immune system 2 Flashcards
Macrophages (phagocytes)
Macrophages are phagocytic white blood cells. The role of macrophages is to engulf and digest pathogens in order to maintain homeostasis. This is done by first detecting the pathogens through the chemicals it releases. Then, it ingests the pathogen by wrapping itself around it. Then, it fuses with a lysosome to digest and break down the pathogen. Then, the broken down material is discharged.
B lymphocytes/B cells (plasma & memory B cells)
A B lymphocyte (B cells) secretes antibodies with the help of plasma B cells. The antibodies are attached to the B cell’s surface and have unique binding sites. When the B cell encounters an antigen, the B cells divide through mitosis to create multiple copies of itself. These copies become memory B cells so your immune system can recognize the antibodies in the future.
Antigen versus antibody
An antigen is any molecule that enters the body and triggers an immune response. Antibodies replicate, attack, and destroy antigens if they enter the body again.
How does HIV infect the body on a cellular level?
HIV infects T helper cells which causes the inability to activate B cells and for them to produce antibodies, leading to the development of AIDS. HIV infects a cell by making a DNA copy from its RNA, with the help of transcriptase. The cDNA that is produced is then inserted into the host’s cell genome. HIV is spread through direct contact whether it be skin-to-skin or fluid-to-fluid.
T lymphocytes/T cells
T lymphocytes (or T cells) help B cells make antibodies. The APC (Antigen Presenting Cell) traps the antigen and presents it to the T helper cell. Once the antigen has been recognized by the T helper cell, it triggers the production of antibodies and activates macrophages to engulf and destroy the antigen.
Florey & Chain
After the discovery of penicillin by Fleming, Florey & Chain infected 8 mice with pneumonia. Then, 4 out of 8 of the mice were injected with penicillin. The mice that were not treated died within 24 hours, while the mice that were treated survived. Florey & Chain then tested penicillin on human patients with infections and most patients survived.
Resistance to antibiotics
When a mutation occurs that causes resistance to an antibiotic, after several generations, the strain of bacteria will evolve genes that are resistant to the antibiotic. In some cases, bacteria can exchange genes coding for antibiotic resistance and develop resistance to multiple antibiotics. An example of multidrug resistant bacteria is staphylococcus aureus.
Antibiotic
An antibiotic is a medicine that inhibits the growth of or destroys bacteria by destroying its cell wall. Antibiotics are ineffective against viruses because they do not have a cell wall for it to attack.
Non-specific/innate immunity
Non-specific/innate immunity is the first line of defense. It does not distinguish one pathogen from another. Its response is rapid because it’s present before any exposure to pathogens. The response is short and it does not result in any immune memory. Some examples are macrophages and the skin.
Specific/adaptive immunity
The specific response is the second line of defense. It responds to a specific pathogen type. Its response is slower because it requires specialized cells/structures to be activated. The duration of the response is longer and builds immune memory. Some examples are B cells and T cells.
