Because survivors of an Ebola infection would typically have produced effective antibodies against the virus (otherwise they wouldn't have survived), transfusions of their blood into a newly infected individual may help that person survive the often fatal disease. (scientificamerican.com)
A more effective antibody cocktail could induce a stronger immune response, require a smaller dose, or fight the other species of Ebola as well. (scientificamerican.com)
Generally, as B cells divide in response to a pathogen like HIV, genes that produce infection - fighting antibodies mutate, and descendant cells producing the most effective antibodies predominate. (sciencedaily.com)