Claim 1: an isolated monoclonal antibody that binds specifically binds to human IL - 17a, or fragment that contains the variable regions of heavy chain (VH) and Light (VL), where the Antibody or Fragment of this includes: (a) the variable domain of heavy chain (VH) Comprising 3 hcdr1 hcdr2 hypervariable regions, and hcdr3,Where hcdr1 comprising the amino acid sequence of SEQ ID no. 1: F - T - F - S - - - - x u00b3 u00b9 x u00b3 u00b2 x u00b3 u00b3 x u00b3 u2074 - x u00b3 u2075 (according to Kabat numbering Index), where x u00b3 u00b9 is an amino acid selected from the group consisting of N, D, K, L, p or t x u00b3 u00b2 is； an amino acid selected from the Group comprising E and F； x u00b3 u00b3 is an amino acid selected from the Group comprising a, G, N, S,T or V； x u00b3 u2074 is an amino acid selected from the Group comprising m e I； x u00b3 u2075 is an amino acid selected from the Group comprising n s, G, or t； hcdr2 comprising the amino acid sequence of SEQ ID no. 2: x u2075 u2070 x u2075 u00b2 x u2075 u00b2 u1d43 - i - - - - - - x u2075 u00b2 u1d47 x u2075 u00b3 x u2075 u2075 - G x u2075 u2076 - x u2075 u2077 - x u2075 u2078, Where x u2075 u2070 is an amino acid selected from the group consisting of R, G, I, L,M and S； x u2075 u00b2 is an amino acid selected from the group consisting of D and E； x u2075 u00b2 u1d43 is an amino acid selected from the Group comprising G and M； x u2075 u00b2 u1d47 is an amino acid selected from the Group comprising G, L, r, V； x u2075 u00b3 is an amino acid selected from the group consisting of I and l； x u2075 u2075 is an amino acid selected from the group consisting of S, T, L,R and W； x u2075 u2076 is an amino acid selected from the group consisting of S, T, and S E； 57 is an amino acid selected from the group consisting of S, T, L, R and W； x u2075 u2078 is an amino acid selected from the Group comprising y, T, L and K； hcdr3 comprising The Amino Acid Sequence the SEQ ID no. 3: C - A - x u2079 u2075 x u2079 u2074 - - and - -
