ELISPOT

This article talks about how the US government is attempting to develop a new, safer vaccine against smallpox. This is part of an attempt to protect the country against the threat of bioterrorism--that is, the use of weaponized pathogens.

The article talked about how monkeys have been used to test the efficacy of the vaccine. Inoculated monkeys are exposed to the monkeypox virus, which closely resembles smallpox. The researchers then determine if the vaccine provides any protection against the virus.

Obviously, it would be unethical to test the vaccine on humans in the same fashion. (Heck, it's hard enough testing them on monkeys! How tragic.) Fortunately, the ELISPOT technique allows the immune response to be monitored ex vivo; that is, without injecting any pathogens into a human host.