For 10 points, what is this kind of antibody-containing serum protein that is distinct from albumin and similar types alpha-1, alpha-2, and beta?
Its presence is indicated in the rightmost of the five regions of a serum electrophoresis gel.  If you don't have enough of it, you suffer from common variable immunodeficiency.  Prepared from pooled plasma, it's given to people at high risk for rubella, measles, or chickenpox, but is most commonly injected to develop active immunity against hepatitis A.  For 10 points, what is this kind of antibody-containing serum protein that is distinct from albumin and similar types alpha-1, alpha-2, and beta?
Its presence is indicated in the rightmost of the five regions of a serum electrophoresis gel.  
gamma globulin