Stig A. is a highly accomplished scientist and doctor of sciences who has made significant contributions to the fields of medicine and biology. He is best known for his work on the human immune system, which he has studied extensively over the course of his career. In addition to his work in the medical field, Stig A. has also made significant contributions to the fields of ecology and environmental science. He is currently a professor at the University of Copenhagen, where he continues to conduct research and teach students about his findings.
The human immune system is responsible for protecting the body from infection and disease. It does this by recognizing foreign invaders, such as viruses or bacteria, and attacking them before they can cause harm. The immune system is made up of a network of cells, tissues, and organs that work together to protect the body. The first line of defense against foreign invaders is skin and mucous membranes, which form a barrier that prevents most microbes from entering the body. If these barrier defenses are breached, special cells called antigen-presenting cells (APCs) will alert the rest of the immune system to the presence of an invader.
Once alerted to an invader’s presence, various types of white blood cells will begin working to destroy it. These include: natural killer cells (which kill viruses and cancer cells), macrophages (which eat bacteria), neutrophils (which eat fungi), T-cells (which help coordinate immunity), B-cells (which produce antibodies). Antibodies are proteins that attach themselves to foreign invaders and mark them for destruction by other components of the immune system. The final stage of immunity is when killer T-cells directly attack infected host cells in order to prevent them from replicating or producing more virulent toxins .
Vaccines work by mimicking an infection without actually causing sickness. When a person is vaccinated, they are injected with a “dead” or “modified” version of a virus or bacterium . As that person’s immune system responds to destroy the vaccine , they also develop immunity against future infections with live versions of those same viruses or bacteria . Immunization via vaccination is one of public health’s great success stories; vaccines have eradicated smallpox globally and continue to prevent millionsof deaths each year from diseases like measles , polio , tetanus , diphtheria , pertussis (whooping cough) .