Rates of release of subcutaneously injected antigens in the rat. Comparison of an aqueous preparation with two alum-precipated preparations

Release of antigen E-125 I from the site of subcutaneous injection in male rats was delayed significantly when either of two alum-precipitated preparations containing 1.0-1.2 mg of Al/ml was administered rather than an aqueous preparation. The rates of 125I excretion were similarly influenced being statistically slower through the first week after single doses of the alum-precipitated preparations. The results of these studies strongly support the view that alum-precipitated vaccines offer more protection from system reactions than aqueous vaccines.