Y, Yin Q, Li W, Li Z, Kong D, Wu Y, et al. Escape from humoral immunity is associated with treatment failure in HIV-1-infected patients receiving long-term antiretroviral therapy. Scientific Reports [Internet]. 2017Jul24 [cited 2022Dec4];7(1). Available from: https://www.nature.com/articles/s41598-017-05594-5
  12. Rogers GL, Cannon PM. Genome edited B cells: A new frontier in immune cell therapies. Molecular Therapy [Internet]. 2021Nov3 [cited 2022Nov28];29(11):3192–204. Available from: https://www.sciencedirect.com/science/article/pii/S1525001621004743
  13. Scott DW. Gene Therapy for Immunologic Tolerance: Using Bone Marrow-Derived Cells to Treat Autoimmunity and Hemophilia. Current Stem Cell Research & Therapy [Internet]. 2011Mar1 [cited 2022Dec4];6(1):38–43. Available from: https://www.ingentaconnect.com/content/ben/cscr/2011/00000006/00000001/art00006
  14. Traxinger B. Engineering B cells to bypass vaccines [Internet]. Fred Hutch Cancer Center. Taylor Lab, Vaccine and Infectious Disease Division; 2019 [cited 2022Dec14]. Available from: https://www.fredhutch.org/en/news/spotlight/2019/07/moffett_vidd_sciimmuno.html
Categories
Cell Therapies

Cell Therapies for Cancer Treatment: How it Works

Nicol Vaizman—McMaster University Molecular Biology and Genetics 2023

An exciting new area of research in cancer biology has generated a great deal of attention as traditional treatments such as chemotherapy, radiation and surgery have not yet fully eliminated the reappearance of cancerous cells and resistance to drugs. Presently, the scientific field of regenerative medicine is advancing and so, the use of cell therapy has become a backbone in the development of cancer treatments. By doing so, scientists have even considered defining cancer as a stem cell disorder rather than that of abnormal cells dividing uncontrollably. Stem cells are unique in their ability to divide into specialized cells and the stem-cell origin of cancerous cells is due to the acquisition of damaged stem cells. 

SOURCE: The Canadian Cancer Society

Cell therapies are designed in such a way that the immune system of a patient is improved and thus, able to fight cancer on its own1. The immune system plays a central role in the body as it recognizes, targets and eliminates any unfamiliar substances to protect the body from disease. However, our own cells are capable of becoming cancerous when gene mutations develop thus, the immune system does not always recognize that they are a threat and need to be destroyed as they contain our own DNA which is recognized as natural and the body’s own tissues2. The spread of cancerous cells into the bone marrow weakens the immune system as less white blood cells are produced to fight infection3.

T cells are a specific type of white blood cell that are essential to the regulatory processes that take place within the body to counteract infections4. These specialized cells have receptors which allow them to attach to surface proteins found on foreign cells called antigens5. The relationship between immune receptors and antigens are analogous to a lock and key because just as every lock can only be opened with a correctly sized key, each foreign antigen has a unique receptor that is able to bind to it. These antigens are also present on cancerous cells but if the immune cells do not have the correct receptors for them, they cannot attach to the antigens and help destroy the cancer cells. This comprehensive knowledge is what led to the discovery of a specific type of immunotherapy as it harnesses the powers of the immune system to attack tumors and ultimately, cure cancer. 

Chimeric antigen receptor (CAR) T-cell therapy is the new promising type of immunotherapy as T cells are genetically altered to better find antigens on the surface of cancerous cells and destroy them. Through a procedure called leukapheresis, T cells are removed and separated from the patient’s bloodstream through an IV and then sent to a lab6. Chimeric antigen receptors are then engineered into the T cells through an inactive virus in order to make them stick to cancer cells. When these new cells multiply, they are ready to be infused back into the patient’s bloodstream and can now precisely attack the tumor by releasing toxins7. As different types of cancers have various antigens, CAR T-cells are specific to the disease that the patient is fighting. By doing so, this cell therapy can eradicate all cancerous cells and remain in the body to ensure long-term remission for the patient. 

CAR T-cell therapy
SOURCE: Cleveland Clinic

The delivery of anti-cancer agents such as CAR T-cells has had large success rates for cancers such as leukemia and lymphoma, as a 30-40% success rate for lasting remission with no additional treatment has been noted8. As larger sample sizes and longer time periods of remission are analyzed, this type of cell therapy is being further developed to treat solid tumors such as those found in breast and lung cancer. Therapeutic systems are constantly being designed in the overall aim to improve the outcome in the fight against cancer. 

References

1 Cancer Treatments: The Newest Tools Doctors Are Using To Fight This Disease [Internet]. WebMD. WebMD; 2020 [cited 2021Feb19]. Available from: https://www.webmd.com/cancer/cancer-new-research-treatment

2 The immune system – Canadian Cancer Society [Internet]. http://www.cancer.ca. [cited 2021Feb19]. Available from: https://www.cancer.ca/en/cancer-information/cancer-101/what-is-cancer/the-immune-system/

3 The immune system – Canadian Cancer Society [Internet]. http://www.cancer.ca. [cited 2021Feb19]. Available from: https://www.cancer.ca/en/cancer-information/cancer-101/what-is-cancer/the-immune-system/

4 CAR T-cell therapy [Internet]. Cleveland Clinic. [cited 2021Feb19]. Available from: https://my.clevelandclinic.org/health/treatments/17726-car-t-cell-therapy

5 CAR T-cell therapy [Internet]. Cleveland Clinic. [cited 2021Feb19]. Available from: https://my.clevelandclinic.org/health/treatments/17726-car-t-cell-therapy 

6 LaRussaA. Chimeric Antigen Receptor (CAR) T-Cell Therapy [Internet]. Chimeric Antigen Receptor (CAR) T-Cell Therapy | Leukemia and Lymphoma Society. 2015 [cited 2021Feb19]. Available from: https://www.lls.org/treatment/types-of-treatment/immunotherapy/chimeric-antigen-receptor-car-t-cell-therapy

7 Watson S. CAR T-Cell Therapy: What You Should Know Today [Internet]. WebMD. WebMD; 2021 [cited 2021Feb19]. Available from: https://www.webmd.com/cancer/lymphoma/features/car-t-gene-therapy-risks-benefits#

8 Bartosch J. Three years after CAR T-cell therapy for lymphoma, patient still cancer-free [Internet]. UChicago Medicine. UChicago Medicine; 2019 [cited 2021Apr2]. Available from: https://www.uchicagomedicine.org/forefront/cancer-articles/a-walking-miracle-car-t-cell-therapy