Diagnosis of HIV-1 infection by near-infrared spectroscopy: Analysis using molecular clones of various HIV-1 subtypes

Background: Previously, we investigated the possibility of using near-infrared (NIR) spectroscopy for the diagnosis of human immunodeficiency virus type-1 (HIV-1) infection. Here, we further analyze NIR spectra using molecular clones of various HIV-1 subtypes. Methods: Culture supernatants of pNL4-3- (HIV-1 molecular clone) or pUC18- (empty vector) transfected 2931 cells were used. In addition, culture supernatants obtained using pBal (HIV-1 subtype B molecular clone) or pIndieC (HIV-1 subtype C molecular clone) were used. Near-infrared radiation (NIR) spectra, obtained using the culture supernatants, were subjected to principal component analysis (PCA) to extract and analyze their properties. Results: The PCA demonstrated that HIV-1 in medium altered wavelength absorption at around 950 and 1030 nm, suggesting that the HIV-1 altered OH vibration in water. In addition, absorption varied among subtypes at around 950, 1030 and 1060 nm, suggesting that the interaction between HIV-1 and water varies among subtypes. Conclusions: These differences in the NIR spectra may make it possible to delineate HIV-1 subtypes spectroscopically. (C) 2011 Elsevier B.V. All rights reserved.