The present invention refers to a pharmaceutical composition containing trifunctional bispecific and/or trispecific antibodies being capable of binding to a specific target antigen(s) for use in a method of immunizing mammals against diseases in which said target antigen(s) is (are) involved, and further to a pharmaceutical composition containing trifunctional bispecific and/or trispecific antibodies being capable of binding to (a) specific target antigen (s) which is (are) involved in a disease of a mammal, specifically a human.