High resolution electron micrograph of a thin frozen section treated with a clone of the mAb (D40-2) used to show the A4 antigen on decorated tubules. The immunogold lies along the outer margin of these tubules for the most part. Mitochondria are not labeled. TEM taken on 2/10/93 by R. Allen with Zeiss 10A operating at 80kV. Neg. 19,800X. Cells were lightly fixed with 0.25% glutaraldehyde and infiltrated with 2.3M sucrose before being frozen in liquid nitrogen and thin sectioned at a temperature of –100°C at approximately 75nm thickness. Frozen sections from these preparations were then thawed, washed, and exposed to a monoclonal primary antibody that was raised in mice or rabbit/goat and to colloidal gold-complexed goat-anti-mouse/rabbit secondary antibodies. Further details of preparation are outlined in Methods Cell Biol. 2010;96:143-73. The raw film was scanned with an Epson Perfection V750 Pro. This image is best used for quantitative analysis. Additional information available at (http://www5.pbrc.hawaii.edu/allen/).