Compositions relating to anti-IL-21 receptor antibodies

An isolated IL-21 receptor antigen binding protein, wherein said antigen binding protein comprises either:

• a. the heavy chain variable domain and the light chain variable domain of antibody 29G2 or 30G3;
• or
• b. the CDR1, CDR2, and CDR3 of the light chain variable domain sequence, and CDR1, CDR2, and CDR3 of the heavy chain variable domain sequence of the antibody 29G2 or 30G3 respectively;
• or
• c. the heavy chain variable domain of the 29G2 group or the 30G3 group of FIG. 12 and the light chain variable domain selected from the corresponding group of FIG. 13;
• or
• d. the light chain variable domain of the 29G2 group or the 30G3 group of FIG. 13, and the heavy chain variable domain selected from the corresponding group of FIG. 12;
• or
• e. the heavy chain CDR 1, 2, and 3 sequences of the antibodies of the 29G2 group or the 30G3 group, and light chain CDR 1, 2, and 3 sequences selected from the antibodies within the corresponding group of FIG. 13.