Designing of novel antigenic peptide cocktail for the detection of antibodies to HIV-1/2 by ELISA

Role of Peptides in Diagnostics

The specificity of a diagnostic assay depends upon the purity of the biomolecules used as a probe. To get specific and accurate information of a disease, the use of synthetic peptides in diagnostics have increased in the last few decades, because of their high purity profile and ability to get modified chemically. The discovered peptide probes are used either in imaging diagnostics or in non-imaging diagnostics. In non-imaging diagnostics, techniques such as Enzyme-Linked Immunosorbent Assay (ELISA), lateral flow devices (i.e., point-of-care testing), or microarray or LC-MS/MS are used for direct analysis of biofluids. Among all, peptide-based ELISA is considered to be the most preferred technology platform. Similarly, peptides can also be used as probes for imaging techniques, such as single-photon emission computed tomography (SPECT) and positron emission tomography (PET). The role of radiolabeled peptides, such as somatostatin receptors, interleukin 2 receptor, prostate specific membrane antigen, αβ3 integrin receptor, gastrin-releasing peptide, chemokine receptor 4, and urokinase-type plasminogen receptor, are well established tools for targeted molecular imaging ortumor receptor imaging. Low molecular weight peptides allow a rapid clearance from the blood and result in favorable target-to-non-target ratios. It also displays a good tissue penetration and non-immunogenicity. The only drawback of using peptides is their potential low metabolic stability. In this review article, we have discussed and evaluated the role of peptides in imaging and non-imaging diagnostics. The most popular non-imaging and imaging diagnostic platforms are discussed, categorized, and ranked, as per their scientific contribution on PUBMED. Moreover, the applicability of peptide-based diagnostics in deadly diseases, mainly COVID-19 and cancer, is also discussed in detail.

multiSero: open multiplex-ELISA platform for analyzing antibody responses to SARS-CoV-2 infection

Serology has provided valuable diagnostic and epidemiological data on antibody responses to SARS-CoV-2 in diverse patient cohorts. Deployment of high content, multiplex serology platforms across the world, including in low and medium income countries, can accelerate longitudinal epidemiological surveys. Here we report multiSero, an open platform to enable multiplex serology with up to 48 antigens in a 96-well format. The platform consists of three components: ELISA-array of printed proteins, a commercial or home-built plate reader, and modular python software for automated analysis (pysero). We validate the platform by comparing antibody titers against the SARS-CoV-2 Spike, receptor binding domain (RBD), and nucleocapsid (N) in 114 sera from COVID-19 positive individuals and 87 pre-pandemic COVID-19 negative sera. We report data with both a commercial plate reader and an inexpensive, open plate reader (nautilus). Receiver operating characteristic (ROC) analysis of classification with single antigens shows that Spike and RBD classify positive and negative sera with the highest sensitivity at a given specificity. The platform distinguished positive sera from negative sera when the reactivity of the sera was equivalent to the binding of 1 ng mL⁻¹ RBD-specific monoclonal antibody. We developed normalization and classification methods to pool antibody responses from multiple antigens and multiple experiments. Our results demonstrate a performant and accessible pipeline for multiplexed ELISA ready for multiple applications, including serosurveillance, identification of viral proteins that elicit antibody responses, differential diagnosis of circulating pathogens, and immune responses to vaccines.

Prevention of mother-to-child transmission (PMTCT) of HIV: a review of the achievements and challenges in Burkina-Faso

BACKGROUND

Burkina-Faso's HIV/AIDS program is one of the most successful in Africa, with a declining HIV prevalence and treatment outcomes that rival those of developed countries. Prevention of mother-to-child transmission (PMTCT) guidelines in Burkina-Faso, initiated in the year 2000, were revised in 2004, 2006 and 2010. The guideline document has since undergone several stages of improvement, largely based on recommendations from WHO, with adaptations by local experts in the field. Option B+ adopted since August 2014 in Burkina-Faso has enabled maintenance of mothers on longer treatment and increasing their survival and that of their children. Through this review, we describe the achievements and challenges of HIV PMTCT programs in Burkina-Faso.

AIMS OF STUDY

This study had the following objectives: 1) describing the historical perspective of PMTCT implementation in Burkina-Faso; 2) presenting the effectiveness of interventions at improving PMTCT service delivery and promoting retention of mothers and babies in care; and 3) determining the impact of male partner involvement on PMTCT in Burkina-Faso.

METHODOLOGY

A literature search was conducted in PubMed and Google. Search terms included the following keywords: "HIV testing"; "prevention"; "mother"; "child"; "male partner"; "counseling"; "involvement"; "participation"; and the grouped terms "PMTCT and partners"; "VCT"; "barriers and/or factors"; "Male involvement in PMTCT"; and "Burkina-Faso". Data collection took place from May to October 2015. The search was limited to articles published between January 2002 and December 2015. UNICEF and UNAIDS web sites were also used to find relevant abstracts and documents.

RESULTS

Studies have revealed that with PMTCT, HIV transmission rate moved from 10.4% in 2006 to 0% in 2015. The PMTCT program remains the best way to care for HIV-infected pregnant women and their babies. The current PMTCT policy is based on evidence that male partner involvement is associated with women's completion of PMTCT.

CONCLUSION

This study shows that the reduction in mother to child transmission of HIV in Burkina-Faso over the years is mainly due to the improvement of PMTCT programs. Efforts still need to be made about the involvement of male partners.

Implementation and new insights in molecular diagnostics for HIV infection

INTRODUCTION

Acquired immunodeficiency syndrome (AIDS) is a kind of acquired disease that breaks down the immune system. Human immunodeficiency virus (HIV) is the causative agent of AIDS. By the end of 2016, there were 36.7 million people living with HIV worldwide. Early diagnosis can alert infected individuals to risk behaviors in order to control HIV transmission. Infected individuals are also benefited from proper treatment and management upon early diagnosis. Thanks to the public awareness of the disease, the annual increase of new HIV infections has been slowly declining over the past decades. The advent of molecular diagnostics has allowed early detection and better management of HIV infected patients. Areas covered: In this review, the authors summarized and discussed the current and future technologies in molecular diagnosis as well as the biomarkers developed for HIV infection. Expert Commentary: A simple and rapid detection of viral load is important for patients and doctors to monitor HIV progression and antiretroviral treatment efficiency. In the near future, it is expected that new technologies such as digital PCR and CRISPR-based technology will play more important role in HIV detection and patient management.

A cocktail of thermally stable, chemically synthesized capture agents for the efficient detection of anti-gp41 antibodies from human sera

We report on a method to improve in vitro diagnostic assays that detect immune response, with specific application to HIV-1. The inherent polyclonal diversity of the humoral immune response was addressed by using sequential in situ click chemistry to develop a cocktail of peptide-based capture agents, the components of which were raised against different, representative anti-HIV antibodies that bind to a conserved epitope of the HIV-1 envelope protein gp41. The cocktail was used to detect anti-HIV-1 antibodies from a panel of sera collected from HIV-positive patients, with improved signal-to-noise ratio relative to the gold standard commercial recombinant protein antigen. The capture agents were stable when stored as a powder for two months at temperatures close to 60(o)C.