Raman spectroscopy of HIV-1 antigen and antibody

Raman spectra of anti-HIV-1 antibody, HIV-1 antigen (p24), and HIV-1 antibody-antigen complex have been measured in near-infrared and UV regions: 785 nm; 830 nm; and 244 nm laser excitations. The spectrum of the HIV-1 antigen was excited with an infrared laser and contains numerous Raman peaks. The most prominent peaks are broad bands at 1343, 1449, 1609 and 1655 cm -1 , which are characteristic of the Raman spectra of biological cells. The UV Raman spectrum of the HIV-1 antigen has a completely different structure. It has two strong peaks at 1613 cm -1 and 1173 cm -1 . The peak at 1613 cm -1 is associated with vibrations of the aromatic amino acids tyrosine (Tyr) and tryptophan (Try). The second strongest peak at 1173 cm -1 is associated with the vibration of Tyr. The Raman peak pattern of the HIV-1 antigen-antibody complex is very similar to that of the HIV-1 antigen. The only difference is that the peak at 1007 cm -1 of the Raman spectrum of the HIV-1 antigen-antibody complex is slightly enhanced compared to that of the HIV-1 antigen. This indicates that the peaks of the HIV-1 antigen dominate the Raman spectrum of the HIV-1 antigen-antibody complex.