oat bio unit 21

The cows all started evolving and I don't know what this means for the beehive markets

1st line of defense

physical and chemical barriers

• Skin: physical; oily/acidic secretions from sweat glands

• Antimicrobial proteins: lysozyme in saliva and tears breaks down cell walls

• Cilia: lines the lungs and sweeps invaders out

• Gastric juice: I’M MMMEEEEELLLLLLTTTIIIIINNNNNGGGG

• Symbiotic bacteria: outcompetes other organisms inside internal organs

leukocytes

name for all white blood cells

innate immune cells

more general response, activated quicker, and response is always the same regardless of previous encounters.

adaptive immune cells

B, T, and NK cells, more specific to individual pathogens.

phagocytes

cells that engulf pathogens or cellular debris via endocytosis, and then break them down into small particles.

• Examples: neutrophils, monocytes, and dendritic cells.

neutrophils

most abundant WBC in the body, and destroys pathogens within infected tissues. They are drawn to infections via chemotaxis and enter tissues via diapedesis.

monocytes

circulate in the blood until they are needed to fight infections, where they move into cells via diapedesis and develop into macrophages.

macrophage

phagocytic cell that matures from monocytes and is used to phagocytize cell debris and pathogens.

antigen presenting cells

display fragments of pathogens on their own cells to activate T cells.

• Examples: macrophages, dendritic cells, and B cells.

2nd line of defense

Eosinophils, mast cells, basophils, and NK cells

eosinophils

work collectively to surround and destroy pathogens.

mast cells

used for allergic response, inflammatory response, and anaphylaxis.

basophils

involved in inflammatory response and recruited to tissues when needed.

nk cells

attack abnormal body cells like tumors or pathogen infected cells.

• Specifically infected cells with no MHC I receptors

• Part of both the innate and adaptive immune response.

toll like receptors

receptors on immune cells that recognize molecular patterns on the surface of pathogens.

cytokines

chemical signaling molecules used in the immune response for cell to cell communication.

interleukins

specific type of cytokine

• IL-1: inflammatory reaction

• IL-2: triggers adaptive immune response.

interferons

secreted by infected cells that stimulate neighboring cells to produce proteins to defend against a virus.

compliment system

innate response where proteins are circulating in the inactive state, then are activated to cause lysis of a pathogen.

inflammatory response

• Histamines secreted by mast cells cause vasodilation

• Prostaglandins act locally, causing inflammation, fever, and pain

• Increased blood flow + cytokines allows other immune cells to come to the rescue

diapedisis

When leukocytes enter tissues as a part of the inflammatory response by moving through gaps in blood vessel epithelium.

antigen

found on the surface of each pathogen and is unique to each pathogen.

antibody

aka immunoglobulins, which are Y shaped molecules produced by B cells and have glycoproteins that are specific to only one epitope.

epitope

a unique part of an antigen that is recognized by the immune system.

IgG

most abundant antibody and can cross the placenta

IgA

antibody found in breast milk and mucosa

IgM

1st antibody produced after exposure to antigen

IgE

antibody related to allergies

IgD

apparently the scientists don’t know what this antibody actually does

antibody structure

MHC

aka major histocompatibility complex

• Glycoproteins where the immune system can differentiate between self and nonself.

• Two types: MHC I on all nucleated vertebrate cells, and MHC II, only on antigen presenting cells.

MHC I with normal cell

• Regularly produced proteins and peptides in a cell are routinely broken down.

• These broken down fragments are loaded into MHC I to check if it is “self”

• No pathogens = no immune reaction.

MHC I with infected cell

• Regularly produced proteins and peptides in a cell are routinely broken down.

• These broken down fragments are loaded into MHC I to check if it is “self”

• ERROR!!!! THIS CELL IS INFECTED!!!! DEPLOY THE TROOPS NOW!!!!

MHC II in phagocytic cells

• Exogenous materials containing pathogens are ingested.

• These particles are presented on MHC II receptors.

• T cell receptors recognize the foreign particle and trigger a specific adaptive immune response.

MHC II in B cells

• B cell receptors bind to foreign antigen and bring it into the cell.

• These articles are presented on MHC II receptors.

• T cells interact with loaded antigen on B cell.

• T cell releases signaling molecules that trigger the B cell’s specific adaptive immune response.

2 branches of adaptive immunity

humoral response and cell mediated response.

humoral response

• Controlled by B cells

• B cells originate and mature in the bone marrow

• They bind directly to pathogens (no antigen presenting cell)

• B cell is activated and undergoes clonal selection

• Clonal selection produces memory B cells and plasma cells

• Upon a secondary infection, B cells rapidly proliferate

antibody functions

• Opsonization: tag pathogens for elimination by phagocytosis.

• Neutralization: Block the pathogen from interacting or being infective.

• Agglutination: causes pathogens to clump together.

• Enhancing other systems, like the compliment system.

cell mediated response

• Controlled by T cells

• T cells originate in bone marrow and mature in the thymus

• T cell receptors bind antigen fragments presented on MHC

• When a foreign antigen is encountered, T cells undergo clonal selection to produce four types.

4 types of T cells

• Helper T cells

• Cytotoxic/killer T cells

• Memory T cells

• Suppressor T cells

cytotoxic/killer T cells

Recognize antigens on MHC I and destroy by releasing perforins that trigger apoptosis.

Helper T cells

• Stimulate activation of B cells, cytotoxic T cells, and recruit other immune cells.

• Recognize antigens presented in MHC II.

Suppressor T cells

Play a negative feedback role in the immune system and prevent autoimmune responses.

T cell positive/negative selection

• T cell travels to thymus to mature

• Undergo positive selection in the thymic cortex if they can interact with MHC.

• Undergo negative selection in the medulla to check if they can bind to self antigens presented on the MHC.

• T cells that pass both types of selection are released from the thymus as mature T cells.

immune tolerance

• The ability to prevent an immune response against an antigen, like self antigens.

• Dysfunction of this ability can cause autoimmune disorders.

innate vs adaptive immunity overview

	Innate	Adaptive
Target	Nonspecific	Specific to pathogen
Speed	Fast/immediate	Slow
Duration	Short (hours/days)	Long (months/years)
Memory	No memory	Memory
Cells	Neutrophil, eosinophil, basophil, dendritic cell, macrophage, NK cells	B cells, T cells, antibodies, NK cells

acquired immunity

• Active: Developed after direct pathogen exposure.

  • Natural: Antibodies made after pathogen exposure

  • Artificial: Antibodies made after receiving vaccine

• Passive: Acquired from external sources.

  • Natural: Antibodies transferred from mom to baby

  • Artificial: Antibodies given via serum injection

vaccines

Use either dead or fragmented versions of pathogens to train the immune system to recognize the pathogen.

antibiotics

Chemicals derived from bacteria/fungi that are harmful to other microorganisms.

• Overuse can cause selection for antibiotic resistant bacteria and killing of helpful bacteria.

immune cell abundance

• Neutrophils > lymphocytes > Monocytes > Eosinophils > Basophils

• Never Let Monkeys Eat Bananananas.

• Natepipes Licked My Entire Butt

sprite can soda man