Most vaccines are required to be stored at low temperatures to ensure that they remain safe and effective when administered to patients. The temperature-controlled supply chain for vaccines is known as the cold chain. The cold chain ensures that vaccines are refrigerated from production until they are administered to patients. Unfortunately, the cold chain may not be accessible to some parts of the world without reliable sources of electricity. For this reason, it may be difficult to vaccinate people living in these remote areas. Vaccines that bypass cold chain logistics are desirable to help increase vaccinations and to decrease costs.
Dr. David Lo and his colleagues at UCR have developed a new vaccine adjuvant that is composed of engineered cross-linked polymeric flagellin. This new adjuvant stabilizes vaccines so that it may bypass the cold chain and may potentially increase vaccination rates in remote areas without a reliable source of electricity.
Another aspect of this flagellin adjuvant is that it may induce a T helper independent immune response. This immune response may be desirable in patients with T cell immunodeficiency disorders.
Fig. 1 is a schematic that shows disulfide bonds between neighboring flagellin filaments. The covalently stabilized flagellar filament provides additional immune efficacy through the stabilization of its polymeric filament structure and this contributes to the long-term storage of a vaccine absent the cold chain
Fig. 2 shows the long term temperature stability of the adjuvant in solution. Less than 50% of the engineered adjuvant was degraded after being heated to 42°C for 7 days.
This new adjuvant will be more cost effective and the following patients may benefit from it: