Research press release


Scientific Reports

Immunology: An oral Ebola vaccine for chimpanzees



今回、Peter Walshの研究チームは、10頭の飼育チンパンジーを用いてエボラウイルスに対するワクチンfilorab1の試験を行った。そのうちの6頭については、鎮静状態でウイルスの経口投与が行われ、残りの4頭には筋肉内注射でワクチン投与を行った。そして、投与後最長28日間にわたって、エボラウイルスに対する抗体の血中濃度の測定が続けられた。この試験では、経口ワクチンを投与されたチンパンジーのエボラウイルスに対する抗体のレベルが上昇し、その上昇率が筋肉内注射でワクチンを投与されたチンパンジーの場合と非常によく似ていたことが明らかになった。しかし、今回の研究では、ワクチン接種後のチンパンジーをエボラウイルスにチャレンジ感染させておらず、経口送達の防御効果を断定するにはさらなる研究が必要となっている。


An oral vaccine that may protect chimpanzees against the Ebola virus is presented in an initial study in Scientific Reports this week. The authors suggest that oral vaccination may hold promise as a safe and efficient way to protect endangered species against pathogenic threats.

Approximately one third of the world’s gorillas have been killed by Ebola and although a number of disease threats to apes are preventable using vaccines, traditional delivery using darts is challenging for use on animals that live at low density in thick, tropical forests.

Peter Walsh and colleagues conducted a trial using the vaccine filorab1 against the Ebola virus in ten chimpanzees in captivity. Six of the chimpanzees received the vaccine orally under sedation, while the other four received the vaccine via an intramuscular injection. Levels of antibodies in the blood against the Ebola virus were then monitored up to 28 days after vaccination. The authors found that levels of antibodies against the Ebola virus in the orally vaccinated chimpanzees rose during the trial, with rates of increase very similar to those seen in the chimpanzees that had received the vaccine via injection. However, none of the chimpanzees were challenged with Ebola after vaccination and future studies to further establish the protective effect of oral delivery are needed.

The authors argue that the immune response produced from a single dose of the vaccine, delivered orally, may be an advantage in the field vaccination of wild apes that are difficult to locate in dense forest. They note that field trials involving wild apes will be needed and further work on oral-bait prototypes and to stabilize the vaccine against heat for viability under hot forest conditions will be required.

doi: 10.1038/srep43339


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