[Evaluation of an immunochromatographic fourth generation test for the rapid diagnosis of acute HIV infection]

Clinical Outcomes of Post-exposure Prophylaxis following Occupational Exposure to Human Immunodeficiency Virus at Dental Departments of Hiroshima University Hospital

Background

Dental professionals have so many opportunities to use injection needles and sharp instruments during dental treatment that they face an increased risk of needlestick injuries. This retrospective study reports the utilization and clinical outcomes of occupational post-exposure prophylaxis (PEP) with anti-retroviral agents after being potentially exposed to HIV at the dental departments of Hiroshima University Hospital.

Objective

This study reports the utilization and clinical outcomes of occupational post-exposure prophylaxis (PEP) with antiretroviral agents after being potentially exposed to HIV at dental departments of Hiroshima University Hospital.

Methods

Data on the clinical status of HIV-infected source patients and information on HIV-exposed dental professionals from 2007 to 2018 were collected.

Results

Five dentists with an average experience of 5.6 years (1-15 years) were exposed. The averaged CD4-positive cell number and HIV-RNA load were 1176 (768-1898) /μl and less than 20 copies/ml, respectively, in all the patients. Two of the five HIV exposed dentists received PEP. Three months after the exposures, all of their results were negative in HIV antibody/antigen tests.

Conclusion

These data might support the concept of “undetectable equals untransmittable”, although HIV exposure in this study was not through sexual transmission.

Acquired Removability of Aspartic Protease Inhibitors by Direct Biotinylation

Protease inhibitors are used as both research tools and therapeutics. Many of these inhibitors consist of substrate amino acid sequence-derived structure with a transition state mimic to interact with the active site of the protease, suppressing enzymatic activity. However, once they bind, macrodilution or protein denaturation is required to remove them, limiting their usage. In this study, we describe a removable protease inhibitor, which is a directly biotinylated analogue to control the activities of HIV-1 protease and human cathepsin D. In the substrate cleavage assay, we observed that the nanomolar inhibitory activities were lost upon the addition of streptavidin, while the enzymatic activities sufficiently recovered. HIV-1 protease mixed with the removable inhibitor, avoiding autolysis, was still active to be detected by adding streptavidin after one year at room temperature. We also observed that the inhibitor was an effective eluent for the simple detection of the activity of proteases purified from human serum and cells. These results demonstrate that direct biotinylation of protease inhibitors could be a novel method for controlling the enzymatic activity from OFF to ON. We proposed the phenomenon that binding equilibrium of inhibitor was shifted from protease to streptavidin with higher affinity, named "inhibitor stripping action by affinity competition", or ISAAC. We anticipate that ISAAC could be applicable for preservatives of proteases and activity-based diagnosis of protease related diseases. Furthermore, removable inhibitor to be designed for targeted proteases changing the inhibitor structure may elucidate enzymatic activity in intrinsic form with natural modifications from various biological samples.