Quantitation of diphtheria and tetanus antibodies by reversed rocket immunoelectrophoresis

A reversed rocket immunoelectrophoresis technique, applying serum samples to antigen-containing gel, is described for quantitation of human antibodies to diphtheria and tetanus. Lowering of the pH of the buffer from 8.6 to 5.2 increased the height of the rockets, but also resulted in more non-specific precipitation. This smudging could be removed by dextran sulphate precipitation of the sera, a necessity when quantitating sera with small concentrations of anti-bodies. The merits of this method are discussed in relation to other in vitro as well as in vivo methods. The method was found to be reproducible, rapid, cheap and sensitive, and to require small samples of serum.