A pharmaceutical composition comprising • a pharmaceutically effective amount of a trifunctional bispecific and/or trispecific antibody having the following properties: (a) binding to a T cell via CD3 and activating said T cell; (b) binding to an isolated target antigen which is separated from its natural context, e.g. a cell, a virus, a bacterium, a protozoan, or a fungus, and not associated with or being a part of said natural context; (c) binding via its Fc-portion or by a third specificity (in the case of trispecific antibodies) to Fcγ-receptor type I, IIa and/or III positive cells and initiating the production of cytokines or upregulation of costimulatory signals or a combination thereof and thereby activating T cells; (d) initiating interferon-gamma-accompanied TH1-biased T cell responses and humoral immune responses; and • an immunologically effective amount of said isolated target antigen and optionally one or more further isolated antigens in an immunologically effective amount wherein said antigens are present isolated from their natural context, e.g. a cell, a virus, a bacterium, a protozoan, or a fungus, and not associated with or being a part of said natural context; and a pharmaceutically acceptable carrier, for use in a method of immunizing a mammal subject, comprising administering to said subject a pharmaceutically effective amount of said pharmaceutical composition to evoke a cell-mediated or a humoral immune response or a combination thereof against said target antigen and said optionally one or more further antigens to immunize said mammal subject against said one or more antigens. • a pharmaceutically effective amount of a trifunctional bispecific and/or trispecific antibody having the following properties: (a) binding to a T cell via CD3 and activating said T cell; (b) binding to an isolated target antigen which is separated from its natural context, e.g. a cell, a virus, a bacterium, a protozoan, or a fungus, and not associated with or being a part of said natural context; (c) binding via its Fc-portion or by a third specificity (in the case of trispecific antibodies) to Fcγ-receptor type I, IIa and/or III positive cells and initiating the production of cytokines or upregulation of costimulatory signals or a combination thereof and thereby activating T cells; (d) initiating interferon-gamma-accompanied TH1-biased T cell responses and humoral immune responses; and (a) binding to a T cell via CD3 and activating said T cell; (b) binding to an isolated target antigen which is separated from its natural context, e.g. a cell, a virus, a bacterium, a protozoan, or a fungus, and not associated with or being a part of said natural context; (c) binding via its Fc-portion or by a third specificity (in the case of trispecific antibodies) to Fcγ-receptor type I, IIa and/or III positive cells and initiating the production of cytokines or upregulation of costimulatory signals or a combination thereof and thereby activating T cells; (d) initiating interferon-gamma-accompanied TH1-biased T cell responses and humoral immune responses; and • an immunologically effective amount of said isolated target antigen and optionally one or more further isolated antigens in an immunologically effective amount wherein said antigens are present isolated from their natural context, e.g. a cell, a virus, a bacterium, a protozoan, or a fungus, and not associated with or being a part of said natural context; and a pharmaceutically acceptable carrier,