UNIT 9 -IMMUNITY

MHC-1

(MAJOR HISTOCOMPATIBILITY COMPLEX) - healthy cells produce this. Polymorphism in MHC genes =chances of matching antigens. - MHC diversity = disease resistance. - each MHC gene has ~100 alternative alleles.

Innate immunity

(non specific immunity) - responds RAPIDLY to all kinds of pathogens in the same way

Plasma cells

(or effector cells) Effector cells are the relatively short-lived activated cells that defend the body in an immune response. Effector B-cells are called plasma cells and secrete antibodies, and activated T cells include cytotoxic T cells and helper T cells, which carry out cell-mediated responses. - tag and neutralize pathogens.

Mast cells

(part of the second line of defense) A mast cell (also known as a mastocyte or a labrocyte) is a type of white blood cell. Mast Cells rupture to release histamine.

Macrophages

(type of phagocyte) "big eaters" don't travel but hang in various organs. can eat up

Neutrophils

(type of phagocyte) moves quickly through the blood stream to kill invading microbes before dying - dead neutrophils collect and form pus.

Phagocytes

A kind of leukocyte that is specific to the INNATE IMMUNE SYSTEM. Ingest microorganisms through the process of PHAGOCYTOSIS

• How and why do we have an allergic response?

Allergies: inflammation gone awry! antihistamines required to quell the response

Antigen presentation (by HLA = MHC molecules)

An antigen-presenting cell (APC) or accessory cell is a cell that displays antigen complexed with major histocompatibility complexes (MHCs) on their surfaces; this process is known as antigen presentation. T cells may recognize these complexes using their T cell receptors (TCRs). The human leukocyte antigen (HLA) system, the major histocompatibility complex (MHC) in humans, is controlled by genes located on chromosome 6. It encodes cell surface molecules specialized to present antigenic peptides to the T-cell receptor (TCR) on T cells.

• Describe the function of B-cells.

B cells, also known as B lymphocytes, are a type of white blood cell of the lymphocyte subtype. They function in the humoral immunity component of the adaptive immune system by secreting antibodies

B-cells

B-cells function in the humoral immunity component of the adaptive immune system by secreting antibodies. produced in bone marrow (& spleen) -bacteria (extracellular pathogens), etc

Dendritic cells

Dendritic cells (DCs) are antigen-presenting cells (also known as accessory cells) of the mammalian immune system. Their main function is to process antigen material and present it on the cell surface to the T cells of the immune system. They act as messengers between the innate and the adaptive immune systems. Epithelial tissue has Dendritic Cells - present their antigens to immune system. - phagocytize pathogens type of phagocyte on the surface of much of the body - eat up pathogens and then carry info about them to spleen or lymph nodes.

Memory cells

Helper T & Cytotoxic T Cells both form Memory T-Cells. they keep record of the intruders an

Helper T-cells

Helper T cells, influences or controls the differentiation or activity of other cells of the immune system. Direct phagogytes based on info they get from IMMUNE CELLS.

Humoral response

Humoral immunity is the aspect of immunity that is mediated by macromolecules found in extracellular fluids such as secreted antibodies, complement proteins, and certain antimicrobial peptides. Humoral immunity is so named because it involves substances found in the humors, or body fluids.

• What does a dying cell do in the final moments of its life? Explain in detail.

Infected cells make MHC* molecules to bind to synthesized virus proteins. MHC molecules then move antigens to cell's surface. T cells bind to presented antigens that they match ... ... and destroy infected cell

Memory T-cells

Memory T cells - keep records of intruders and provide future immunity against it

What type of cell specifically kills other human cells

Natural Killer Cells

Natural killer cells

Natural killer cells attack our own human cells that are infected or cancerous.Natural killer cells or NK cells are a type of cytotoxic lymphocyte critical to the innate immune system - infected cells don't make MHC-1s, the body's ID card. - they phagocytize them

Antihistamines

Prevent unnecessary inflammatory responses An antihistamine is a type of pharmaceutical drug that opposes the activity of histamine receptors in the body

Acquired (adaptive) immunity

The adaptive immune system must learn about every pathogen it interacts with and store this information

• Describe your 2° line of defense.

The inflammatory response (inflammation) 2nd Line of Defense: Inflammation Ruptured Mast cells release histamines that: - dilate capillaries to⬆ blood flow & make them leaky. - attract phagocytes: leucocytes, macrophages & mast cells Natural killer cells attack our own cells - infected cells don't make MHC-1s, the body's ID card. - they phagocytize them Allergies: inflammation gone awry ! antihistamines

Inflammation response

The inflammatory response (inflammation) occurs when tissues are injured by bacteria, trauma, toxins, heat, or any other cause. The damaged cells release chemicals including histamine, which cause blood vessels to leak fluid into the tissues, causing swelling

• Describe the inflammation response.

The inflammatory response (inflammation) occurs when tissues are injured by bacteria, trauma, toxins, heat, or any other cause. The damaged cells release chemicals including histamine, which cause blood vessels to leak fluid into the tissues, causing swelling

• What animals have innate immunity & what have acquired immunity?

The innate immune system is an evolutionarily older defense strategy, and is the dominant immune system found in plants, fungi, insects, and primitive multicellular organisms For a long time it was believed that adaptive immunity was confined to vertebrates (with a few exceptions like lampreys which appeared to lack it). In fact, very many invertebrates have adaptive immunity. They use different systems from that familiar from vertebrates and often different systems from each other. Insects are included.

Cell-mediated response

The role of effector T cells in cell-mediated and humoral immune responses to representative pathogens. Cell-mediated immune responses involve the destruction of infected cells by cytotoxic T cells, or the destruction of intracellular pathogens by macrophages

Cytotoxic T-cell

Type of T-cell lymphocyte that is responsible for destroying infected cells before they release mature parasites.

• Describe how antibodies act.

When an antigen enters the body, the immune system produces antibodies against it. Antibodies are always Y-shaped. It is like a battle with the army (antibody) fighting off the invader (antigen).

Leucocytes

White blood cells (WBCs), also called leukocytes or leucocytes, are the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders. They can go anywhere other than the central nervous system (brain and spinal cord). They move through blood stream and send signals to the capillaries to open up, allowing them to access to wherever they are needed.

WBCs

White blood cells (WBCs),carry out much of the Immune Response.

Pathogens

a bacterium, virus, or other microorganism that can cause disease

T-cells

a lymphocyte of a type produced or processed by the thymus gland and actively participating in the immune response. Thymus - a lymphoid organ situated in the neck of vertebrates that produces T cells for the immune system. diverse antigen receptors -two specialized forms: Cytotoxic T cell !Helper T cell

• Why is it important that macrophages "present" antigens from pathogens they killed?

a macrophage will present the antigen (a molecule, most often a protein found on the surface of the pathogen and used by the immune system for identification) of the pathogen to the corresponding helper T cell. The presentation is done by integrating it into the cell membrane and displaying it attached to an MHC class II molecule (MHCII), indicating to other white blood cells that the macrophage is not a pathogen, despite having antigens on its surface.

Allergens

a substance that causes an allergic reaction.

Antigens

a toxin or other foreign substance that induces an immune response in the body, especially the production of antibodies.

Antibodies

highly specialized surface proteins produced by B-cells that match those antigens. They cant destroy but can only 'tag' the invading microbe. Antibody binding: - tags that pathogen for destruction, and ... - stimulates that B-cell to secrete more antibodies. !Thus, antigens are antibody generators

Histamines

makes blood vessels more permeable - allows fluid to flow to affected area causing inflammation and bringing in WBC.

Describe your 1° line of defense.

skin and mucous membranes (viscous fluid that traps microbes) - in digestive tract as well (technically outside the body) and secretions

Lymphocytes

undergo reproduction and diferenciation i..e 'CLONAL SELECTION' to