A virus a pathogen normally debated as non-living
but still has the capability to threaten
the existence of humanity as we know it.
A new virus SARS-CoV-2 has introduced itself and
causes the disease we all know as COVID19.
This a new strand of coronavirus first discovered
in Wuhan, Hubei province of China, and I will
be discussing the immunology behind this virus,
let's dive in: When the virus enters the body, it travels from its point
of entry to its target organs such as the
spleen, intestines or lungs where it has the
worst effect. Upon reaching the lungs
The virus connects to a specific receptor
on the type 2 pneumocytes in the alveoli called
the ACE2 receptor allowing it to inject its
genetic material (RNA) or be swallowed into
the cell, this is called Receptor-mediated
endocytosis.
Once inside the cell, the virus uses its mechanisms to make copies of itself.
Upon exhausting the resources of the cell
it reaches a devasting point and is then forced
to kill itself.
As the cell bursts open releasing viruses, it also releases cytokines and inflammatory
markers causing and antigen-presenting
cells such as dendritic cells to approach
and bind to antigens of the virus.
The dendritic cell shares the antigen information
with the T lymphoctyes causing them to create
more inflammatory cytokines.
This where it gets tricky, cause in some people
the T lymphocytes especially produce a lot
more pro-inflammatory cytokines than needed, such pro-inflammatory cytokines include INTERLEUKINS
alpha and Tumor Necrosis Factor-Alpha
This causes a lot more white blood
cells to move into the lungs, and this is referred
to as a cytokine storm and could have terrible
effect which is destroying the lining of the
alveoli.
The destruction is mainly caused by neutrophiles
that release enzyme that degrades the membranes
of cells killing both infected and uninfected
body cells and the Killer T cells that command
both uninfected and infected cell to die through
apoptosis.
In most cases, the immune system regain control, 
but if this goes on for too long it would
scar the tissues of the alveoli and could
lead to lifelong disabilities.
The cytokines are also said to move from the
lungs to the rest of the body, and this process
of this disaster could repeat itself elsewhere
possibly leading to multiple organ failure.
That why around the beginning stages of infection
there may be lymphocytopenia meaning less
white blood cell present in the blood.
After some days the B lymphocytes create antibodies
specific to the virus’s antigen, the antibodies
created are said to be Anti-IgG and Anti-IgM.
These antibodies connect to the receptors
of the virus slowing reproduction and tagging
those viruses for destruction, this would mean that the would either be ingested
by macrophages or killed by neutrophils.
Also, the host cell sends out interferons which are cytokines that forces neighboring cells to produce
Anti-viral proteins to slow down or stop RNA protein synthesis.
Recovery begins.
Thank you and that was a summary on the Immunology behind COVID-19
