New study supports RH5 vaccine trials in malaria-endemic regions
A new study conducted by the NIH and the Draper group has generated encouraging data that supports the continued development of RH5 based vaccines in malaria endemic regions. A former lead blood-stage malaria candidate, AMA1, struggled to gain traction in human clinical trials in malaria endemic regions partly due to inteference between existing antimalarial antibodies in the blood interfering with the activity of vaccine-induced AMA1 antibodies. In this new study, Wilcox et al. show that the existing RH5 response in malaria endemic regions is low compared to responses generated by RH5 vaccination. In addition existing anti-malaria antibodies add to the malaria blocking activity of RH5 vaccine induced polyclonal antibodies.
These results suggest that vaccination with RH5 in malaria endemic regions will not suffer from interference with existing immunity improving the chances of success.
Paper Highlights
- RH5 IgG titers induced by infection are lower than those induced by RH5 vaccination
- Infection- and vaccine-induced RH5 IgGs have different specificity and avidity
- Infection- and vaccine-induced RH5 IgGs interact differently with RH5 mAbs
- Infection-induced IgGs generally do not reduce the activity of vaccine-induced IgGs
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