Model of an antibody-antigen complex (surface representation).

"An antibody (Ab), also known as an immunoglobulin (Ig), is a large Y-shaped protein produced by B cells that is used by the immune system to identify and neutralize foreign objects such as bacteria and viruses."
http://en.wikipedia.org/wiki/Antibody

These models consist of fragments of a mouse IGG Fab antibody "heavy chain" (Orange) , antibody "light chain" (Blue), and the antigen, hen egg-white lysozyme (Green).

Model based on the Protein Data Bank entry 1YQV:
http://www.rcsb.org/pdb/explore/explore.do?structureId=1yqv

STL file created using VMD:
http://www.ks.uiuc.edu/Research/vmd/

Successfully printed by a Replicator 2 in PLA using MakerWare(TM) 2.2.2.89, standard resolution (2 shells, 10% infill), with raft and supports. The models can be printed separately in different colors. In the pictures, the heavy chain is orange, the light chain is blue and lysozyme is green.