

Antibodies isolated from the blood of human survivors of the avian flu offered varying degrees ofprotection to mice infected by the virus. Two monoclonal antibodies protected against two clades (roughly, "lineages"), while two others protected against only one.

The research, published in PLoS Medicine, noted that a crude form of this tactic – using antibodies from survivors through plasma transfers – halved the death rate during the

1918/9 Spanish flu epidemic. Mice received protection if given the antibody either one day before, or one to three days after viral infection.

The researchers end with a note of caution:

Before passive immunotherapy can help to halt an H5N1 pandemic, they warn, the monoclonal antibodies will have to be tested to see whether they can neutralize not only all the currently circulating H5N1 viruses but also any emerging pandemic versions, which might be antigenically distinct.

The virus has yet to mutate so that it can be transmitted through mere human contact, which is why the original fears never manifested. That possibility does still exist, so researchers want to be prepared.

Blood of Bird Flu Victims Offers Treatment [Reuters]