I believe that antibodies can be harvested from the sera of infected
individuals, concentrated and then administered to victims to fight
their infection. The source/host must be a survivor/carrier of the
virus (hence the search for the original host) which would have a high titer
antibodies to the agent in its blood. As an aside I think
Dustin Hoffman did all that he did within what I believe was a single
day and in real life I doubt if this could ever happen. Now I know what
it means when they say Be All That You Can be ....in the Arm..eeee.
This is not a likely scenario for a viral infection like AIDS which
destroys the very cells responsible for immunity although studies are
underway of long term survivors to see if there is such a possibility.