Immunisation with chitosan hydrogel generates CD8+ memory T cells protective against tumour challenge

Abstract

Vaccination is used in the prevention of disease around the world. Through activation of T and B cells, and subsequent generation of memory cells, long lasting protection against disease is given. The majority of vaccines in use today exert their protective effect through generation of an antibody mediated response. It has been demonstrated that CD8+ T cells are important in protection against many diseases, including HIV and cancer. Modern vaccines able to generate an effective CD8+ memory T cell response may provide protection against these diseases. In this research, the sustained release vaccine vehicle chitosan hydrogel was assessed in its ability to generate an effective population of CD8+ memory T cells. It was hypothesised that vaccination of mice would generate a population of CD8+ memory T cells that were functional and protective against tumour challenge. Using flow cytometry, CD8+ memory T cells were identified in peripheral and gut associated lymphoid tissues of vaccinated mice. Furthermore, vaccination with chitosan hydrogel provided protection against both subcutaneous tumour challenge and in an orthotopic mouse model of colorectal cancer. Chitosan hydrogel represents a novel method of vaccine delivery. While it may be more suited towards vaccination against cancer, its ability to generate a cytotoxic immune response mediated by CD8+ T cells may be invaluable against some viral and bacterial infections with no current and effective prophylactic treatment. Thus, chitosan hydrogel is another step in modern vaccine delivery systems towards protection against a broader range of diseases and further research towards its efficacy in further tumour and infection disease models is warranted.