Or: just when you thought Ebola was going to get you – tobacco to the rescue!
My second-favourite (hey: I work on this stuff too!) group of plant-based vaccine producers have just got a paper into Proc Natl Acad Sci Sci USA which describes the successful testing in animals of a candidate Ebola virus envelope glycoprotein (GP) vaccine as a fusion partner with an Ebola GP-binding monoclonal antibody.
Waranyoo Phoolcharoen and co-workers, from the Arntzen-Mason lab in the Biodesign Institute at Arizona State University, describe the following results:
Ebola hemorrhagic fever is an acute and often deadly disease caused by Ebola virus (EBOV). The possible intentional use of this virus against human populations has led to design of vaccines that could be incorporated into a national stockpile for biological threat reduction. We have evaluated the immunogenicity and efficacy of an EBOV vaccine candidate in which the viral surface glycoprotein is biomanufactured as a fusion to a monoclonal antibody that recognizes an epitope in glycoprotein, resulting in the production of Ebola immune complexes (EICs). Although antigen– antibody immune complexes are known to be efficiently processed and presented to immune effector cells, we found that codelivery of the EIC with Toll-like receptor agonists elicited a more robust antibody response in mice than did EIC alone. Among the compounds tested, polyinosinic:polycytidylic acid (PIC, a Toll-like receptor 3 agonist) was highly effective as an adjuvant agent. After vaccinating mice with EIC plus PIC, 80% of the animals were protected against a lethal challenge with live EBOV (30,000 LD50 of mouse adapted virus). Surviving animals showed a mixed Th1/Th2 response to the antigen, suggesting this may be important for protection. Survival after vaccination with EIC plus PIC was statis- tically equivalent to that achieved with an alternative viral vector vaccine candidate reported in the literature. Because nonreplicating subunit vaccines offer the possibility of formulation for cost-effective, long-term storage in biothreat reduction repositories, EIC is an attractive option for public health defense measures.
And while this is a VERY worthwhile result, and especially in view of the fact that plants were used to make a vaccine, there it is again: “biothreat” and “public health defense”. Like US citizens are more likely to die than people in Uganda and the DRC.
Ah, well: if we had a Department of Homeland Security, we’d apply to them for money too…B-)