Antibody—antigen interactions studied by means of Raman spectroscopy

The percentages of secondary structure of rabbit IgG and anti‐IgG in the lyophilized solid and aqueous solution state were obtained from the Raman spectra. The Raman spectrum of the lyophilized IgG—anti‐IgG complex was also recorded. The vibrational results indicate that the percentages of secondary structure of IgG do not change when lyophilized IgG is dissolved in water. Moreover, the secondary structure of IgG and of anti‐IgG changes only very slightly as a consequence of the complex formation. However, the Raman spectra in the SS stretching region suggest that some changes in the molecular geometry around the SS bridges take place as a consequence of the IgG—anti‐IgG complex formation.