The use of CpG adjuvants, bio-degradable microparticles, and microneedle technology for the design of novel single-dose vaccines

Vaccines are important in protecting our bodies against potentially deadly infectious diseases. The vaccines developed in the past 200 years have clearly had a great impact on human health by preventing many infectious diseases and eradicating others, such as smallpox. Despite this success, strategies for developing new and better vaccines are urgently needed. Current vaccine technologies are still inadequate to counter persistent infectious disease threats like human immunodeficiency virus (HIV), tuberculosis, and malaria. This is partly due to the limited ability of our body to mount a robust immune response to these vaccines, particularly for immuno-compromised individuals such as children, elders, and individuals on immunosuppressive treatments such as post-transplant patients or patients with autoimmune diseases. Further, during epidemics, vaccine production capacity is often limited. Dr. Jacqueline Lai will be developing/optimizing strategies that will deliver safer, more stable and effective vaccines painlessly through the skin. Dr. Lai will be exploring the use of novel vaccine formulations and delivery technologies. The laboratory in which she will train has previously shown that a DNA adjuvant – a chemical that can modulate the response to a vaccine – enhances vaccination responses when rubbed onto the skin at the time of vaccination. The use of adjuvants may increase the efficacy of small vaccine doses, resulting in the immunization of more individuals with existing vaccine production capacity. As part of her research, she will be developing new DNA adjuvant formulations and administration strategies to explore the possibility of further enhancing vaccine responses. The second part of Dr. Lai's research involves the evaluation of new vaccine delivery technologies. As the skin serves to protect us from the environment, the outer-most layer of the skin forms a tight barrier that prevents the penetration of most substances, including DNA adjuvants. To circumvent the limited penetration of adjuvants and vaccines through the skin, she will test new hollow microneedles, designed by collaborating material engineers, which allow for the painless delivery of vaccines directly into the skin. In addition, she will evaluate vaccines encapsulated in biodegradable materials to increase the stability and efficacy of the vaccine formulations and to obviate the need for refrigeration of the vaccine during distribution.