The present invention relates to antibodies or fragments thereof that specifically bind FcγRIIB with greater affinity than said antibodies or fragments thereof bind FcγRIIA. The present invention also encompasses the use of an anti-FcγRIIB antibody or an antigen-binding fragment thereof for the treatment, prevention, management, or amelioration of a disease or disorder. The invention further provides methods of enhancing the therapeutic effect of therapeutic antibodies by administering the antibodies of the invention to enhance the effector function of the therapeutic antibodies. The invention also provides methods of enhancing efficacy of a vaccine composition by administering the antibodies of the invention with a vaccine composition. The invention also provides methods of breaking tolerance to an antigen by administering an antigen-antibody complex and an antibody of the invention.