There is disclosed a method to prepare a vaccine effective against allergy which method comprises: providing a mixture of at least one allergy protein antigen with a proteosome preparation in the presence of detergent; removing detergent from said mixture by diafiltration or ultrafiltration to obtain a proteosome-antigen composition; and formulating said composition into a vaccine. The invention is particularly concerned with preparing a vaccine effective against cancer or a biologic threat agent. The invention also provides a vaccine or composition prepared by the method of the invention and for the use of such composition in the preparation of a medicament for preventing or treating infection, allergy, cancer or biologic threat agent in an animal.