Vaccines have played a crucial role in reducing morbidity and mortality caused by SARS-CoV-2. However, the emergence of new variants of the virus capable of evading the antibody response raises questions about the long-term effectiveness of this strategy. The research, published in the prestigious journal Nature Immunology, opens new perspectives on understanding the immune response against the virus, highlighting the fundamental role of T lymphocytes as a long-lasting defense weapon present in our body, beyond the response mediated by antibodies.
I study
The researchers employed several mouse models, including mice lacking antibodies but with intact lymphocyte function and an innovative model expressing a hybrid human/mouse ACE2 receptor. The study was coordinated by Professor Matteo Iannacone, director of the Division of Immunology, Transplants and Infectious Diseases of the IRCCS San Raffaele Hospital and professor of General Pathology at the Vita-Salute San Raffaele University, and carried out in collaboration with professors Luca Guidotti, deputy scientific director and professor of General Pathology at the IRCCS San Raffaele Hospital and Vita-Salute San Raffaele University, Marco Bianchi, head of the chromatin dynamics unit of the IRCCS San Raffaele Hospital and Professor of Molecular Biology at the Vita-Salute University San Raffaele, and Raffaele De Francesco, head of the Virology laboratory at the National Institute of Molecular Genetics and Professor of Microbiology at the University of Milan.
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The immune system
When our immune system is hit by an infection, it implements various defense mechanisms, including the activation of B lymphocytes, responsible for producing antibodies, and the activation of T lymphocytes, which coordinate the entire immune system , defeating cells identified as “foreign” and therefore potentially harmful.
“Our research has revealed that T lymphocytes, thanks to their historical memory, are able to provide protection against the SARS-CoV-2 virus even when antibodies are not present. This form of defense, independent of antibodies, underlines the crucial significance of the T-cell-mediated cellular response in the fight against the virus,” says the professor Matteo Iannacone.
“We have observed how a certain subgroup of T lymphocytes, called CD8+, are crucial in combating serious infections, while the so-called CD4+ T lymphocytes play a complementary role in milder infections, with a significant role played by interferon-gamma (IFN-) “, adds Valeria Fumagalli, researcher in Iannacone’s laboratory, first author of the study, and beneficiary of specific funding from the Prossimo Mio Foundation in Milan.
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Defending yourself from Covid
So far, the defense strategy against SARS-CoV-2 has mainly emphasized the antibody response, assuming that the antibody-mediated response was the main, if not the only, mechanism of protection after vaccination or contact with the virus. “The results of our study change the traditional understanding of immunity and demonstrate the importance of including the T cell-mediated immune response in monitoring responses to vaccinations and in new vaccine development strategies,” emphasizes Professor Iannacone.
The vaccines
“The indication for vaccination remains the fundamental piece to protect the population from serious disease, and our research demonstrates the effectiveness of this approach also for protection against reinfections caused by viral variants”. “This work highlights the importance of an approach to immunity against SARS-CoV-2 that considers both the antibody and cellular responses. Our research paves the way for new vaccination and therapeutic strategies for effective and long-lasting protection against the virus and its emerging variants,” adds Professor Iannacone.
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“The study was possible thanks to the continuous support of the SAME Foundation, a philanthropic body of the Same Deutz Fahr group, of Treviglio”, highlights the professor Luca Guidotti. SAME Foundation has allowed the creation and setup of BSL3 biosafety environments – unique in their kind in Italy – at the IRCCS San Raffaele Hospital: “thanks to the various advanced technologies dedicated to the study of highly dangerous respiratory viruses in mouse models, These environments have allowed and continue to allow the conduct of high-precision research on SARS-CoV-2, continues Guidotti. Among the innovative research tools used in this project, thanks to donations, there is also an inhalation tower that allows the models to be exhibited mice to viral particles, infecting them in a physiological way, through exposure to SARS-CoV-2 aerosolized at pressure, temperature and humidity. “The support of the SAME Foundation is yet another example of how scientific research in Italy benefits enormously from philanthropic activities of great impact”, concludes Professor Guidotti.
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– 2024-03-15 13:35:45
