Skin, tears and mucus are part of the first line of defence in fighting infection. They help to protect us against invading pathogens. You have beneficial bacteria growing on your skin, in your bowel and other places in the body (such as the mouth and the gut) that stop other harmful bacteria from taking over.
Health expert: Your immune system is the best defense against any virus or infection.
The innate immune system is the body's first line of defense against germs entering the body. It responds in the same way to all germs and foreign substances, which is why it is sometimes referred to as the "nonspecific" immune system.
Skin is a barrier that serves as one of the body's first lines of defense against harmful microbes. Specialized immune cells within skin tissue help to fight invading organisms. Yet the skin hosts diverse communities of beneficial bacteria, collectively known as the skin microbiota.
The immune system's three lines of defense include physical and chemical barriers, non-specific innate responses, and specific adaptive responses.
The cells of the innate immune system provide an early response to danger. They move through the body looking for signs of damage or infection of other cells. Then they destroy those cells. Another major defense is called the adaptive immune system.
Not only do they have to breach physical and chemical barriers, they've got to dodge front-line cells and evade tools specially trained to seek and destroy them. The three lines of defense are barrier defenses,the innate immune system,and the adaptive immune system.
The second line of defense are the non-specific phagocytes and other internal mechanisms that comprise innate immunity.
If an antigen enters the body and B-cells recognize it (either from having had the disease before or from being vaccinated against it), B-cells will produce antibodies. When antibodies attach to an antigen (think a lock–key configuration), it signals other parts of the immune system to attack and destroy the invaders.
These specialized cells and parts of the immune system offer the body protection against disease. This protection is called immunity. Humans have three types of immunity — innate, adaptive, and passive: Innate immunity: Everyone is born with innate (or natural) immunity, a type of general protection.
Barriers to Pathogens. The body's first line of defense consists of three different types of barriers that keep most pathogens out of body tissues. The types of barriers are mechanical, chemical, and biological barriers.
Healthy immunity accomplishes four essential principles: (1) ability to detect and fight off infection; (2) ability to recognize a host's own cells as "self," thereby protecting them from attack; (3) a memory from previous foreign infections; and (4) ability to limit the response after the pathogen has been removed.
Two types of immunity exist — active and passive: Active immunity occurs when our own immune system is responsible for protecting us from a pathogen. Passive immunity occurs when we are protected from a pathogen by immunity gained from someone else.
Second line of defense
An inflammatory response begins when a pathogen stimulates an increase in blood flow to the infected area. Blood vessels in that area expand, and white blood cells leak from the vessels to invade the infected tissue. These white blood cells, called phagocytes engulf and destroy bacteria.
Natural killer cells (NK cells) are white blood cells that destroy infected cells and cancer cells in your body. NK cells are important fighters in your immune system. Your immune system protects you from harmful invaders, like pathogens (viruses, bacteria and parasites) and cancer cells.
Fever, although part of the second line of defense in immune response, is still a topic of discussion on whether an increase in body temperature during an infection is more beneficial than harmful.
It is now recognized that inflammation induced by microbial infection and tissue damage is an essential mechanism of innate immune response. Proper inflammatory responses provide broad spectrum protection against infections and orchestrate long-term adaptive immunity toward specific pathogens.
It is said that ostriches have the strongest immune system of any animal in the world.
Recent studies have shown that women have a better immune system against infections than men. This is due to the genetic structural difference. This genetic structure is known as microRNAs.
Calling in the “special forces”
Of these, dendritic cells are the most common and powerful APC type. They are considered to be the bridge between the innate and adaptive immune responses. Dendritic cells are produced in bone marrow and migrate through the blood to tissues where they monitor for pathogens.
Vaccines provide active immunity to disease. Vaccines do not make you sick, but they can trick your body into believing it has a disease, so it can fight the disease. Here is how a vaccination works: The vaccine is administered.
Type 1 immunity is critical for defence against many intracellular pathogens, bacteria, viruses and other microorganisms. By contrast, type 2 immunity promotes immunity against extracellular parasites and helminths, helps to maintain metabolic homeostasis and regulates tissue repair following injury.
For most infections, save those caused by large eukaryotic pathogens, type 1 immunity is protective, whereas type 2 responses assist with the resolution of cell-mediated inflammation.