Activation and expansion of T-cells using an engineered multivalent signaling platform as a research tool

An in vitro method for expanding a population of T cells, the method comprising:

• contacting said population of T cells with an engineered K562 cell followed by restimulation of said T cells with said engineered K562 cell, wherein said engineered K562 cell comprises:
• 1) an exogenous antibody that binds to CD3 or wherein the antibody is loaded onto a human Fcγ receptor wherein the Fcγ receptor is expressed from an expression vector in said engineered K562 cell, 2) a molecule that binds CD28 selected from the group consisting of anti-CD28 antibody;
• and 3) 4-1BBL;
• and
• culturing said T cells under conditions and time sufficient to induce cell division, wherein said contacting occurs in the absence of exogenously added cytokines, thereby expanding said population of T cells.

An in vitro method for expanding a population of T cells, said method comprising:

• contacting said population of T cells with an engineered K562 cell followed by restimulation of said T cells with said engineered K562 cell, wherein said engineered K562 cell comprises:
• 1) an exogenous antibody that binds to CD3 or wherein the antibody is loaded onto a human Fcγ receptor wherein the Fcγ receptor is expressed from an expression vector in said engineered K562 cell, 2) a molecule that binds CD28 selected from the group consisting of anti-CD28 antibody, CD80, CD86;
• and 3) 4-1BBL;
• and culturing said T cells under conditions and time sufficient to induce cell division thereby expanding said population of T cells.

An ex vivo method for expanding antigen specific T cells, the method comprising:

• a. contacting a population of T cells with an antigen for a time sufficient to induce activation of T cells specific to said antigen;
• and
• b. contacting said population of antigen-specific T cells ex vivo with an engineered K562 cell under conditions and for time sufficient to induce proliferation of said antigen-specific T cells followed by restimulation of said T cells with said engineered K562 cell, wherein said engineered K562 cell comprises:
• 1) an exogenous antibody that binds to CD3 or CD2, wherein the antibody is loaded onto a human Fcγ receptor wherein the Fcγ receptor is expressed from an expression vector in said engineered K562 cell, 2) a molecule that binds CD28 selected from the group consisting of anti-CD28 antibody, CD80, and CD86;
• and 3) 4-1BBL, thereby expanding said antigen specific T cells.