Which New Health Technologies Do We Need to Achieve an End to HIV/AIDS?

Synthetic neoglycoconjugates of hepta- and nonamannoside ligands for eliciting oligomannose-specific HIV-1-neutralizing antibodies

Oligomannose-type glycans on the spike protein of HIV-1 constitute relevant epitopes to elicit broadly neutralizing antibodies (bnAbs). Herein we describe an improved synthesis of α- and β-linked hepta- and nonamannosyl ligands that, subsequently, were converted into BSA and CRM 197 neoglycoconjugates. We assembled the ligands from anomeric 3-azidopropyl spacer glycosides from select 3-O-protected thiocresyl mannoside donors. Chain extensions were achieved using 4+3 or 4+5 block synthesis of thiocresyl and trichloroacetimidate glycosyl donors. Subsequent global deprotection generated the 3-aminopropyl oligosaccharide ligands. ELISA binding data obtained with the β-anomeric hepta- and nonamannosyl conjugates with a selection of HIV-1 bnAbs showed comparable binding of both mannosyl ligands by Fab fragments yet lesser binding of the nonasaccharide conjugate by the corresponding IgG antibodies. These results support previous observations that a complete Man 9 structure might not be the preferred antigenic binding motif for some oligomannose-specific antibodies and have implications for glycoside designs to elicit oligomannose-targeted HIV-1-neutralizing antibodies.

Health trends, inequalities and opportunities in South Africa's provinces, 1990-2019: findings from the Global Burden of Disease 2019 Study

BACKGROUND

Over the last 30 years, South Africa has experienced four 'colliding epidemics' of HIV and tuberculosis, chronic illness and mental health, injury and violence, and maternal, neonatal, and child mortality, which have had substantial effects on health and well-being. Using data from the 2019 Global Burden of Diseases, Injuries and Risk Factors Study (GBD 2019), we evaluated national and provincial health trends and progress towards important Sustainable Development Goal targets from 1990 to 2019.

METHODS

We analysed GBD 2019 estimates of mortality, non-fatal health loss, summary health measures and risk factor burden, comparing trends over 1990-2007 and 2007-2019. Additionally, we decomposed changes in life expectancy by cause of death and assessed healthcare system performance.

RESULTS

Across the nine provinces, inequalities in mortality and life expectancy increased over 1990-2007, largely due to differences in HIV/AIDS, then decreased over 2007-2019. Demographic change and increases in non-communicable diseases nearly doubled the number of years lived with disability between 1990 and 2019. From 1990 to 2019, risk factor burdens generally shifted from communicable and nutritional disease risks to non-communicable disease and injury risks; unsafe sex remained the top risk factor. Despite widespread improvements in healthcare system performance, the greatest gains were generally in economically advantaged provinces.

CONCLUSIONS

Reductions in HIV/AIDS and related conditions have led to improved health since 2007, though most provinces still lag in key areas. To achieve health targets, provincial governments should enhance health investments and exchange of knowledge, resources and best practices alongside populations that have been left behind, especially following the COVID-19 pandemic.

Willingness to use HIV prevention methods among vaccine efficacy trial participants in Soweto, South Africa: discretion is important

BACKGROUND

Despite multiple available HIV prevention methods, the HIV epidemic continues to affect South Africa the most. We sought to understand willingness to use actual and hypothetical HIV prevention methods among participants enrolled in a preventative HIV vaccine efficacy trial in Soweto, South Africa.

METHODS

We conducted a qualitative study with 38 self-reporting HIV-uninfected and consenting 18-35 year olds participating in the HVTN 702 vaccine efficacy trial in Soweto. Using a semi-structured interview guide, five focus group discussions (FGDs) were held, stratified by age, gender and sexual orientation. The FGDs were composed of: (i) 10 heterosexual women aged 18-24 years; (ii) 9 heterosexual and bisexual women aged 25-35 years; (iii & iv) heterosexual men aged 25-35 years with 7 in both groups; and (v) 5 men aged 18-35 years who have sex with men. FGDs were audio-recorded, transcribed verbatim, translated into English and analysed using thematic analysis.

RESULTS

We present five main themes: (i) long-lasting methods are preferable; (ii) condoms are well-known but not preferred for use; (iii) administration route of HIV prevention method is a consideration for the user; (iv) ideal HIV prevention methods should blend into the lifestyle of the user; and the perception that (v) visible prevention methods indicate sexual indiscretion.

CONCLUSIONS

The participants' candour about barriers to condom and daily oral pre-exposure prophylaxis (PrEP) use, and expressed preferences for long-lasting, discreet, lifestyle-friendly methods reveal a gap in the biomedical prevention market aiming to reduce sexually acquired HIV in South Africa. Product developers should consider long-acting injectable formulations, such as vaccines, passive antibodies and chemoprophylaxis, for HIV prevention technologies. Future innovations in HIV prevention products may need to address the desire for the method to blend easily into lifestyles, such as food-medication formulations.

Optimizing Interventions Across the HIV Care Continuum: A Case Study Using Process Improvement Analysis

UNAIDS' 90-90-90 goal for 2020 is for 90% of HIV-infected people to know their status, 90% of infected individuals to receive antiretroviral therapy (ART), and 90% of those on ART to achieve viral suppression. To achieve these ambitious goals, effective care delivery programs are needed. In this paper we present a case study showing how HIV care can be improved by viewing the patient care process as a production process and applying methods of process improvement analysis. We examine the continuum of HIV care at a hospital-based HIV clinic in Kingston, Jamaica. We perform qualitative analysis to identify key programmatic, personnel, and clinical areas for process improvement. We then perform quantitative analysis. We develop a stochastic model of the care process which we use to evaluate the effects of potential process improvements on the number of patients who receive ART and the number who achieve viral suppression. We also develop a model for optimal investment of a fixed budget among interventions aimed at improving the care cascade and we use the model to determine the optimal investment among three interventions that the clinic could invest in. By viewing the patient care process as a production process and applying qualitative and quantitative process improvement analysis, our case study illustrates how clinics can identify the best ways to maximize clinical outcomes. Our methods are generalizable to other HIV care clinics as well as to clinics that provide care for other chronic conditions (e.g., diabetes, hepatitis B, or opioid use disorder).

Serum alpha-mannosidase as an additional barrier to eliciting oligomannose-specific HIV-1-neutralizing antibodies

Oligomannose-type glycans on HIV-1 gp120 form a patch that is targeted by several broadly neutralizing antibodies (bnAbs) and that therefore is of interest to vaccine design. However, attempts to elicit similar oligomannose-specific bnAbs by immunizing with oligomannosidic glycoconjugates have only been modestly successful so far. A common assumption is that eliciting oligomannose-specific bnAbs is hindered by B cell tolerance, resulting from the presented oligomannosides being sensed as self molecules. Here, we present data, along with existing scientific evidence, supporting an additional, or perhaps alternate, explanation: serum mannosidase trimming of the presented oligomannosides in vivo. Mannosidase trimming lessens the likelihood of eliciting antibodies with capacity to bind full-sized oligomannose, which typifies the binding mode of existing bnAbs to the oligomannose patch. The rapidity of the observed trimming suggests the need for immunization strategies and/or synthetic glycosides that readily avoid or resist mannosidase trimming upon immunization and can overcome possible tolerance restrictions.

Robotic selection for the rapid development of stable CHO cell lines for HIV vaccine production

The production of envelope glycoproteins (Envs) for use as HIV vaccines is challenging. The yield of Envs expressed in stable Chinese Hamster Ovary (CHO) cell lines is typically 10-100 fold lower than other glycoproteins of pharmaceutical interest. Moreover, Envs produced in CHO cells are typically enriched for sialic acid containing glycans compared to virus associated Envs that possess mainly high-mannose carbohydrates. This difference alters the net charge and biophysical properties of Envs and impacts their antigenic structure. Here we employ a novel robotic cell line selection strategy to address the problems of low expression. Additionally, we employed a novel gene-edited CHO cell line (MGAT1- CHO) to address the problems of high sialic acid content, and poor antigenic structure. We demonstrate that stable cell lines expressing high levels of gp120, potentially suitable for biopharmaceutical production can be created using the MGAT1- CHO cell line. Finally, we describe a MGAT1- CHO cell line expressing A244-rgp120 that exhibits improved binding of three major families of bN-mAbs compared to Envs produced in normal CHO cells. The new strategy described has the potential to eliminate the bottleneck in HIV vaccine development that has limited the field for more than 25 years.

Combining biomedical preventions for HIV: Vaccines with pre-exposure prophylaxis, microbicides or other HIV preventions

Biomedical preventions for HIV, such as vaccines, microbicides or pre-exposure prophylaxis (PrEP) with antiretroviral drugs, can each only partially prevent HIV-1 infection in most human trials. Oral PrEP is now FDA approved for HIV-prevention in high risk groups, but partial adherence reduces efficacy. If combined as biomedical preventions (CBP) an HIV vaccine could provide protection when PrEP adherence is low and PrEP could prevent vaccine breakthroughs. Other types of PrEP or microbicides may also be partially protective. When licensed, first generation HIV vaccines are likely to be partially effective. Individuals at risk for HIV may receive an HIV vaccine combined with other biomedical preventions, in series or in parallel, in clinical trials or as part of standard of care, with the goal of maximally increasing HIV prevention. In human studies, it is challenging to determine which preventions are best combined, how they interact and how effective they are.

Animal models can determine CBP efficacy, whether additive or synergistic, the efficacy of different products and combinations, dose, timing and mechanisms. CBP studies in macaques have shown that partially or minimally effective candidate HIV vaccines combined with partially effective oral PrEP, vaginal PrEP or microbicide generally provided greater protection than either prevention alone against SIV or SHIV challenges. Since human CBP trials will be complex, animal models can guide their design, sample size, endpoints, correlates and surrogates of protection. This review focuses on animal studies and human models of CBP and discusses implications for HIV prevention.

Investing in Health Innovation: A Cornerstone to Achieving Global Health Convergence

Gavin Yamey and Carlos Morel, coordinators of a new PLOS collection on the innovations needed to reduce infectious, maternal, and child deaths to universally low levels, highlight the key cross-cutting themes emerging from the collection.