Antibodies are antigenic proteins. It is still a vaccine.
vaccine /vac·cine/ (vak´sēn) a suspension of attenuated or killed microorganisms (viruses, bacteria, or rickettsiae), or of antigenic proteins derived from them, administered for prevention, amelioration, or treatment of infectious diseases.
The confusion surrounding the definition of the word "vaccine" was used to help railroad Andrew Wakefield. He had filled out a patent for Royal Free Hospital for an injectible measles immunoglobulin treatment for persistent measles infection, which was therefore classified as a vaccine. Then Merck went after him, claiming that he was trying to compete with the MMR, even though his treatment had already been scrapped because it proved ineffective.