The carefully orchestrated dance between the immune system and the viral proteins that induce immunity to COVID-19 may be more complex than previously thought. A new study by researchers at Brigham and Women Hospital used a single-molecule ultrasound (Simoa) to detect extremely low levels of molecules in the blood and measured how those levels change during the days and weeks after vaccination. The team found evidence of SARS-CoV-2 circulating protein subunits, followed by evidence that the body increases its immune response and then cleanses the viral protein below the detection level of a single molecule. . The results are published in Clinical infectious diseases.
“Because of our ultra-sensitive method, we can corroborate that the mRNA vaccine works as intended, eliciting the body’s immune response,” said David Walt, Ph.D., corresponding author, faculty member of the Brigham Department of Pathology. Walt is also a member of the Wyss Institute and is a professor at the Howard Hughes Medical Institute. “We were able to detect extremely low levels of virus protein and see that as soon as the body begins to generate antibodies, these levels have decreased until they are undetectable. “Walt has a financial interest in Quanterix Corporation, the company that developed the ultra-sensitive digital immunoassay platform used in this work.
To conduct their study, Walt and colleagues measured the levels of SARS-CoV-2 protein subunits in plasma samples collected from 13 participants who received two doses of the Modern vaccine (mRNA-1273). Specifically, the team measured SARS-CoV-2 Spike, S1, and Nucleocapsid antigen levels. The team examined the collected plasma at 10-13 time points between 1 and 29 days after the first injection and 1-28 days after the second injection. The mean age of the participants was 24 and the percentage of women was 46.
The team found that 11 of 13 participants had low levels of SARS-CoV-2 protein (S1 subunit) as early as one day after vaccination. The protein level of the S1 subunit reached its maximum on average five days after the first injection. In all participants, the S1 protein level decreased and became undetectable on day 14. Spike protein was detected in 3 of 13 participants an average of 15 days after the first injection. After the second dose of vaccine, no S1 or Spike was detected.
The team collected the corresponding antibody data and showed that the immune response began to increase after the production of the viral proteins. Increased levels of antibodies correlated with viral protein plasma clearance.
The researchers note that the level of translated protein detected was extremely low and disappeared once the antibodies were detected. All study participants were healthy volunteers who were vaccinated but not infected with SARS-CoV-2.
“The vaccine is designed to introduce mRNA into the body, which is then translated into the Spike protein. It is the Spike protein that can activate the immune system, which in turn creates antibodies to prevent future infections, “said co-author Alana Ogata, Ph.D., a postdoctoral fellow in Walt’s lab.” We noticed that antibodies targeting Spike and S1 proteins are generated only 1-2 days after S1 circulation is detected, followed by protein removal. In addition, we see that the second dose does not lead to the circulation of proteins, but it does provide an additional increase in antibody levels, as expected. “
The researchers point out that the limitations of the current study include the small sample size and possible biases arising from the enrollment of healthy young adults, who may not be representative of the general population. The research team plans to continue its plasma studies in other populations, including pregnant women and children, to better understand the dynamics between viral proteins and immune response.
Alana F Ogata et al, circulating SARS-CoV-2 vaccine antigen detected in plasma of mRNA-1273 vaccine receptors, Clinical infectious diseases (2021). DOI: 10.1093 / cid / ciab465
Brigham and Women Hospital
Citation: An ultrasensitive blood test detects viral protein, confirms that the vaccine activates a robust immune response (2021, May 26) recovered on May 26, 2021 at https://medicalxpress.com/news/2021-05-ultrasensitive- blood-viral-protein-vaccine.html
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