Inhibition of immune complex formation

A method of designing a ligand having specific binding affinity for the CH2-CH3 cleft of an immunoglobulin molecule having bound antigen, said method comprising:

• a) providing data to a specifically programmed computer, said data comprising the atomic coordinates of the amino acid residues at positions 252, 253, 435, and 436 within said CH2-CH3 cleft, and said computer having a computer program capable of generating an atomic model of a molecule from said atomic coordinate data;
• b) generating with said computer an atomic model of said CH2-CH3 cleft;
• c) providing to said computer data comprising the atomic coordinates of a candidate compound;
• d) generating with said computer an atomic model of said candidate compound optimally positioned in said CH2-CH3 cleft;
• e) outputting to a display said atomic model of said candidate compound optimally positioned in said CH2-CH3 cleft;
• f) determining whether said optimally positioned candidate compound interacts with said amino acid residues within said CH2-CH3 cleft;
• and
• g) identifying said candidate compound as a ligand having specific binding affinity for said CH2-CH3 cleft if said candidate compound interacts with said amino acid residues.