Identification of herpes simplex virus type 1 infection by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

This study aimed to investigate whether Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) could identify Herpes simplex virus type 1 (HSV1) infection in samples in vitro and in vivo. MS spectra of supernatants and suspensions from infected human cornea epithelial (HCE) cell culture samples and infected samples of BALB/c mouse corneas were obtained by a VITEK® mass spectrometer. The discriminating peaks between infected and non-infected samples were used to establish discriminating superspectra (DSPc for cells and DSPm for corneas) by SARAMIS™ software. Another infected cells with two viral titers and infected cornea samples were used for blind testing against two DSPs. The results showed that automatic matching by the SARAMIS system revealed 28 discriminating peaks in HSV1-infected cells and 17 discriminating peaks in HSV1 keratitis, generating two discriminating superspectra (DSPs). Blind testing of virus-infected samples demonstrated a high positive identification rate for both in vitro and in vivo DSPs. The positive identification rate varied with viral titers, with cell suspensions exhibiting significantly higher rates compared to supernatants. Cluster analysis based on MS spectra revealed that there were more obvious differences between in vivo and in vitro samples compared to the differences between infected and non-infected samples. These findings suggest that MALDI-TOF MS can directly identify HSV1 in vitro or in vivo infected specimens, with higher positivity rates achieved when using cellular suspensions directly. This is an attempt on the method of virus detection, which shows potential for using MS to detect HSV1 infection or other virus infection in humans.