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Popularization of research advances on COVID-19

Immunity

What type of immunity is the most effective?

Acquiring effective immunity is a key element in our fight against the virus. Good immunity gives robust and durable protection. However, there are two types of adaptive immunity against SARS-CoV-2: the first is natural immunity, acquired when infection with the virus takes place, and the other is vaccinal immunity. Their effect may even be cumulative. […]

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CD4 T lymphocytes from endemic coronaviruses could activate

SARS-CoV-2 has numerous similarities with endemic human coronaviruses (HCoV), which cause common infections. Several studies suggest that anti-HCoV immunity exists, capable of combatting SARS-CoV-2, although its role in the physiopathology of COVID-19 is unclear. This cross-immunity is hotly debated, but in the light of its importance for vaccination, it is crucial to better understand its […]

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Antibodies strengthen during convalescence

Neutralising antibodies produced as a result of infection or vaccination are an essential part of antiviral immunity. When SARS-CoV-2 infection occurs, the main target of neutralising antibodies is the RBD (Receptor Binding Domain) of the viral spike protein. The RBD is the region in contact with the ACE2 cellular receptor that enables entry of the […]

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A more effective antibody that targets a stable region of the spike

Coronaviruses are zoonotic pathogens (deriving from animals) which have caused various pandemics over the last 20 years. The 3 most pathogenic coronaviruses for humans belong to the class of β-coronaviruses: SARS-CoV-2, SARS-CoV and MERS-CoV. The spike surface protein (S)  of these coronaviruses enables entry of the virus into the cell. The S1 sub-unit of S, […]

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Are variants neutralised by antibody responses?

The emergence of variants of concern (VOC), different to the original Wuhan strain from both antigenic and functional points of view, call into question the efficacy of current vaccines, since they may be able to evade neutralising antibodies (nAbs). In particular, the Alpha (⍺) or UK variant, the Gamma (ɣ) or Brazilian variant, the Beta […]

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Antibodies that are effective against variants

The SARS-CoV-2 variants of concern (VOC) are more transmissible, potentially more virulent, and capable of escaping neutralising antibodies (nAbs), whether they are therapeutic or induced by natural infection or by vaccination. The spike governs viral entry, and is composed, amongst other elements, of the RBD (receptor binding domain), which interacts with the human ACE2 receptor. […]

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Defective immunity of the nasal mucosa may result in severe cases

Like other respiratory viruses, SARS-CoV-2 multiplies initially in the nasopharynx, which facilitates its transmission. However, certain patients develop an infection in the lower respiratory passages where a combination of inflammatory and viral processes may lead to severe cases of COVID-19. However, the first cellular targets of the virus and the consequences of infection on the […]

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Can some antibodies make the illness worse?

Used as prevention or therapy, neutralising antibodies (NAbs) can help control the COVID-19 pandemic. They mainly target the RBD (Receptor Binding Domain) of the spike viral protein, thus blocking entry of the virus into the target cell. But certain NAbs, less powerful, also target the NTD (N-Terminal Domain). Conversely, certain so-called “facilitating” antibodies are able […]

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Analysis of the CD4 T lymphocyte response

As well as humoral immunity (antibody immunity), which plays an essential role against viral infection, cellular immunity (T lymphocytes) is also very important. Lymphocytes are made up of B lymphocytes, which produce antibodies; CD8 T lymphocytes, often called cytotoxic T lymphocytes, which destroy infected cells; and CD4 T lymphocytes, known as helpers. The T CD4 […]

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Assessment of antibody responses against SARS-CoV-2

The rapid spread of SARS-CoV-2 can be attributed to the fact that the world’s population was for the most part immunologically naïve. Although we have learned to better understand the virus, many questions remain unanswered. What we know today is that 4 endemic human coronaviruses (HCoVs: alpha- and beta-coronaviruses, NL63, 229E) cause respiratory infections that […]

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