Human defensins 5 and 6 enhance HIV-1 infectivity through promoting HIV attachment.

BACKGROUND: Concurrent sexually transmitted infections (STIs) increase the likelihood of HIV transmission. The levels of defensins are frequently elevated in genital fluids from individuals with STIs. We have previously shown that human defensins 5 and 6 (HD5 and HD6) promote HIV entry and contribute to Neisseria gonorrhoeae-mediated enhancement of HIV infectivity in vitro. In this study, we dissect the molecular mechanism of the HIV enhancing effect of defensins. RESULTS: HD5 and HD6 primarily acted on the virion to promote HIV infection. Both HD5 and HD6 antagonized the anti-HIV activities of inhibitors of HIV entry (TAK 779) and fusion (T-20) when the inhibitors were present only during viral attachment; however, when these inhibitors were added back during viral infection they overrode the HIV enhancing effect of defensins. HD5 and HD6 enhanced HIV infectivity by promoting HIV attachment to target cells. Studies using fluorescent HIV containing Vpr-GFP indicated that these defensins enhanced HIV attachment by concentrating virus particles on the target cells. HD5 and HD6 blocked anti-HIV activities of soluble glycosaminoglycans including heparin, chondroitin sulfate, and dextran sulfate. However, heparin, at a high concentration, diminished the HIV enhancing effect of HD5, but not HD6. Additionally, the degree of the HIV enhancing effect of HD5, but not HD6, was increased in heparinase-treated cells. These results suggest that HD5 and haparin/heparan sulfate compete for binding to HIV. CONCLUSIONS: HD5 and HD6 increased HIV infectivity by concentrating virus on the target cells. These defensins may have a negative effect on the efficacy of microbicides, especially in the setting of STIs.

Refining the utility and role of Frozen section in head and neck squamous cell carcinoma resection.

OBJECTIVES/HYPOTHESIS: Previous studies report high-accuracy rates for intraoperative frozen sections, but reliability of frozen sections in predicting the ultimate final margin status is unknown. We compared frozen and permanent reads to identify risk factors for overall discrepancies between intraoperative and final margin status. STUDY DESIGN: Retrospective chart review. METHODS: Pathology reports of 437 surgical resections between 2010 and 2013 were retrospectively reviewed. A total of 253 cases, generating 1,109 individual specimens, met inclusion criteria. Patient demographics, treatment, recurrence, and survival, as well as pathology data pertaining to the specimen, were recorded. RESULTS: Frozen read accuracy was 96.7% (83.1% sensitivity, 97.9% specificity) relative to permanent evaluation. However, 4.3% of cases had a final positive margin not detected by frozen section; 17.8% had a close margin not detected by frozen section. In eight of 11 cases with missed positive margins, the involved margin was never sampled intraoperatively. Cases where intraoperative margins were only taken from surrounding tissue had a higher risk of missing a close or positive final margin when compared to cases where some or all margins were taken from the specimen (odds ratio = 5.05, 95% confidence interval [2.31, 11.07], P <0.0001). Disease subsite, risk score, prior radiation, staging, and p16 expression were not significantly associated with the likelihood of missing a close or positive final margin. CONCLUSION: Individual frozen section reads are highly accurate. However, negative intraoperative margins do not guarantee margin-negative resections. The process of selecting representative margins for intraoperative analysis, specifically the practice of sampling the resection bed, should be refined. LEVEL OF EVIDENCE: N/A. Laryngoscope, 126:1768-1775, 2016.