DELIVERY OF MONOCLONAL ANTIBODIES FROM MICROENCAPSULATED CELLS

The use of monoclonal antibodies (mabs) is a promising therapeutic approach for the prophylaxis and treatment of a wide range of illnesses, including cancer, autoimmune, and infectious disorders. They currently rank among the most widely used drugs in the pharmaceutical sector. The area of medicine where mabs are most extensively employed is oncology. Unfortunately, the complicated and costly nature of mab design, mab secretion, and purification are prohibitive and pose a hurdle to product development and pre-clinical modification, which is a significant obstacle to the use of mab therapy in clinical practice. Additionally, parenteral mab administration also poses clinical difficulties. Patients experience mild-to-moderate injection site and infusion-related responses, despite mab therapy having a low overall reactogenicity. Here, we proposed that mabs might be efficiently given by allogeneic cells that produce mabs and are encapsulated to increase cell viability and safeguard against host immunological reactions. Various illnesses, such as diabetes mellitus, anemia, cancer, and neurodegenerative disease, have been successfully treated in animal models and people through the delivery of therapeutic drugs by microencapsulated single-cell populations. A single injection of microcapsules is anticipated to be effective since the microcapsules can be tailored to last for the duration necessary for the treatment by altering the concentration of alginate and the cross-linking of alginate with PLL. While preventing immune cells from attacking the enclosed cells, the biocompatible membrane permits a bidirectional flow of nutrients, oxygen, and waste products. When a slow, continuous mab release over a lengthy period of time is necessary, cell encapsulation-aided mab delivery is preferable to bolus mab injection. Therefore, in this pre-clinical model, we investigated the feasibility of mab administration utilizing an enclosed cell culture that expresses mab. Until now, transformed hybridoma cells have been used to produce and secrete mabs. The novelty of this study is the use of non-professional immune cells, such as murine G8 myoblasts and human HEK293 (human embryonic kidney cells) cells, to secrete mabs. These cells were transfected with plasmids that encode the heavy and light chains of human IgG specific for antigens relevant in treating cancer and COVID-19 and then enclosed in alginate microcapsules. Afterward, immunocompetent (C57/BL6J) mice were intraperitoneally implanted with the microcapsules, and changes in the level of circulating mab were evaluated. Western blotting, ELISA, and microscopy were used to characterize the mab both in vitro and ex vivo. Co-transfected G8 cells secreted intact IgG at sustained levels similar to transfected HEK293 cells. Partial characterization of the secreted mab was performed. Mice implanted with 4 microcapsules containing G8 cells secreting mab induced the detection of blood mab for 40 days. This study shows the feasibility of cell microencapsulation for the systemic delivery of intact mab. This method has potential significant therapeutic applications that call for further investigation

DELIVERY OF MONOCLONAL ANTIBODIES FROM MICROENCAPSULATED CELLS

The use of monoclonal antibodies (mabs) is a promising therapeutic approach for the prophylaxis and treatment of a wide range of illnesses, including cancer, autoimmune, and infectious disorders. They currently rank among the most widely used drugs in the pharmaceutical sector. The area of medicine where mabs are most extensively employed is oncology. Unfortunately, the complicated and costly nature of mab design, mab secretion, and purification are prohibitive and pose a hurdle to product development and pre-clinical modification, which is a significant obstacle to the use of mab therapy in clinical practice. Additionally, parenteral mab administration also poses clinical difficulties. Patients experience mild-to-moderate injection site and infusion-related responses, despite mab therapy having a low overall reactogenicity. Here, we proposed that mabs might be efficiently given by allogeneic cells that produce mabs and are encapsulated to increase cell viability and safeguard against host immunological reactions. Various illnesses, such as diabetes mellitus, anemia, cancer, and neurodegenerative disease, have been successfully treated in animal models and people through the delivery of therapeutic drugs by microencapsulated single-cell populations. A single injection of microcapsules is anticipated to be effective since the microcapsules can be tailored to last for the duration necessary for the treatment by altering the concentration of alginate and the cross-linking of alginate with PLL. While preventing immune cells from attacking the enclosed cells, the biocompatible membrane permits a bidirectional flow of nutrients, oxygen, and waste products. When a slow, continuous mab release over a lengthy period of time is necessary, cell encapsulation-aided mab delivery is preferable to bolus mab injection. Therefore, in this pre-clinical model, we investigated the feasibility of mab administration utilizing an enclosed cell culture that expresses mab. Until now, transformed hybridoma cells have been used to produce and secrete mabs. The novelty of this study is the use of non-professional immune cells, such as murine G8 myoblasts and human HEK293 (human embryonic kidney cells) cells, to secrete mabs. These cells were transfected with plasmids that encode the heavy and light chains of human IgG specific for antigens relevant in treating cancer and COVID-19 and then enclosed in alginate microcapsules. Afterward, immunocompetent (C57/BL6J) mice were intraperitoneally implanted with the microcapsules, and changes in the level of circulating mab were evaluated. Western blotting, ELISA, and microscopy were used to characterize the mab both in vitro and ex vivo. Co-transfected G8 cells secreted intact IgG at sustained levels similar to transfected HEK293 cells. Partial characterization of the secreted mab was performed. Mice implanted with microcapsules containing G8 cells secreting mab induced the detection of blood mab for 40 days. This study shows the feasibility of cell microencapsulation for the systemic delivery of intact mab. This method has potential significant therapeutic applications that call for further investigation

Cell Encapsulation Within Alginate Microcapsules: Immunological Challenges and Outlook

Cell encapsulation is a bioengineering technology that provides live allogeneic or xenogeneic cells packaged in a semipermeable immune-isolating membrane for therapeutic applications. The concept of cell encapsulation was first proposed almost nine decades ago, however, and despite its potential, the technology has yet to deliver its promise. The few clinical trials based on cell encapsulation have not led to any licensed therapies. Progress in the field has been slow, in part due to the complexity of the technology, but also because of the difficulties encountered when trying to prevent the immune responses generated by the various microcapsule components, namely the polymer, the encapsulated cells, the therapeutic transgenes and the DNA vectors used to genetically engineer encapsulated cells. While the immune responses induced by polymers such as alginate can be minimized using highly purified materials, the need to cope with the immunogenicity of encapsulated cells is increasingly seen as key in preventing the immune rejection of microcapsules. The encapsulated cells are recognized by the host immune cells through a bidirectional exchange of immune mediators, which induce both the adaptive and innate immune responses against the engrafted capsules. The potential strategies to cope with the immunogenicity of encapsulated cells include the selective diffusion restriction of immune mediators through capsule pores and more recently inclusion in microcapsules of immune modulators such as CXCL12. Combining these strategies with the use of well-characterized cell lines harboring the immunomodulatory properties of stem cells should encourage the incorporation of cell encapsulation technology in state-of-the-art drug development

Sustained Delivery of a Monoclonal Antibody against SARS-CoV-2 by Microencapsulated Cells: A Proof-of-Concept Study

Background: Monoclonal antibody (mAb) therapy is a promising antiviral intervention for Coronovirus disease (COVID-19) with a potential for both treatment and prophylaxis. However, a major barrier to implementing mAb therapies in clinical practice is the intricate nature of mAb preparation and delivery. Therefore, here, in a pre-clinical model, we explored the possibility of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mAb delivery using a mAb-expressing encapsulated cell system. Methods: Murine G-8 myoblasts were transfected with plasmids coding for the heavy and light chains of CR3022, a well-characterized SARS-CoV-2 mAb that targets the Spike receptor binding domain (RBD), and then encapsulated into alginate microcapsules. The microcapsules were then intraperitoneally implanted into immunocompetent (C57/BL6J) mice and changes in circulating CR3022 titres were assessed. The in vitro and ex vivo characterization of the mAb was performed using western blotting, RBD ELISA, and microscopy. Results: Transfected G-8 myoblasts expressed intact CR3022 IgG at levels comparable to transfected HEK-293 cells. Cell encapsulation yielded microcapsules harbouring approximately 1000 cells/capsule and sustainably secreting CR3022 mAb. Subsequent peritoneal G-8 microcapsule implantation into mice resulted in a gradual increase of CR3022 concentration in blood, which by day 7 peaked at 1923 [1656–2190] ng/mL and then gradually decreased ~4-fold by day 40 post-implantation. Concurrently, we detected an increase in mouse anti-CR3022 IgG titers, while microcapsules recovered by day 40 post-implantation showed a reduced per-microcapsule mAb production. Summary: We demonstrate here that cell microencapsulation is a viable approach to systemic delivery of intact SARS-CoV-2 mAb, with potential therapeutic applications that warrant further exploration

HIGH SARS-COV-2 SEROPREVALENCE IN KARAGANDA, KAZAKHSTAN BEFORE THE LAUNCH OF COVID-19 VACCINATION

COVID-19 exposure in Central Asia appears underestimated and SARS-CoV-2 seroprevalence data are urgently needed to inform ongoing vaccination efforts and other strategies to mitigate the regional pandemic. Here, in a pilot serologic study we assessed the prevalence of SARS-CoV-2 antibody-mediated immunity in a multi-ethnic cohort of public university employees in Karaganda, Kazakhstan. Asymptomatic subjects (n = 100) were recruited prior to their first COVID-19 vaccination. Questionnaires were administered to capture a range of demographic and clinical characteristics. Nasopharyngeal swabs were collected for SARS-CoV-2 RT-qPCR testing. Serological assays were performed to detect spike (S)- reactive IgG and IgA and to assess virus neutralization. Pre-pandemic samples were used to validate the assay positivity thresholds. S-IgG and -IgA seropositivity rates among SARSCoV- 2 PCR-negative participants (n = 100) were 42% (95% CI [32.2–52.3]) and 59% (95% CI [48.8–69.0]), respectively, and 64% (95% CI [53.4–73.1]) of the cohort tested positive for at least one of the antibodies. S-IgG titres correlated with virus neutralization activity, detectable in 49% of the tested subset with prior COVID-19 history. Serologically confirmed history of COVID-19 was associated with Kazakh ethnicity, but not with other ethnic minorities present in the cohort, and self-reported history of respiratory illness since March 2020. Overall, SARS-CoV-2 exposure in this cohort was ~15-fold higher compared to the reported all-time national and regional COVID-19 prevalence, consistent with recent studies of excess infection and death in Kazakhstan. Continuous serological surveillance provides important insights into COVID-19 transmission dynamics and may be used to better inform the regional public health response