The variability of the serological response to SARS‐corona virus‐2: Potential resolution of ambiguity through determination of avidity (functional affinity)

Abstract

Data on the serological response towards SARS CoV‐2 in 16 recent reports were analyzed and a high degree of variability was shown. IgM responses were either found earlier than IgG, or together with IgG, later than IgG or were missing. Therefore, clear distinctions between early, intermediate and past infections are obviously not possible merely on the basis of IgM and IgG determinations. The review of publications on the serology of other virus groups shows that variable IgM responses can be found as well and therefore are not specific for SARS CoV‐2 infections. A model to explain this variability is proposed. The inclusion of avidity determination into regular diagnostic procedures has allowed to resolve such “atypical” serological constellations. The potential use of avidity determination for the diagnosis of Covid‐19, for risk assessment, epidemiological studies, analysis of cross reactions, as well as for the control of vaccination programs is suggested and discussed. This article is protected by copyright. All rights reserved.

Quantification of antibody avidities and accurate detection of SARS-CoV-2 antibodies in serum and saliva on plasmonic substrates

“…In the current case, testing of a large number of samples from patients recovered from COVID-19 over long periods of time (>6 months to years) is needed to glean a full picture of antibody maturation. The SARS-CoV-2 antibody-avidity index is expected to increase due to its similarity to SARS 24,49 , for which significant increase in antibody avidity over time (more than about six months, up to 269 days) 49 was observed. The same phenomenon was also noticed for the four common human coronaviruses OC43, HKU1, NL63 and 229E, for which the pGOLD assay indeed detected high antibody avidity, given that most adults have had common colds in the past.…”

“…Highly specific antibody tests are critical to avoid misinterpretations or false positives, unnecessary stress and quarantine, and to prevent controversies and wrong conclusions for surveillance or prevalence studies [17][18][19][20][21][22][23] . On the other hand, no antibody-avidity test [24][25][26][27][28][29][30] currently exists for COVID-19 to assess antibody maturation and distinguish recent versus old infections. Also, no SARS-CoV-2 antibody test currently offers testing of non-invasive matrices such as saliva, which could facilitate population-based mass screening of COVID-19.…”

A multi-target lateral flow immunoassay enabling the specific and sensitive detection of total antibodies to SARS COV-2

“…The nucleocapsid protein of SARS-related virus has high immunogenic activity and is abundantly overexpressed during infection. In fact, several serological assays for detecting SARS CoV-2 antibodies employ the N protein as the antigen [ [12] , [13] , [14] ]. In addition, antibodies towards N have been shown to be able to neutralize the virus, with an excellent correlation between the existence of anti-N antibodies and the neutralizing ability of the serum [ 10 , 15 ].…”

SARS-CoV-2 structural coverage map reveals state changes that disrupt host immunity

“…The top ranked helicase was IGHMBP2 (a.k.a. SMBP2), which interacts with single-stranded DNA in the class switching region of the genome (Yu et al, 2011), close to IGMH (the gene coding the constant region of immunoglobulin heavy chains); we speculate that mimicry of IGHMBP2 may explain the dysregulation of immunoglobulin-class switching observed clinically (Bauer, 2020). The second ranked helicase was UPF1 (a.k.a.…”