how are immune cells able to detect foreign pathogens? This is a topic that many people are looking for. newyorkcityvoices.org is a channel providing useful information about learning, life, digital marketing and online courses …. it will help you have an overview and solid multi-faceted knowledge . Today, newyorkcityvoices.org would like to introduce to you IMMUNE RESPONSE TO BACTERIAL INFECTION (Innate vs. Adaptive). Following along are instructions in the video below:
Beauty just pricked her finger. She may have fallen asleep. But her immune system is is hard at work an important part of her innate immune system her skin has breached and bacteria are entering her body the first immune cells.
They encounter are mast cells and dendritic cells these cells can distinguish self from non self. Thanks to the recognition of pathogen associated. Molecular patterns.
Or pa. Mps. Which are molecules associated with pathogens.
This. Recognition is not specific to any invader. But rather identifies a general attribute common to pathogens this.
Recognition is thanks to their pattern. Recognition. Receptors or prrs.
The pa. Mps. They recognize can include bacterial lipopolysaccharides.
Now that microbial components have been recognized the body springs into action and the inflammatory response. Is initiated. The mast cells stay on the battlefield.
Releasing histamine and heparin histamine causes vasodilation of nearby blood vessels and heparin as an anticoagulant. The result is increased blood flow to the infected area. Which allows more white blood cells to get there the mast cells also release cytokines which are cells signaling proteins that affect the behavior of nearby cells in this case.
The cytokines are used to call macrophages and neutrophils to the area macrophages are the largest phagocytic cells in the body and can engulf 100 pathogens each neutrophils are the most abundant white blood cells. They release cytokines as well amplifying. The inflammatory response they attack pathogens in three ways.
Phagocytosis engulfing. Pathogens. And they can ingest up to 20 each degranulation.
The release of soluble antimicrobials. And the release of neutrophil extracellular traps or nets nets are pretty cool. Think of neutrophils as the spider mans of your immune system with nets as their webs nets are primarily composed of the neutrophils dna and bind pathogens.
This binding occurs. Thanks to positively charged proteins on the bacterial surface interacting with negatively charged chromatin fibers. Meanwhile dendritic cells engulf antigens foreign substances that elicit an immune response and break them up into smaller pieces called epitopes dendritic cells are a type of antigen presenting cell or apc.
Because they then display the epitopes on major histocompatibility complex. 2. Or mhc at their surface dendritic cells move out of the infected area and into the lymph nodes.
So thus far all the defenses. Weve discussed belong to the innate immune system the innate immune system has nonspecific means of intruder identification and resistance. However when the dendritic cells enter the lymph nodes.
They link the innate immune system to the adaptive immune system. The adaptive immune system consists of t cells and b cells and brings in anti pathogenic weaponry. Specific to the attacker t cells are produced in the thymus differentiating into four types helper t cells cytotoxic t cells regulatory t cells or tregs and memory t cells helper t cells help with b and t cell differentiation and call macrophages and other cells to the battle cytotoxic t cells are the main soldiers binding and lysing infected cells they recognize infected cells thanks to antigens displayed on mhc class 1 molecules all nucleated cells have mhc class 1 molecules that can display antigens upon infection while only antigen presenting cells also have mhc class 2 molecules craigs use a negative feedback loop to regulate the immune response making sure it doesnt get too extreme and hurt.
The body unnecessarily importantly. They maintain tolerance to self antigens. Preventing autoimmune diseases memory t cells remain after the infection has passed in case of reinfection at which point they can rapidly multiply.
An amount of faster and stronger immune. Response. Helper t.
Cells and triggs are cd4 positive meaning that they express cd4 glycoprotein on their cell. Membranes cytotoxic t cells are cd8 positive and memory t cells can be either t cells are specific to one antigen after leaving the thymus they circulate the body until an apc presents an antigen that matches their t cell receptor or tcr following this initial activation the t cells cd4 or cd8 molecule also binds the mhc of the apc stabilizing the connection helper t cells and cytotoxic t cells also need secondary signals as well as cytokines to become fully activated following these signals the t cell begins to divide rapidly and moves to the site of inflammation to fight the pathogen at the infection site mast cells neutrophils and epithelial cells can produce cytokines to induce further activation and proliferation of the t cells immature b cells can be activated either by attaching to a free floating antigen or thanks to helper t cells or dendritic cells that present an epitope matching their b cell receptors or b c ours vcrs consist of a membrane bound antibody. Which is a large y shaped protein that binds antigens cd 79a and cd79b the b cell receptor and antigen undergo cell mediated endocytosis recognition of an antigen stimulates b cells to proliferate and the activated b cells undergo clonal expansion as they proliferate these many clones undergo somatic hypermutation basically an enzyme called activation induced deaminase or a.
I d introduces point mutations into the clones for some clones. This results in an increased affinity to the antigen while for others. This means.
A decreased affinity. The antigen is proteolytically broken down and an epitope is then displayed on the b cells surface attached to an mhc class 2 protein. Before the b cell can do anything a helper t cell with a complimentary tcr and cd4 positive glycoprotein must bind the antigen.
The t. Helper cell. Then releases cytokines that let the b cell.
Take the next step. This is a safety mechanism to prevent accidental activation of the b cells the b cells. That have decreased affinity.
Then undergo apoptosis while the b cells with increased affinity differentiate becoming either a plasma cell or a memory b cell. The plasma cells. Produce antibodies matching their vcrs into the blood and lymph meanwhile.
The memory b cells store antibodies in case of future reinfection when antibodies bind antigens they label them for destruction by cells. Such as macrophages. And neutrophils b cells.
Mediate your humoral immune response. So called because it involves substances in your body. Fluids.
So at the end of the day sleeping beauty wasnt just saved by prince phillip. But through the collaborative efforts of a whole army of immune cells insider. The primary immune response beat the infection.
A primary immune response is the immune systems response to the first exposure to a particular pathogen. There is a latent period during which the adaptive immune system is mobilized since appropriate t and b cells need to be found in cloned. However memory t and b cells.
Ensure that a secondary immune response should the same pathogen every infect will be much stronger. And faster. If you liked this video please like and subscribe.
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