Pre-analytical considerations in the development of a prototype SARS-CoV-2 antigen ARCHITECT automated immunoassay.

OBJECTIVES: To evaluate pre-analytical challenges related to high-volume central laboratory SARS-CoV-2 antigen testing with a prototype qualitative SARS-CoV-2 antigen immunoassay run on the automated Abbott ARCHITECT instrument. METHODS: Contrived positive and negative specimens and de-identified nasal and nasopharyngeal specimens in transport media were used to evaluate specimen and reagent on-board stability, assay analytical performance and interference, and clinical performance. RESULTS: TCID50/mL values were similar for specimens in various transport media. Inactivated positive clinical specimens and viral lysate (USA-WA1/2020) were positive on the prototype immunoassay. Within-laboratory imprecision was ≤0.10 SD (<1.00 S/C) with a ≤10% CV (≥1.00 S/C). Assay reagents were stable on board the instrument for 14 days. No high-dose hook effect was observed with a SARS-CoV-2 stock of Ct 13.0 (RLU>1.0 × 106). No interference was observed from mucin, whole blood, 12 drugs, and more than 20 cross-reactants. While specimen stability was limited at room temperature for specimens with or without viral inactivation, a single freeze/thaw cycle or long-term storage (>30 days) at -20 °C did not adversely impact specimen stability or assay performance. Specificity of the prototype SARS-CoV-2 antigen immunoassay was ≥98.5% and sensitivity was ≥89.5% across two ARCHITECT instruments. Assay sensitivity was inversely correlated with Ct and was similar to that reported for the Roche Elecsys® SARS-CoV-2 Ag immunoassay. CONCLUSIONS: The prototype SARS-CoV-2 antigen ARCHITECT immunoassay is sensitive and specific for detection of SARS-CoV-2 in nasal and nasopharyngeal specimens. Endogenous proteases in mucus may degrade the target antigen, which limits specimen storage and transport times and complicates assay workflow.

Development of a new automated IL-6 immunoassay.

OBJECTIVES: Quantitative detection of interleukin-6 (IL-6) in serum and plasma can help monitor immune responses and the development of acute inflammation to guide patient management. We developed an IL-6 immunoassay for use with the automated ARCHITECT system for detecting an increase in the inflammatory response. METHODS: Immunized mouse sera were tested and selected B-cells were harvested for fusion with myeloma cells. A panel of monoclonal antibodies were produced, from which capture and detection monoclonal antibodies for the prototype IL-6 immunoassay were selected and screened on the ARCHITECT instrument. The antibody pair that most effectively captured and detected IL-6 was selected to develop a prototype IL-6 immunoassay. Calibrator and panel preparations using an internal recombinant IL-6 standard were compared to serum panels prepared with the IL-6 International Standard 89/548. Assay specificity and spike recovery were determined, and assay sensitivity was compared with the Roche EUA Elecsys IL-6 assay run on the cobas analyzer. RESULTS: Twenty-one antibodies in 441 antibody pairs were screened. The prototype IL-6 assay showed high sensitivity with an estimated limit of detection of 0.317 pg/mL and limit of quantitation of <1.27. Spike recovery was 90%-110% in serum and plasma. The internal recombinant human IL-6 calibrator showed excellent stability for 63 days at 2-8 °C. The prototype IL-6 immunoassay was specific for IL-6, exhibited no cross reactivity to related cytokines and interleukins, and was 10-fold more sensitive than the Elecsys IL-6 assay. CONCLUSIONS: The prototype ARCHITECT IL-6 automated immunoassay is a reliable and robust method for the quantitative determination of IL-6 in human serum and plasma.

Tergitol-15-S-9 inactivates SARS-CoV-2 and boosts immunoassay signals.

Inactivation of SARS-CoV-2 virus is necessary to mitigate risk but may interfere with diagnostic assay performance. We examined the effect of heat inactivation on a prototype SARS-CoV-2 antigen immunoassay run on the ARCHITECT automated analyzer. Recombinant full-length SARS-CoV-2 nucleocapsid protein and virus lysate detection was reduced by 66 and 31%, respectively. Several nonionic detergents were assessed as inactivation alternatives based on infectivity in cultured Vero CCL81 cells. Incubation of SARS-CoV-2 in 0.1% Tergitol 15-S-9 for 10 min significantly reduced infectivity and increased the immunoassay signal for cultured lysate and patient specimens. Tergitol 15-S-9 can inactivate SARS-CoV-2 while preserving epitopes on the nucleocapsid protein for enhanced detection by immunoassay antibodies.

[RISK ASSESSMENT FOR AEROSOL INFECTION BY THE NEW CORONA VIRUS AND PROTECTION BY RESPIRATORS].

INTRODUCTION: SARS-CoV-2 is dispersed from patients by talking, coughing and sneezing. The generated micro-droplets aerosols can travel up to 8 meters, stay suspended for long periods and preserve viral infectivity for a median of 2.7 hours. An unprotected person exposed to this cloud, might inhale a considerable amount of infectious viral doses, which will attach to the ACE 2 receptors on alveoli epithelium, resulting in infection. N95 respirators and surgical masks block 95% and 50-60% respectively of inhalable particles and protect the wearer from infection. Surgical masks and N95 without exhalation valve, protect both the wearer and the environment from carriers and sick people.

Intermediate filament aggregates cause mitochondrial dysmotility and increase energy demands in giant axonal neuropathy.

Intermediate filaments (IFs) are cytoskeletal polymers that extend from the nucleus to the cell membrane, giving cells their shape and form. Abnormal accumulation of IFs is involved in the pathogenesis of number neurodegenerative diseases, but none as clearly as giant axonal neuropathy (GAN), a ravaging disease caused by mutations in GAN, encoding gigaxonin. Patients display early and severe degeneration of the peripheral nervous system along with IF accumulation, but it has been difficult to link GAN mutations to any particular dysfunction, in part because GAN null mice have a very mild phenotype. We therefore established a robust dorsal root ganglion neuronal model that mirrors key cellular events underlying GAN. We demonstrate that gigaxonin is crucial for ubiquitin-proteasomal degradation of neuronal IF. Moreover, IF accumulation impairs mitochondrial motility and is associated with metabolic and oxidative stress. These results have implications for other neurological disorders whose pathology includes IF accumulation.

Some like it hot: The emerging role of spicy food (capsaicin) in autoimmune diseases.

Autoimmune diseases refer to a spectrum of diseases characterized by an active immune response against the host, which frequently involves increased autoantibody production. The pathogenesis of autoimmune diseases is multifactorial and the exploitation of novel effective treatment is urgent. Capsaicin is a nutritional factor, the active component of chili peppers, which is responsible for the pungent component of chili pepper. As a stimuli, capsaicin selectively activate transient receptor potential vanilloid subfamily 1(TRPV1) and exert various biological effects. This review discusses the effect of capsaicin through its receptor on the development and modulation of autoimmune diseases, which may shed light upon potential therapies in capsaicin-targeted approaches.

[The sick building syndrome as a part of 'ASIA' (autoimmune/auto-inflammatory syndrome induced by adjuvants)].

The entity 'sick building syndrome' is poorly defined and comprises of a set of symptoms resulting from environmental exposure to a work or a living environment. The symptoms are mainly "allergic"-like and include nasal, eye, and mucous membrane irritation, dry skin as well as respiratory symptoms and general symptoms such as fatigue, lethargy, headaches and fever. The Autoimmune [Auto-inflammatory] Syndrome Induced by Adjuvants (ASIA) is a wider term which describes the role of various environmental factors in the pathogenesis of immune mediated diseases. Factors entailing an immune adjuvant activity such as infectious agents, silicone, aluminium salts and others were found in association with defined and non-defined immune mediated diseases. The sick building syndrome and ASIA share a similar complex of signs and symptoms and probably the same immunological mechanisms which further support a common denominator.

Sequence composition of disordered regions fine-tunes protein half-life.

The proteasome controls the concentrations of most proteins in eukaryotic cells. It recognizes its protein substrates through ubiquitin tags and initiates degradation at disordered regions within the substrate. Here we show that the proteasome has pronounced preferences for the amino acid sequence of the regions at which it initiates degradation. Specifically, proteins in which the initiation regions have biased amino acid compositions show longer half-lives in yeast than proteins with unbiased sequences in the regions. The relationship is also observed on a genomic scale in mouse cells. These preferences affect the degradation rates of proteins in vitro, can explain the unexpected stability of natural proteins in yeast and may affect the accumulation of toxic proteins in disease. We propose that the proteasome's sequence preferences provide a second component to the degradation code and may fine-tune protein half-life in cells.

[A hantavirus killed an Israeli researcher: hazards while working with wild animals].

An Israeli researcher working in Finland with Bank Voles, contracted an infectious viral disease and died. This was a rare event, but it is important to learn about this class of viruses and to be aware of the hazards while working in the field in close contact with wild animals. The virus termed Puumala belongs to the genus Hanta from the Bunyaviridae family. The natural reservoir is rodents, mice, rats and Bank Votes for the Puuamala strain. The disease is termed HFRS (hemorrhagic fever with renal syndrome), is prevalent in Asia and Europe, affecting 200,000 people a year, with 5-15% percent mortality (although in Finland mortality rate is 0.1%). The New World strains cause HPS (hemorrhagic pulmonary syndrome) affecting 200 people a year with 40% mortality. Virus is present in all rodents excretions, and route of infection is by aerosols, hand to mucus membranes contamination, by rodents bites and by contaminated food or water. More than 226 work related infections were documented. Treatment with Ribavirin helps in HFRS but not in HPS. The virus is stable in the environment for long periods, and research must be carried out at biosafety level 3. Working outdoors in rodent infested area, should be carried out using protective clothing, gloves, googles and face mask whenever aerosol producing tasks are performed. Both indoor and outdoor, it is important to adhere to self-hygienic procedures, especially hand washing.

Lysine residues at the first and second KTKEGV repeats mediate α-Synuclein binding to membrane phospholipids.

While α-Synuclein (α-Syn) is mainly detected as a cytosolic protein, a portion of it is recovered bound to membranes. It is suggested that binding to membrane phospholipids controls α-Syn structure, physiology and pathogenesis. We aimed at investigating the role, of the positive charged lysine residues at the KTKEGV repeat motif, in mediating α-Syn associations with membrane phospholipids and in α-Syn oligomerization and aggregation. Specifically, two positive lysine (K) residues were replaced with two negative glutamic acid (E) residues at either the first or second KTKEGV repeat motifs. The effect of these mutations on membrane binding was determined by a quantitative phospholipid ELISA assay and compared to wild-type α-Syn and to the Parkinson's disease-causing mutations, A30P, E46K and A53T. We found that the K to E substitutions affected α-Syn binding to phospholipids. In addition, K to E substitutions resulted in a dramatically lower level of soluble α-Syn oligomers and larger intracellular inclusions. Together, our results suggest a critical role for lysine residues at the N-terminal repeat domain in the pathophysiology of α-Syn.