Unit 5 Terms - Influenza

Cell-mediated Immunity

Cell-mediated immunity targets cells of our bodies that have become infected with pathogens and are presenting the antigen. makes use of the helper T cells.

Disruptive Selection

Changes in the environment cause the average, or most common, form of variation to be detrimental and favors the variants at the ends of the distribution.

Directional Selection

Changes in the environment direct natural selection to favor the variants at one end of the distribution. This causes a shift in the distribution of the trait over time toward one of the extremes.

Clotting Factors

Clotting factors close off the wound. This causes pressure to build and accounts for the red, tender appearance of inflammation.

Natural Selection

Darwin proposed that natural selection allows populations to adapt to a new environment, and is the basis of the process of evolution. *Individuals vary in their traits* Variation exists in a population for heritable traits. This does not just include physical characteristics, such as beak shape, but also physiology and behavior. *Individuals struggle to exist.* Populations produce more offspring than can survive, which creates competition for available resources. *Individuals differ in their fitness.* Individuals who have favorable traits will survive at a greater rate than those without them. When these individuals reproduce, they pass these traits on to the next generation. The term fitness is often used to describe this reproductive success. *Populations become adapted to the environment.* Over time, natural selection increases the frequency of the advantageous trait in the population and decreases the frequency of detrimental traits. Over multiple generations, the population becomes adapted to the new environment.

Natural killer Cells

Destroy cells of the body that have been infected by viruses or bacteria​ Nonspecific​

Macrophage

Destroy pathogens by phagocytosis Large white blood cell that removes bacteria, foreign particles, and dead cells When pathogens are ingested by the macrophages and dendritic cells of the immune system, they are digested, and a small portion of the pathogen is attached to the surface of the macrophage.

Thomas Malthus

Economist who stated that populations (in this case, humans) sometimes increase at rates faster than their food supply can increase, thus creating competition. ​

Aluminum Salts

Enhances the ability of the immune system to detect the virus. Some vaccinations are aluminum-free.​

Epithelial Cells

Epithelial cells form the boundary between the tissues of our bodies and internal environments, such as the respiratory tract and digestive tract.​

Evolution

Evolution is the result of changes over multiple generations. In some cases, these changes may take millions of years to produce a detectable change, and in other cases, it may occur relatively rapidly. Human influenza viruses originate in animal hosts, such as the pig and bird. ​ As the viruses exchange genetic material, they evolve into new forms that can then be transmitted to humans, causing flu outbreaks.​

Release

Finally, the new viruses are ready to leave the cell. This is possible by either causing the host cell to burst (called lysis) or by exiting through the plasma membrane (exocytosis). the exit is sometimes aided by an enzyme provided by the virus. Viruses that possess an outer envelope leave by endocytosis. As they exit, they often create an envelope about themselves by acquiring pieces of the host cell's plasma membrane.

Charles Lyell

Geologist who proposed that the Earth's surface is dynamic and constantly undergoing erosion and uplift, which explained how the different fossil layers were formed.

Interleukin

Glycoprotein that is involved in regulating the general immune response.

Glycoproteins

Glycoproteins located along the plasma membrane of the cell act as identification tags. used in recognizing self and non self. (a protein with a sugar attached)

H Spike

H spikes are associated with hemagglutinin, a type of glycoprotein that assists the virus in identifying the receptors on the host cell.

HIV

HIV is an example of a virus in humans that used the lysogenic cycle. Scientists have estimated that almost 8% of the human genome is actually viral in nature, and thus evidence of how active the lysogenic cycle has been in our evolutionary history. HIV is an RNA virus

Formaldehyde

Inactivates any toxins from the viruses or bacteria that may have been present during production.​

Histamine

Increases the permeability of the capillaries and causes fluid to be released into the area of a wound.

Influenza B

Influenza B viruses have a lineage designation (either B/Yamagata or B/Victoria) that help identify the history of the virus.

MHC-I

MHC class I markers (MHC-I) are present on every nucleated cell of the body. This is the general "self" identification tag. ​ used by the immune system to distinguish self and non self.

MHC-II

MHC class II markers (MHC-II) are only present on the immune system cells that provide the link between the nonspecific and specific immune responses

Respiratory Tract

Mucous membranes trap microbes; they contain chemicals that protect against pathogens; cilia this is what influenza targets, specifically our epithelial cells.

N Spike

N spikes help break down the mucous material surrounding host cells in the respiratory tract and initiate penetration of the virus into the host cell.​

Erasmus Darwin

Naturalist and philosopher who proposed that evidence from animal development and animal breeding suggested that species may evolve over time.

Charles Darwin

Naturalist and philosopher who proposed that evidence from animal development and animal breeding suggested that species may evolve over time. Darwin's observations of the finches and tortoises of the Galápagos provided him with his ideas on how natural selection drives evolutionary change.

Jean-Baptiste Lamarck

Naturalist who believed that complex life forms are descended from simpler forms. Proposed that individuals can acquire characteristics that enable them to evolve over time. This idea is referred to as inheritance of acquired characteristics.

Neutrophils

Neutrophils remove dead cells, wound debris, and any pathogens in the area by phagocytosis. If additional assistance is needed, neutrophils may release cytokines to recruit more immune cells to the area.

Core Proteins

Newer vaccines are being designed to use other proteins within the capsid of the virus as the basis for programming the adaptive responses. These proteins, sometimes called core proteins, do not change at the same rate as the H and N spikes on the virus, and are more similar between influenza viruses.

Spikes

On the surface of an influenza A virus are two different types of spikes. These spikes are a type of glycoproteins (a protein with a sugar attached) that assist the virus in identifying and entering its host cell.​ H and N spikes

Uncoating

Once inside the cell, some viruses provide an enzyme to remove their genetic material from the capsid.

2. Penetration

Once the virus has identified the host, its genetic material enters the cell. This can occur by injecting the genetic material directly into the host cell (leaving the capsid outside), or by convincing the host cell to engulf the entire virus (a process called endocytosis). In the case of influenza, the latter process occurs and once in the cell the virus releases its genetic material into the host cell.

Spleen

Organ where blood is filtered and cleaned by the action of white blood macrophages.

Thimersol

Preservative that may be present in some multi-dose vials of the vaccine.​

Antibiotics

Prevents bacterial growth during preparation and storage of the vaccine.

Egg Protein

Remnants from the production of the vaccine. Newer vaccines that do not use eggs during production will not have these proteins present.

Stabilizing Selection

Selection favors the most common form of variant for the trait, and selects against the extreme variants. In this case, the average individual is most adapted to the environment.

Gelatin

Stabilize the vaccine and protect it from temperature variations during storage.​

Analogous

Structures that serve the same function, and often may appear the same, but that evolved independently as adaptations to a specific environment. Wings of birds, bats, and insects are examples of analogous structures. ​

T Lymphocytes

Target cells that have been infected by a specific pathogen​ Cell-mediated immunity makes use of T lymphocytes, which are white blood cells produced in the bone marrow. ​ After being formed, T lymphocytes travel to the thymus where they mature. As they mature, each T lymphocyte develops receptors that will allow it to recognize a single form of antigen.​

Reverse Transcriptase

The HIV virus is an example of an RNA virus. This presents a problem for the virus, because the host cell's protein synthesis processes require DNA as the starting template. ​ Therefore, before the proteins for new viruses can be manufactured during the biosynthesis stage, the virus must convert its RNA into DNA. This is done by an enzyme, supplied by the virus, called reverse transcriptase.​

Memory

The adaptive immune response also has the ability to remember past exposures to pathogens. This characteristic is called memory. Some of the activated B cells are held in reserve and not used in the first response to the antigen. Instead, they wait for a future exposure. Memory T cells are also produced by the cell-mediated immunity pathway.

Cytokines

The chemical signals of the immune response are collectively called cytokines. A cytokine is a small protein that is usually involved in a local response to a pathogen. Cytokines act as an alarm to the organ systems of the body, alerting them that a pathogen is present. ​this is what causes the symptoms of the flu.

Innate Defenses

The defenses that act as general defenses, meaning they are not targeting a specific pathogen, are collectively called the innate defenses.​

Envelope

The envelope is actually the remnants of the plasma membrane of the host cell. Rather, it assists in the attachment and entry of the virus into a host cell.

Fossil Record

The fossil record not only provides us with ideas of what organisms were like in the past, but gives us an indication of how they have evolved over time. Transitional fossils are of special interest to evolutionary biologists because they represent intermediate forms and are an excellent example of Darwin's idea of descent with modification.​

Non-Self

The immune system distinguishes "self" from "non-self" by a series of markers present on the plasma membrane of each cell. macrophages tagged as non self can trigger an immune system response

1. Attachment

The structure of the proteins in the capsid allows it to recognize and target specific cells for infection.

Genome

The sum of all of the genes in an organism (or species) is commonly called its genome

Lymph Nodes

Tissue where interstitial fluid is filtered and cleansed by white blood cells called macrophages.

Red Bone Marrow

Tissue where the lymphocyte cells of the body are produced. Location where B lymphocytes mature.

Integration***

To process and interpret sensory input and decide if action is needed

Vaccine

Vaccinations expose the immune system to an antigen specific to a pathogen, without causing the associated disease. Later exposure (the secondary response) is more rapid and effective due to the initial exposure.​

Genes

Within the DNA of an organism are sets of instructions, called genes. ​

Georges Cuvier

Zoologist who studied the fossil record and noticed that it showed a succession of different forms of life over time. However, he believed that all species were created at the same time, and that catastrophic events had caused some to go extinct.

Bacteriophage

a DNA virus with a polyhedral head and a helical tail.​

Reproduce

also referred to as "Fitness;" to produce more offspring

Self

an own organism's cells

Influenza A

if the virus is influenza A, this is followed by a nomenclature on the types of spikes found on the surface of the virus. Influenza virus is an RNA virus with a spherical capsid surrounded by an envelope with spikes.​

Antigenic Drift

occurs when there are small changes in the surface spikes of the influenza virus.

Lysogenic

or it can integrate directly into the host cell genome and delay its own reproduction until a later time. the virus remains inactive or latent As the host cell divides, the viral DNA is replicated along with the host cell DNA, thus creating new cells that contain the virus. The virus remains latent until some environmental factor signals it to reenter the lytic cycle and begin the process of biosynthesis and maturation.​ ex: HIV

Pandemic

scientists review data to determine each flu virus's potential to cause a worldwide pandemic, what is known about the strain of the virus, and the ability to produce an effective vaccine against the strain. ​

RNA

single-stranded nucleic acid that contains the sugar ribose. Some viruses contain RNA and must use reverse transcriptase to create DNA to input into a host cell.

Homologous Structure

structures that are similar because they have been inherited from a common ancestor. The bone structure of the limbs of a mouse, bat, and whale are all similar because these mammals all descended from a common ancestor.

Adaptive Immunity

targets specific antigens associated with a pathogen, and also has the ability to remember past responses.​ Adaptive immunity has the ability to target cells of the body that are infected with the pathogen, while also responding to any pathogens that are free in the blood or interstitial fluid of the body.​

Tiktaalik

transitional fossil between fish and tetrapods

Antigenic Shift

two different forms of the virus infect the same cell.​ mechanism the influenza virus has of evading the immune system When this happens, the host cell may manufacture viral particles from both viruses, and then reassemble them into a new form that contains unique versions of H and N spikes. An antigenic shift causes a more rapid change in the virus. Because our immune system has not been exposed to this form of the virus before, it takes longer to respond to it and thus an outbreak in a population may more easily result.

Lytic

viruses can either immediately begin using the resources of the host cell to manufacture new viruses

4. Maturation

Also known as assembly, this is when the pieces of the virus are assembled.

Stomach

Hydrochloric acid (low pH) destroys bacteria and other pathogens.​

Skin

Normal bacteria (flora) on the surface, along with chemicals released by oil and sweat glands, inhibit bacterial growth.​

Thymus

Organ where T lymphocytes mature.​

B Lymphocytes

Produce antibodies to target specific antigens in the fluids of the body​

Trivalent

The most common vaccine contains three viruses. This is called a trivalent vaccine

Dendritic Cells

When pathogens are ingested by the macrophages and dendritic cells of the immune system, they are digested, and a small portion of the pathogen is attached to the surface of the macrophage.​

Prophage

the viral DNA that is embedded in the host cell's DNA

Capsid

A protein coat that surrounds the genetic material. The capsid may have proteins attached to it, such as tail fibers or spikes, that assist the virus in attaching to the target host cell.​

Quadrivalent

A vaccine directed against four viral strains.

Interferon

Acts as a signal to nearby cells that a cell has been infected by a virus.

DNA

Adenovirus is a DNA virus with a polyhedral capsid and a fiber at each corner; Bacteriophage is a DNA virus with a polyhedral head and a helical tail.​

Antigen

An antigen is any substance that produces a specific immune response by the body. Antigens are usually proteins or large carbohydrates that are specific to pathogens such as bacteria and viruses.

Archaeopteryx

An intermediate fossil that shows both reptile and bird characteristics.

Giant Viruses

As their name suggests, these viruses are much larger than a typical virus (which may be as small as 10 micrometers in size), with some almost half the size of a bacteria.

Antibody-mediated immunity

At the same time that helper T cells and cytotoxic T cells are working to target infected cells, the B lymphocytes begin the production of antibodies. ​ This is the second form of adaptive immunity

3. Biosynthesis

At this point, the virus hijacks the host cell's machinery to manufacture new capsid proteins and copies of its genetic material. Energy and materials for these processes are all provided by the host cell.​