Use of the protein A-gold technique for the morphological study of vascular permeability.

The protein A-gold immunocytochemical technique has been applied for the ultrastructural study of vascular permeability. A capillary preparation was perfused for 30 min with a buffer solution containing albumin. After fixation and embedding, the albumin molecules were revealed on the tissue sections using anti-albumin antiserum and the protein A-gold complex. A specific labeling was obtained over the capillary lumen, the vesicular structures of the endothelial cells, and the intercapillary space. These results allowed us to conclude that the protein A-gold technique is suitable and of general applicability for the morphological study of vascular permeability.