ANTI-HER2 ANTIBODY, A NUCLEIC ACID MOLECULE ENCODING THE VARIABLE REGION OF SAID ANTIBODY, A METHOD OF DETECTING HER2 IN A BIOLOGICAL SAMPLE, AN IMMUNO-ENZYMATIC ELISA ASSAY AND USE OF SAID ANTI-HER2 ANTIBODY OR FRAGMENTS THEREFOF

Invention relates to an anti-HER2 antibody, characterised in that it comprises: a) a heavy chain variable region comprising CDR1, CDR2 and CDR3, in which CDR1 is an amino acid sequence of GYSFTGYN (SEQ ID No. 1) or GYSFTDYN (SEQ ID No. 2), CDR2 is an amino acid sequence of IDPNYGT (SEQ ID No. 3) or IDHYNGNT (SEQ ID No. 4), CDR3 is an amino acid sequence of ARRKVNYEAWFAF (SEQ ID No. 5) or ARHYDYGAMDY (SEQ ID No. 6); b) a light chain variable region comprising CDR1, CDR2 and CDR3 in which CDR1 is an amino acid sequence of ESVDSYGNSF (SEQ ID No. 7) or QNVGTN (SEQ ID No. 8), CDR2 is an amino acid sequence of RAS (SEQ ID No. 9) or SAS (SEQ ID No. 10), CDR3 constitutes an amino acid sequence of QQSNEDPFT (SEQ ID No. 11) or QHYYIYPLT (SEQ ID No. 12). Invention further relates to a nucleic acid molecule encoding the variable region of an antibody according to invention or a fragment thereof. Invention further relates to a method of detecting HER2 in a biological sample, comprising contacting the sample with an HER2-binding protein and detecting a complex, wherein the detection of said complex indicates HER2 expression in the sample, characterised in that HER2-binding protein is the antibody according to invention. Invention further relates to an immuno-enzymatic ELISA assay for the detection of HER2 antigen, characterised in that at least one antibody according to invention is used for the detection of antigen. Invention further relates to the use of antibody according to invention for producing antibody-drug conjugates and to the use of SEQ ID No. 17-28 nucleotide sequences encoding variable regions of the antibodies according to invention for the CAR-T production.