Cell encapsulation potential of chitosan-alginate electrostatic complex in preventing natural killer and CD8⁺ cell-mediated cytotoxicity: an in vitro experimental study

Abstract

Natural killer and cytotoxic CD8+ T cells are involved in the rapid clearance of cells which express foreign antigens. Hence, these cells are crucial elements of the vertebrate immune system. However, these benefits turn problematic when they cause transplant rejection through their direct cytotoxic effects on donor organs/cells, which is attributed to the human leukocyte antigen disparity. To overcome these limitations, a strategy has been devised wherein the above effects can be minimised by shielding the cells through encapsulation. The layer-by-layer approach was employed for encapsulation using chitosan and alginate. Confocal microscopy, scanning electron microscopy confirmed the complete shielding of cells. Encapsulation did not affect cell viability as no toxicity was discerned. Calcein release assay was applied for assessing cell-mediated cytotoxicity. It was observed that the encapsulated cells underwent lesser lysis, thereby revealing the potential that this approach offers in reducing conditions such as graft failure and hypersensitivity.

Keywords:

• Cell encapsulation
• chitosan
• alginate
• natural killer cells
• cytotoxic T cells
• calcein release assay

Acknowledgements

The authors thank Mr. Ashok Kumar Sahu and Dr. Akanksha Sharma from the Advanced Instrumentation Research Facility (AIRF), Jawaharlal Nehru University, Delhi, for providing the confocal and scanning electron microscopic facilities, respectively; Mrs. Namitha Kalra and Dr. Ravi Soni for extending flow cytometry and fluorescence microscopy facilities at INMAS, DRDO, Delhi; and Dr. Rajkumar, for the fluorimetric readings.

Disclosure statement

This work is filed for patenting in the Indian Patent Office with Application Number 2159/DEL/2015.

Additional information

Funding

Vikas Chander thanks the University Grants Commission (UGC, India) for the research fellowship. The corresponding author acknowledges the Defence Research and Development Organisation (DRDO), India, for the Project Number ST/P1/2008/INM/311/1.6.