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The immune response is how an organism responds after being infected with a pathogen. A pathogen can be bacteria, viruses, or toxins. The immune response consists of both innate and adaptive immune responses.
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Jetzt kostenlos anmeldenThe immune response is how an organism responds after being infected with a pathogen. A pathogen can be bacteria, viruses, or toxins. The immune response consists of both innate and adaptive immune responses.
On pathogens, proteins live on the surface, known as antigens. There are specific antigens for each type of pathogen. Lymphocytes, a variety of white blood cells, can differentiate between whether or not a cell is an antigen or a cell from the body. Once they can differentiate, they produce antibodies to help destroy the antigens.
The innate immune response, aka non-specific immune response, defends the body against non-specific pathogens and is considered the first line of defence. Parts of the body such as skin and mucus form the innate immune response by keeping out pathogens. The mucus in our nose traps the pathogens from getting inside our bodies, and they also use their form of bacteria to destroy the stuck pathogens. In addition, various other cells are involved in the innate immune response as they carry out 'cell eating' – phagocytosis. These additional cells include neutrophils, macrophages, and monocytes.
The cells in the innate immune response are white blood cells that include neutrophils, macrophages, and monocytes.
Despite their many differences, they are all able to perform phagocytosis
While the innate immune system remains the same from birth, the adaptive immune system can learn over time. The adaptive immune response works to fight off pathogens and is especially effective against those it has destroyed before. Each time it encounters a pathogen, it will remember it in its memory, and it will be faster to defeat each time it sees it.
An example of an adaptive immune response is chickenpox. If someone gets sick with chickenpox regardless of age, they will never contract it again after fighting it off the first time.
There are only two types of cells in the adaptive immune response, T and B cells. T and B cells come from stem cells located in the bone marrow, and they are both classified as lymphocytes, which means they are the primary type of cell found in the lymph.
Although it is effective, it is slower to respond than the innate immune response due to it needing to identify the antigen before responding. This immune response splits into two types – humoral and cellular immunity. The adaptive immune response also requires fewer cells than the innate immune response.
Humoral immunity, or antibody-mediated immunity, is mediated by B cells. B cells move through the lymphatic system, where they encounter an antigen. Suppose the antigen matches the specific antibody on their cell surface, a membrane-bound antibody. In that case, they either split into a memory B cell, or an effector B cell occurs when plasma cells produce antibodies and allow them to move throughout the body.
Humoral immunity splits into both primary and secondary immune responses.
Primary immune responses occur when the body encounters a pathogen for the first time. These immune responses use the naive B and T cells. As the B and T cells have not transformed into their effector and memory cells, they are slow to respond to the threat to the point where it takes several days to react.
In contrast, the secondary immune response uses the memory forms of the B and T cells. Therefore, they respond in about half the time the primary response takes. They also produce higher levels of antibodies compared to the primary immune response.
This quicker response is why someone can never be infected with chickenpox again for the rest of their life.
Have you noticed that your armpits are sometimes swollen when you are ill? This is because your armpits are rich in lymph nodes, which contain lymphocytes. Swelling of the lymph nodes indicates high lymphocyte activity.
Cellular immunity involves the activation of lymphocytes upon encountering a 'non-self' material and is mediated by T cells. T cells are created in the bone marrow but travel to the thymus, a small organ located in the chest to get transformed into T cells. In the thymus, they develop T cell receptors where they will get a T cell receptor named CD4 or CD8. The different receptors allow the cells to perform different tasks.
Therefore, there are three types of T cells. Their jobs depend on what T cell receptor they receive. The Helper T cells have CD4 and help B cells and other cells found in the immune response. Cytotoxic T cells have CD8 and destroy pathogens plus infected self cells.
T regulatory cells have both CD4 and CD25, and its job is to identify what cells belong to the body, so they will not be attacked.
The receptors also need to perform recombination of genes that express these receptors. It is called rearrangement, and it allows for a large amount of diversity in the genes. Still, occasionally a mistake happens, and the gene is rearranged into an identical gene found in a person. This mistake leads to the body attacking itself. To prevent this response, T cells are tested twice by the body. The first test is to make sure they can tell the difference between their body's proteins and the proteins of a pathogen. The second test is to see how it will bind. If it attaches to something that is not an antigen or itself, it will be eliminated.
Vaccines help the immune response by pretending to be a pathogen. This makes the immune system believe that it is sick and needs to produce antibodies. Now that the immune system remembers how to fight off this pathogen, it can fight it off faster if the body ever actually becomes infected. The figure below shows a quick diagram of how it works.
The immune response is how an organism responds after being infected with a pathogen aka a form of bacteria, virus, or toxin.
Pathogens have proteins on their surface called antigens.
Antibodies are produced by the body and used to destroy pathogens.
There are innate and adaptive immune responses. Innate responses are nonspecific and what an organism was born with. Adaptive responses can grow as the organism comes in contact with pathogens and has two types of immunity, humoral and cellular.
Humoral immunity consists of B cells that either produce antibodies or remember previous pathogen attacks. Cellular immunity is when cells not belonging to the body are identified and are then destroyed by T cells.
During an immune response, cells in the innate immune system notice a pathogen. Cytokines are then released, the complement system is activated, and then the innate immune system calls for inflammatory responses.
The types of immune systems are innate, adaptive, primary, and secondary immune responses.
Producing antibodies and remembering prior pathogens
The immunity is through cells and not antibodies. Also, the cells are able to cooperate to help take down the pathogens.
Flashcards in Immune Response93
Start learningWhat type of molecule is an antibody?
An antibody is a protein, specifically an immunoglobulin or globular glycoprotein.
How are antibodies produced?
Antibodies are synthesized by B cells and plasma cells in the humoral immune response. They are synthesized in response to the presence of non-self material in the body, such as a pathogen or pollen.
What is the structure of an antibody?
An antibody is made up of four chains, two shorter light chains ad two longer heavy chains. These chains are connected by disulfide bridges. The variable region of the antibody is found at the top of the Y shape, and the constant region is found at the button of the Y shape.
Where is the antigen-binding site on an antibody?
The antigen-binding site is found at the two ends of the antibody’s Y shape, at the end of the variable region. The antigen-binding site is located at the ends of both the light and the heavy chains.
Why are the variable and constant regions named as they are?
The constant region is called constant because it is the same on every antibody, while the variable region is called variable because it has a specific shape that changes depending on the cell that has produced it.
What is agglutination?
Agglutination is when antibodies bind to multiple antigens, causing non-self cells or particles to clump together in one place. This makes it easier for phagocytes to engulf and destroy foreign material as they are all in one centralized place.
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