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Immune reactions caused by vaccination can help protect the body, or can sometimes make the condition worse. It is especially important now that multiple COVID-19 vaccines are in development. The best immunologists analyze the types of immune response to predict which type of vaccine would be the best.
The COVID-19 pandemic is still ongoing and is a huge challenge for healthcare professionals around the world.
Currently, there are several strategies to prevent the spread of the disease caused by the SARS-CoV-2 virus, including confinement or quarantine measures, social distancing, use of face masks and good hygiene, with frequent hand washing and application of antiseptics. . . However, it is clear that such restrictions affect our personal and professional lives.
That is why SARS-CoV-2 vaccines are being developed around the world, as vaccination could help stop the pandemic. But these vaccines can be designed in various ways, and immune responses can be different.
Recent work by scientists from the University of Sechenov and their Swiss colleagues looks at what type of immune reaction would be most favorable for the vaccine to be effective. The study has been published in International Archives of Allergy and Immunology.
The vaccine, as expected, should effectively induce high affinity neutralizing antibodies that would target SARS-CoV-2. At the same time, there is concern that infection after vaccination may lead to eosinophilic lung disease and eosinophil-associated Th2 immune potentiation.
Eosinophils are white blood cells involved in conditions such as bronchial asthma, eosinophilic esophagitis, and hypereosinophilic syndromes. Currently, despite the limited data available, there is no evidence that eosinophils play a protective or pathogenic role in COVID-19 infection.
However, eosinophils can still be involved when a person is vaccinated. For example, research on possible vaccines against SARS-CoV-1, a closely related virus that caused an epidemic in 2002-2004, showed that pulmonary eosinophilia was induced in ferrets, monkeys, and mice after viral exposure.
This fact suggests that SARS-CoV-2 vaccines could also cause similar immunopathology. Another source of complications could be the induced antibodies that promote viral uptake through the Fc receptors.
According to the study authors, the most advantageous strategy should focus on vaccines that induce the production of high-affinity virus-neutralizing antibodies.
These antibodies should block the interaction of SARS-CoV-2 with its cellular receptor, angiotensin converting enzyme 2 (ACE2). Successful vaccines are expected to polarize the T-cell response towards type 1 immunity and avoid stimulation of the cytokines that induce T-helper 2 immunity.
From our experience with the SARS-1 vaccine, we know that mice that received all of the spike protein (responsible for ACE2 binding) exhibited some eosinophilic complications due to Th-2 polarization of the immune response. “
Alexander Karaulov, study author and director of the Department of Clinical Immunology and Allergology at Sechenov University
“ At the same time, if the injected vaccine did not contain all of the spike protein, but rather its receptor-binding domain that is directly involved in interactions with ACE2, immune-mediated pathologies (hypereosinophilic syndrome) could be avoided due to high immunogenicity and high antibody titer. I think this is an important aspect, which continues to be little investigated ”.
The article is the result of a collaboration between Sechenov University and the University of Bern (Switzerland).
Source:
Magazine reference:
Simon H.-U., et al. (2020) Strategies to prevent SARS-CoV-2 mediated eosinophilic disease in association with vaccination and COVID-19 infection. International Archives of Allergy and Immunology. doi.org/10.1159/000509368.
