A Biochemiluminescent Assay for Rapid Diagnosis of Influenza

Background: A biochemiluminescent assay of influenza diagnosis is presented. The assay diagnoses influenza based on detection of the influenza viral neuraminidase activity. An instrument designed for the assay is also reported. This assay solves the problem that current influenza virus diagnosis assays are susceptible to virus mutation. Methods: A luciferase-based complex is synthesized as biochemiluminescent substrate. The substrate is cleaved to free luciferin with presence of influenza neuraminidase in specimen. Luciferase is oxidized to oxyluciferin with luciferin as catalyzer resulting in luminescence, which is proportional to the neuraminidase activity and measured by instrument. The instrument uses a photomultiplier tube (PMT) as sensor, with 24 test channels. Fine optical arrangements enable the instrument with high sensitive and accuracy. Results: A total of 389 clinical specimens were collected to evaluate the performance of the assay in clinical settings. This assay had a sensitivity and specificity of 95.92% (95% confidence interval: 91.38%-98.12%) and 97.93% (95% confidence interval: 95.26%-99.11%), respectively, compared to the colloidal gold assay. Conclusion: As a biochemiluminscence assay, this assay is advantageous in sensitivity and specificify. It does not require any washing and separation steps, which makes the instrument simple in design and easy to operate or maintenance. The assay is suitable for the rapid diagnosis of influenza virus in POC settings.

Viral Antibody in Saliva Based Diagnostics: A Systematic Review

Background: Salivary viral antibodies originated either from viral salivary gland infection or systemic diseases. Virus related antibodies in saliva are essential for the virus diagnosis and the leveragial measurement of viral infection. Objectives: This review aims to evaluate the general characteristics of salivary protein; the available knowledge on viral antibodies in saliva, the current progress of proteomic studies on salivary viral antibodies, and salivary antibody-based diagnosis methods for viral infection. Method: Searching articles carried out with the help of PubMed dan Science Direct. Then, the relevant articles screened accordingly. Result: Protein is the most abundant biomolecules in saliva, more than nucleic acids. The salivary protein composition is quite complicated. Salivary proteins are originated from the mouth tissues, microbiota, secretes of salivary glands, and antibodies, especially virus-induced antibodies—these virus antibodies found in saliva. There is a relationship between the infectious virus species with the salivary antibodies. Proteomic studies are fundamental for viral detection method, but they are not yet much carried out. The conventional diagnosis for a viral infection is relay on PCR-based methods. New promising practices, besides the proteomic approach, are nano biosensor and SERS (Raman Spectrometry). Conclusions: As part of a salivary protein, salivary viral antibodies have a very specify interaction with viral antigens. Information on the antibody as protein needs to be enriched by the proteomic studies. Further accuracy and specificity of salivary virus diagnosis methods depend on the progress of proteomic studies of salivary antibodies.

Comparison of IgG and neutralizing antibody responses after one or two doses of COVID-19 mRNA vaccine in previously infected and uninfected persons

ABSTRACTObjectiveTo compare anti-SARS-CoV-2 spike receptor binding domain (RBD) IgG antibody concentrations and antibody-mediated neutralization of spike-ACE2 receptor binding in vitro following vaccination of non-hospitalized participants by sero-status and acute virus diagnosis history.MethodsParticipants were studied before and after mRNA vaccination in a community-based, home-collected, longitudinal serosurvey; none reported hospitalization for COVID-19. Prior to vaccination, some reported prior positive acute viral diagnostic testing and were seropositive (COVID-19+). Participants who did not report acute viral diagnostic testing were categorized as seropositive or seronegative based on anti-spike RBD IgG test results. Primary measures were anti-spike RBD IgG concentration and percent antibody-mediated neutralization of spike protein-ACE2 interaction prior to vaccination, and after one or two doses of vaccine.ResultsOf 290 unique vaccine recipients, 42 reported a prior COVID-19 diagnosis and were seropositive (COVID-19+). Of the 248 with no history of acute viral diagnostic testing, 105 were seropositive and 143 seronegative before vaccination. The median age was 38yrs (range 21-83) with 65% female and 35% male; 40% were non-white. Responses were evaluated after one (n=140) or two (n=170) doses of BNT162b2/Pfizer or mRNA-1273/Moderna vaccine. After one dose, median post-vaccine IgG concentration and percent neutralization were each significantly higher among the COVID-19+ group (median 47.7 µg/ml, IgG; >99.9% neutralization) compared to the seropositives (3.4 µg /ml IgG; 62.8% neutralization) and seronegatives (2.2 µg /ml IgG; 39.5% neutralization). The latter two groups reached >95% neutralization after the second vaccine dose.ConclusionsA prior outpatient COVID-19 diagnosis was associated with strong anti-spike RBD IgG and in vitro neutralizing responses after one vaccine dose. Persons seropositive for anti-spike RBD IgG in the absence of acute viral diagnostic testing, and those who were seronegative, required two doses to achieve equivalently high levels of IgG and neutralization activity. One mRNA vaccine dose is not sufficient to generate in vitro evidence of strong protection against COVID-19 among most persons previously infected with SARS-CoV-2, nor among seronegative persons.

AMLO virus diagnosis raises Mexico minister concerns

Headline MEXICO: AMLO virus diagnosis raises minister concerns