A Model Experiment to Develop a High Resolving Power Analysis of Immunoelectron Microscopy

For the purpose of developing a high resolving power immunoelectron microscopy, a topographical correlation between antigen molecules and protein A-gold (PAG) particles which localized as an immunocytochemical probe was investigated. Ultrathin sections which contain linear arrayed G-actin molecules in JB-4 resin, were labeled with anti-actin antibody and subsequently with PAG. The histogram obtained from the immunoelectron microscopy shows a unimodal distribution, which has a peak at the G-actin layer. To improve resolution, interval width (IW) was changed from 50 to 10Å. When the finest IW was used for the analysis, a lot of irregular noises became remarkable. By applying 5-point moving averages, a smoothed curve was obtained even for the data using IW of 10Å. A resolution which could be expressed as a minimal length of two peaks which were distinguishable in an added histogram, was estimated as 60Å. A theoretical meaning of the histogram was discussed in connection with the post-embedding labeling.