Detection of Anti-EPO antibody in sera of different semi-immune mice strains and control at different dilution. Sera was taken from blood harvested at minimum Hb (i.e. maximum Hb reduction) and screened for anti-EPO antibody by immunodot blot. The above data are representative data for each semi-immune mice strain. Number of mice used is two per strain. Direction of arrows indicate extent of serum dilution by a factor of 2. Upper panel (a) shows immuno dot blot for Balb/c; panel (b) immediately below (that of Balb/c) is the immuno dot blot for B6 and CBA while the third lowest panel (c) is the immuno dot blot for NZW and lower panel (d) is the immuno dot blot for uninfected control mice.