Treatment of HIV infection with either antiretroviral (ARV) therapy or neutralizing monoclonal antibodies (NAbs) leads to a reduction in HIV plasma virus. Both ARVs and NAbs prevent new rounds of viral infection, but NAbs may have the additional capacity to accelerate the loss of virus-infected cells through Fc gamma receptor (FcγR)-mediated effector functions, which should affect the kinetics of plasma-virus decline. Here, we formally test the role of effector function in vivo by comparing the rate and timing of plasma-virus clearance in response to a single-dose treatment with either unmodified NAb or those with either reduced or augmented Fc function. When infused into viremic simian HIV (SHIV)-infected rhesus macaques, there was a 21% difference in slope of plasma-virus decline between NAb and NAb with reduced Fc function. NAb engineered to increase FcγRIII binding and improve antibody-dependent cellular cytotoxicity (ADCC) in vitro resulted in arming of effector cells in vivo, yet led to viral-decay kinetics similar to NAbs with reduced Fc function. These studies show that the predominant mechanism of antiviral activity of HIV NAbs is through inhibition of viral entry, but that Fc function can contribute to the overall antiviral activity, making them distinct from standard ARVs.
Russian N. gonorrhoeae diagnostic NAATs comprise relatively good performance characteristics. However, larger studies are crucial and, beneficially, the Russian assays should also be evaluated to other international highly sensitive and specific, and ideally Food and Drug Administration approved, NAATs such as Aptima Combo 2 (Gen-Probe).
This study aimed to assess the laboratory diagnosis of Neisseria gonorrhoeae in St. Petersburg, Russia. In total, 334 consecutive symptomatic patients were enrolled. Cervical and urethral specimens from women (n=286) and urethral specimens from men (n=48) were analyzed by microscopy, culture and two in-house NAATs, i.e. polymerase chain reaction (PCR) and nucleic acid sequence-based amplification (NASBA), developed in Russia. All N. gonorrhoeae-positive samples were confirmed using porA pseudogene and 16S rRNA gene sequencing. All methods displayed 100% specificity, i.e. positive predictive values of 100%. Compared to the PCR (most sensitive method in the present study), in women the sensitivity of both microscopy and culture was 31.8%, and that of NASBA was 90.9%. In men, microscopy, culture and NASBA displayed a sensitivity of 75%, 50% and 100%, respectively. The negative predictive values of microscopy, culture, and NASBA were 97.3%, 97.3%, and 99.6% in women, and 97.8%, 95.7%, and 100% in men, respectively. According to the PCR, the prevalences of N. gonorrhoeae were 4.5% (women) and 8.3% (men). In conclusion, both the investigated Russian NAATs displayed a high sensitivity and specificity. However, in general the diagnosis of gonorrhoea in Russia is suboptimal and crucially requires validation, improvements and quality assurance.
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