SARS-CoV-2 Virus and Antibodies
Coronaviruses (CoV) are a large family of viruses that cause illnesses ranging from the common cold to more severe diseases such as Middle East Respiratory Syndrome (MERS-CoV) and Severe Acute Respiratory Syndrome (SARS-CoV). The novel coronavirus, now known as the SARS-CoV-2, is a new strain that humans have not previously identified.
The core protein of SARS-CoV-2 is the N-protein (Nucleocapsid protein), a component located inside the virus. In the early days of the pandemic, detecting antibodies against the N-protein was used to diagnose COVID-19.
Vaccines developed to date focus on the S-Protein (Spike protein) as the target for the body to create antibodies against the SARS-Cov2 virus. Mutations of the SPIKE RNA are the signature cause of why most new variants of concern are more contagious. These mutations increase the viruses’ ability to connect to the ACE-2 Receptor of the human host. Naturally, without antibody intervention, the injected viral RNA can trigger a series of inflammatory reactions in the host, leading to the disease we know as COVID-19.
Antibodies Need to do Two Things to be Effective
Attach firmly to the virus S-protein, also called ‘avidity’.
Neutralize the impact of the virus by preventing RBD portion of the S-Protein from attaching to an ACE-2 receptor in the human host.
The Antibodies Production Process
When a natural SARS-CoV-2 virus invades the body, it causes an infection and multiplies. As the load of virus increases, the body detects the proteins of the virus, also know as antigens. The body mounts an immune response against the antigens by producing antibodies which neutralizes the impact of the virus.
The first type of antibodies created is called IgM. It appears early and wanes quickly. Think of IgM as the elite squad to get the infection quickly under control. This is followed by the IgG antibodies which develop later but are longer lasting. The latter is what we measure to determine recovery from a viral infection.