HUMANIZED ANTIBODY OR FRAGMENT THEREOF SPECIFIC FOR CD3

1 ) A humanized antibody or fragment thereof specific for the antigen CD3, wherein said antibody or fragment thereof comprises a heavy chain variable domain comprising a CDR1 region of SEQ ID NO:1, a CDR2 region of SEQ ID NO:2, and a CDR3 region of SEQ ID NO:3, and a light chain variable domain comprising a CDR1 region of SEQ ID NO:4, a CDR2 region of SEQ ID NO:5, and a CDR3 region of SEQ ID NO:6.

2 ) The antibody or fragment thereof according to claim 1 , wherein the framework regions of the heavy chain variable domain are amino acid sequences having an identity of at least 70% to the framework regions FR1, FR2, FR3, and FR4 of SEQ ID NO:16, and wherein the framework regions of the light chain variable domain are amino acid sequences having an identity of at least 70% to the framework regions FR1, FR2, FR3, and FR4 of SEQ ID NO:17.

3 ) The antibody or fragment thereof according to claim 1 or 2 , wherein said heavy chain variable domain comprises the sequence of SEQ ID NO:16 and said light chain variable domain comprises the sequence of SEQ ID NO:17.

4 ) A method for polyclonal stimulation of T cells comprising contacting a population of T cells with an anti-CD3 antibody or fragment thereof according to any one of claims 1 to 3 , and wherein said anti-CD3 antibody or fragment thereof is linked to particles.

5 ) The method according to claim 4 , wherein said population of T cells is additionally contacted with a humanized anti-CD28 antibody or fragment thereof, wherein said anti-CD28 antibody or fragment thereof comprises a heavy chain variable domain comprising a CDR1 region of SEQ ID NO:7, a CDR2 region of SEQ ID NO:8, and a CDR3 region of SEQ ID NO:9, and a light chain variable domain comprising a CDR1 region of SEQ ID NO:10, a CDR2 region of SEQ ID NO:11, and a CDR3 region of SEQ ID NO:12, and wherein said anti-CD28 antibody or fragment thereof is linked to the same or to separate particles regarding the particles to which the anti-CD3 antibody is linked.

6 ) The method according to claim 4 or 5 , wherein said particles are beads with a solid phase surface ranging in size between 500 nm to 10 μm.

7 ) The method according claim 5 , wherein said particles are nanomatrices, the nanomatrices comprising

a) matrices of mobile polymer chains, and

b) attached to said matrices of mobile polymer chains said anti-CD3 antibody or fragment thereof and said anti-CD28 antibody or fragment thereof,

wherein said nanomatrices are 1 to 500 nm in size.

8 ) The method according to any one of claims 4 to 7 , wherein said method is performed in a closed and sterile cell culture system.

9 ) A cell composition obtained by the method according to claim 8 for use in cell therapy.

10 ) The use of an anti-CD3 antibody or fragment thereof according to claims 1 to 3 for reversible tagging of cells, wherein said anti-CD3 antibody or fragment thereof is linked to a tag.

11 ) The use according to claim 10 , wherein said anti-CD3 antibody or fragment thereof is used in combination with an anti-CD28 antibody or fragment thereof, wherein said anti-CD28 antibody or fragment thereof comprises a heavy chain variable domain comprising a CDR1 region of SEQ ID NO:7, a CDR2 region of SEQ ID NO:8, and a CDR3 region of SEQ ID NO:9, and a light chain variable domain comprising a CDR1 region of SEQ ID NO:10, a CDR2 region of SEQ ID NO:11, and a CDR3 region of SEQ ID NO:12.

12 ) Isolated polynucleotides encoding for a humanized anti-CD3 antibody or fragment thereof according to any one of claims 1 to 3 .

13 ) An expression vector comprising polynucleotides according to claim 12 .

14 ) A host cell comprising an expression vector according to claim 13 .