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Questions and Answers
What is the potential impact of pre-existing cross-reactive antibodies on SARS-CoV-2 serosurveillance and disease diagnosis?
Pre-existing cross-reactive antibodies can interfere with serosurveillance and disease severity diagnosis.
What percentage of pre-pandemic serum samples from Zimbabwean adults have been found to have pre-existing antibodies that cross-react with SARS-CoV-2?
32%.
What is the potential reason for the low burden of COVID-19 in Africa compared to other continents?
What is the potential reason for the low burden of COVID-19 in Africa compared to other continents?
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Why is it important to consider cross-reactive antibodies when interpreting SARS-CoV-2 seroepidemiology studies and evaluating outcomes of COVID-19 vaccine trials in Africa?
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What was the aim of the study conducted in Zimbabwe?
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What statistical software was used in the study to obtain Z scores for each population?
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What were the peptides reactive with IgG and IgM identified in the study?
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What method did the study use to screen the serum samples for reactivity against the peptides from the proteomes of the seven human coronaviruses?
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Study Notes
- Pre-existing antibodies that cross-react with SARS-CoV-2 have been found in 32% of pre-pandemic serum samples from Zimbabwean adults.
- These cross-reactive antibodies can interfere with serosurveillance and disease severity diagnosis.
- The antibodies could potentially offer some level of protection against SARS-CoV-2.
- The low burden of COVID-19 in Africa compared to other continents could be due to previous exposure to other pathogens that induce protective cross-immunity.
- Cross-reactive antibodies should be considered when interpreting SARS-CoV-2 seroepidemiology studies and evaluating outcomes of COVID-19 vaccine trials in Africa.
- There are seven types of coronaviruses that naturally infect humans.
- The common cold viruses have low pathogenicity while SARS and MERS coronaviruses can cause severe respiratory illness.
- The study calls for further characterisation of SARs-CoV-2 immune phenotypes and responses in African populations.
- Antibodies for other coronaviruses have been shown to last as long as 34 months.
- There is potential for pre-existing natural IgM antibodies being protective against infection.
- A study aimed to identify pre-existing antibodies that cross-react with peptides from all seven human coronaviruses in serum samples collected from a cross-section of Zimbabweans before the SARS-CoV-2 pandemic in November 2019.
- The study aimed to determine the peptide epitopes of all proteins from the seven coronaviruses reactive with pre-SARS CoV-2 serum samples collected from Zimbabwe covering a period of 19 years between 2000 and 2019.
- The study aimed to determine the potential antigenic sources that stimulated cross-reactivity with the SARS-CoV-2 peptide epitopes in the pre-SARS-CoV-2 serum samples.
- The study used a PEPperCHIP Coronavirus Discovery Microarray to screen the serum samples for reactivity against the peptides from the proteomes of the seven human coronaviruses.
- The test detects the presence of IgM and IgG antibodies directed against the nucleocapsid and the spike proteins of the SARS-CoV-2 virus.
- The manufacturer indicated that the test had a clinical sensitivity of over 98% for SARS-CoV-2 infection.
- The study found that the numbers of COVID-19 cases and deaths in Africa have been less than that in other continents.
- The study identified conserved regions between peptides reactive with the serum samples and known B-cell epitopes from other immunogens (pathogens, allergens, and autoantigens).
- The study used statistical software (v.20.4.0) to obtain Z scores for each population.
- The study had ethical approval for the parent study.
- A study was conducted in Zimbabwe to investigate pre-existing antibodies cross-reactive with SARS-CoV-2.
- 339 pre-pandemic serum samples were collected in November 2019 from two rural villages in northeastern Zimbabwe.
- The samples were cross-reactive with SARS-CoV-2 antigens on antibody-based COVID-19 rapid diagnostic tests (RDTs).
- The study identified peptides on human coronaviruses that these antibodies were cross-reactive with.
- The most reactive samples across all the samples were from an 11-year-old individual collected in 2006.
- IgM in serum across all the Zimbabwean samples tended to recognise peptides with a high frequency of lysine.
- The IgG responses were generally lower than IgM responses.
- The study found that antibodies cross-reactive with SARS-CoV-2 peptides had been stimulated by antigens or immunogens from other sources, potentially other coronaviruses and autoantigens.
- The study obtained ethical approval from the Medical Research Council of Zimbabwe and the Scotland A Research Ethics Committee.
- The study used a positive control sample from a convalescent adult male in the UK with a high IgG titre against SARS-CoV-2 S1 spike protein and the nucleocapsid protein.
- Study analyzed serum samples from Zimbabwe for reactivity to SARS-CoV-2 proteins.
- Peptides reactive with IgG and IgM were identified in spike, nucleocapsid, and polyprotein 1AB proteins.
- Some peptides shared partial sequences with other known B-cell antigens from other pathogens.
- Spike protein had the least number of peptides with homologous motifs to non-SARS-CoV-2 proteins.
- Nucleocapsid protein peptides shared motifs with nucleocapsid protein peptides from other betacoronaviruses, especially SARS-CoV and MERS-CoV.
- Polyprotein 1AB peptides shared motifs with various human autoantigens, chaperone proteins, and allergens.
- Some peptides shared motifs with human autoantigens and pathogens occurring in Zimbabwe, such as human betaherpes virus 6B and influenza A virus.
- Several redundant peptides in the spike, polyprotein 1AB, and nucleocapsid proteins were shared with other betacoronaviruses and, to a lesser extent, alphacoronaviruses.
- Similarities were found to pathogens that have not been reported in Zimbabwe including pangolin coronavirus, Trypanosoma cruzi, and Onchocerca volvulus.
- The study provides insights into the immune response to SARS-CoV-2 in Zimbabwe and potential cross-reactivity with other pathogens.
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Description
Test your knowledge about pre-existing antibodies cross-reactive with SARS-CoV-2 discovered in Zimbabwean adults with this informative quiz. Learn about the potential implications of these antibodies for serosurveillance and COVID-19 vaccine trials in Africa, and the possible protective effects of pre-existing antibodies against the virus. Explore the characteristics of the seven types of coronaviruses that naturally infect humans, and the cross-reactivity of antibodies to these viruses. Discover the peptide epitopes of all proteins from the
