Polyclonal bispecific antibody compositions and method of use

A method for treating a patient infected with a pathogen, the method comprising:

• a) obtaining a sample of blood mononuclear cells comprising T-cells from a donor;
• b) activating one or more of the T-cells ex vivo by stimulating the T-cells with soluble anti-CD3 antibody and culture of the T-cells in the presence of T-cell growth factors 10 IU/ml to 500 IU/ml IL-2, or in the presence of 25 to 100 ng/ml IL-7 and 25 to 100 ng/ml IL-15;
• c) arming the activated T-cells with a heterogeneous population of polyclonal bispecific binding molecules where each bispecific binding molecule comprises a first and a second antigen binding moiety,
• wherein the first antigen binding moieties specifically bind to an antigen on the surface of a cytotoxic immune cell, said first antigen binding moieties being the same or different, and
• wherein the second antigen binding moieties are a heterogeneous polyclonal population of antigen binding moieties against multiple different epitopes on one or more pathogenic antigens expressed or presented on the surface of a cell infected with the pathogen, said antigens being the same or different,
• wherein the first antigen binding moiety is fused to the second antigen binding moiety to form the bispecific binding molecule, and
• d) administering the armed T-cells to the patient infected with the pathogen.