9 Questions
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?
Previous exposure to other pathogens that induce protective cross-immunity
What is the potential reason for the low burden of COVID-19 in Africa compared to other continents?
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.
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?
Cross-reactive antibodies can interfere with serosurveillance and disease severity diagnosis, and could potentially offer some level of protection against SARS-CoV-2.
What was the aim of the study conducted in Zimbabwe?
To investigate pre-existing antibodies cross-reactive with SARS-CoV-2
What statistical software was used in the study to obtain Z scores for each population?
Statistical software (v.20.4.0).
What were the peptides reactive with IgG and IgM identified in the study?
Spike, nucleocapsid, and polyprotein 1AB proteins
What method did the study use to screen the serum samples for reactivity against the peptides from the proteomes of the seven human coronaviruses?
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.
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.
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
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