Immunity

Since the beginning of the COVID-19 pandemic, biomedical research has tried to better understand long-term immunity against SARS-CoV-2. At the beginning of infection, T-CD8 cells proliferate, and activate as effector cells upon contact with viral antigens, to eventually eliminate infected cells from the body. In the case of COVID-19, we do not understand their evolution, […]

Innate, or non-specific, immunity is one of the organism’s first lines of defence against pathogens. NK (Natural Killer) cells are one element of this immunity. These cells are lymphocytes which, unlike B and T lymphocytes in adaptive immunity, do not need to have had previous contact with the pathogen in order to become rapidly active […]

The type 1 interferon (IFN-I) plays an essential role in defending the organism against SARS-CoV-2. Treatment by IFN in serious cases of COVID-19 has been shown to be effective. Interferons are cytokines, small protein-messengers that orchestrate and regulate the immune response by activating it or slowing it down. The type 1 IFN is pro-inflammatory, that […]

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. […]

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 […]

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 […]

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, […]

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 […]

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. […]

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 […]