An inert polymer pellet less than 1 mm in diameter, implanted subcutaneously in mice,
releases free antigen continuously and enhances antibody formation for over 6 months. The
immune response stimulated by sustained antigen delivery is comparable to the secondary
response induced by the same total dose of antigen emulsified in complete Freund's
adjuvant. The sustained release polymer implants, using antigens over a wide molecular
weight range, proved effective in eliciting prolonged antibody formation. The antigens tested …