Combining SARS-CoV-2 interferon-gamma release assay with humoral response assessment to define immune memory profiles.

Objectives: In the post-SARS-CoV-2 pandemic era, "breakthrough infections" are still documented, due to variants of concerns (VoCs) emergence and waning humoral immunity. Despite widespread utilization, the definition of the anti-Spike (S) immunoglobulin-G (IgG) threshold to define protection has unveiled several limitations. Here, we explore the advantages of incorporating T-cell response assessment to enhance the definition of immune memory profile.

Specific detection of memory T-cells in COVID-19 patients using standardized whole-blood Interferon gammarelease assay.

Antigen-specific T-cells are essential for protective immunity against SARS-CoV-2. We set up a semi-automated whole-blood Interferon-gamma release assay (WB IGRA) to monitor the T-cell response after stimulation with SARS-CoV-2 peptide pools. We report that the WB IGRA is complementary to serological assays to assess SARS-CoV-2 immunity.

Deciphering Multifactorial Resistance Phenotypes in by Genomics and Targeted Label-free Proteomics.

Resistance to β-lactams in involves various mechanisms. To decipher them, whole genome sequencing (WGS) and real-time quantitative polymerase chain reaction (RT-qPCR) were complemented by mass spectrometry (MS) in selected reaction monitoring mode (SRM) in 39 clinical isolates. The targeted label-free proteomic approach enabled, in one hour and using a single method, the quantitative detection of 16 proteins associated with antibiotic resistance: eight acquired β-lactamases ( GES, NDM-1, OXA-23, OXA-24, OXA-58, PER, TEM-1, and VEB), two resident β-lactamases ( ADC and OXA-51-like) and six components of the two major efflux systems ( AdeABC and AdeIJK).

Expression, refolding and bio-structural analysis of a tetravalent recombinant dengue envelope domain III protein for serological diagnosis.

Dengue is a mosquito-borne disease caused by four genetically and serologically related viruses that affect several millions of people. Envelope domain III (EDIII) of the viral envelope protein contains dengue virus (DENV) type-specific and DENV complex-reactive antigenic sites. Here, we describe the expression in Escherichia coli, the refolding and bio-structural analysis of envelope domain III of the four dengue serotypes as a tetravalent dengue protein (EDIIIT2), generating an attractive diagnostic candidate.

Impact of Serum and Plasma Matrices on the Titration of Human Inflammatory Biomarkers Using Analytically Validated SRM Assays.

Protein biomarker discovery has inherent challenges linked to the validation of the analytical method used or to the impact of biological matrices. Matrix influences must be mastered to guarantee the reliability of the identified biomarkers to monitor human diseases. In this study, multiplexed mass spectrometry assays in selected reaction monitoring (SRM) mode have been developed to measure 107 inflammatory putative proteins in matched serum and plasma from 36 ICU trauma patients.

Clinical quantitation of prostate-specific antigen biomarker in the low nanogram/milliliter range by conventional bore liquid chromatography-tandem mass spectrometry (multiple reaction monitoring) coupling and correlation with ELISA tests.

Proteomics discovery leads to a list of potential protein biomarkers that have to be subsequently verified and validated with a statistically viable number of patients. Although the most sensitive, the development of an ELISA test is time-consuming when antibodies are not available and need to be conceived. Mass spectrometry analysis driven in quantitative multiple reaction monitoring mode is now appearing as a promising alternative to quantify proteins in biological fluids.

Mapping of B-cell epitopes in a Trypanosoma cruzi immunodominant antigen expressed in natural infections.

Tc40 is an immunodominant antigen present in natural Trypanosoma cruzi infections. This immunogen was thoroughly mapped by using overlapping amino acid sequences identified by gene cloning and chemical peptide synthesis. To map continuous epitopes of the Tc40 antigen, an epitope expression library was constructed and screened with sera from human chagasic patients.

Characterization of mimotopes mimicking an immunodominant conformational epitope on the hepatitis C virus NS3 helicase.

The hepatitis C virus (HCV) nonstructural 3 (NS3) protein is composed of an amino terminal protease and a carboxyl terminal RNA helicase. NS3 contains major antigenic epitopes. The antibody response to NS3 appears early in the course of infection and is focused on the helicase region.