VCE unit 4 Biology - Immunity 2022

ability to resist infection by action of antibodies or lymphocytes

immunity

MHC I proteins that enable immune system to determine which cells belong

self

molecules not found on self cells which begin immune reaction to eradicate it

non-self

immune response mechanisms that are innate within the body to counteract pathogens

non-specific immunity

bodily structures and mechanisms that prevent pathogens from entering and infecting the body

first line of defence

special cellular layer which prevents entry (e.g. intact skin, stomach and intestinal lining)

physical barrier

secretion of chemicals that limit pathogen growth in parts of the body

chemical barrier

good bacteria which compete for space and nutrients with possible pathogens to restrict their growth

natural flora

the regular removal of pathogens out of the body

flushing

nonspecific resistance against pathogens in a generalised form

second line of defence

monocyte which engulfs and absorbs pathogens

phagocyte

lymphocyte which destroys infected or cancerous cells through injection of cytotoxins into diseased cell

killer cell

ingestion of pathogen by phagocytes

phagocytosis

protein which binds to antigens to attract and stimulate phagocytosis

complement protein

protein which inhibits virus replication

interferon

physical condition where region of body becomes red, swollen, hot and painful

inflammation

blood which has been converted into a solid state by platelets and fibrin

blood clotting

immune response mechanisms that are acquired by the body to counteract pathogens

specific immunity

a leucocyte (white blood cell) which occurs in the lymphatic system that is largely responsible for immune responses

lymphoctye

lymphocyte processed in the bone marrow that is responsible for producing antibodies

B cell

immune response involving the transformation of B cells into plasma cells that produce and secrete antibodies to a specific antigen

humoral response

proteins which are present in antibodies that are secreted by plasma cells

immunoglobulin

unique molecule that can induce an immune response

antigen

protein produced by plasma cells to counteract a specific antigen to recognise the pathogen as non-self

antibody

long-lived lymphocyte capable of responding a particular antigen on its reintroduction long after the exposure that prompted its production

memory cell

lymphocyte that is produced in the thymus that is activated when the MCHII proteins recognise specific antigens

T cell

type of T cell which regulates and suppresses the immune response by releasing cytokines

helper T cell

type of T cell which releases cytotoxic granules to apoptosize cancerous and infected cells.

cytotoxic T cell

immune response which activates phagocytes and cytotoxic T cells and releases cytokines in response to an antigen

cell mediated response

colourless fluid containing lymphocytes, which bathes the tissues and drains through the lymphatic system into the bloodstream

lymph

structures which remove fluid leaked into tissues from the bloodstream to be returned to the circulatory system

lymph vessel

swellings in the lymphatic system that trap antigens and present them to the lymphocytes for immune response

lymph node

immune response which involves own immune system and creation of memory cells

active immunity

immune response and creation of memory cells are a result of exposure to a living pathogen

natural active immunity

immune response and creation of memory cells are a result of exposure to a non-living pathogen

induced active immunity

treatment with a deceased or inactive pathogen to produce immunity against a disease

vaccination

resistance to the spread of a contagious disease within a population which results in a high proportion of individuals being immune to the disease, especially through vaccination

herd immunity

protection from pathogens through the antibodies produced from another human or animal

passive immunity

protection from pathogens through the antibodies produced from another human or animal who were exposed to living pathogen

natural passive immunity

protection from pathogens through the antibodies produced from another human or animal who were exposed to a non-living pathogen

induced passive immunity

blood serum containing antibodies and is used to pass on passive immunity for many diseases

antiserum

harmless substance which causes an allergic reaction

allergen

immune response to an allergen

allergic response

condition where mother has Rh- blood and child has Rh+ blood which can cause immune response against fetus

rhesus incompatibility

disease in which immune system recognises self as a non-self antigen, thus attacking it

autoimmune disease

when immune response overreacts and is highly sensitive to an harmless substance

hypersensitivity

failure of the immune system to protect the body from infection, due to the absence of immune response cells and mechanisms

immune deficiency disease

antibody produced by single clone of cells and consisting of identical antibodies

monoclonal antibody

Inflammation

Increased blood flow to damaged areas, increased permeability of blood vessels allows white blood cells to be attracted to the site.

Fever

Increase in body temperature to cause pathogen growth to slow and improves the inflammatory response.

Cytokines

Signaling molecules that indicate the presence of damage or of an invader triggering various responses from the immune system.

Interferons

A cytokine that is produced by virus infected cells signaling to the immune system the presence of a virus.

Complement Proteins

An array of blood proteins which can kill cells recognize as non-self.

Phagocytes

Large groups of white blood cells that engulf and digest foreign cells.

Natural Killer T cells

Detect infected or diseases body cells and release chemicals that cause the cell to lyse.

Neutrophils

A type of phagocyte that rapidly enter the cell and engulf the pathogen then die in large numbers. (pus is made up from the debris of neutrophils)

Mast cells

These cells produce and release histamines, they are found in the respiratory and gastrointestinal track.

Dendritic cells

Are phagocytes with membranous extensions that engulf pathogens, process them, then present them to other cells to allow for recognition to occur.

Antigen

A unique molecule or part of a molecule that initiates an immune response.

Self-antigen

A molecule that defines the cell as belonging to the organism.

Non-self-antigen

A molecule that is not recognised by the host cell as belonging.

Antibodies

Molecules produced by the lymphocytes to bind to specific antigens on pathogens preventing the action of the pathogen.

B lymphocytes (B - Cells)

They are capable of making antibodies when presented with a pathogen that they mark for engulfment and destruction by a phagocyte. They then activate and turn into plasma and memory cells.

Plasma Cells

Specialized to produce large amounts of antibodies to fight infection.

Memory B cells

They remember the antigens of the pathogens and respond to later infections. They live in the bone marrow. They are activated by b lymphocytes and produce antibody 'tags' to allow for the phagocytes to destroy the 'tagged' cell.

T lymphocytes (T - Cells)

Produced in the bone marrow and the thymus gland, they have antibody like molecules on their surface which bind with foreign antigens. There are 4 main types.

Helper T cells

Part of the T lymphocytes, they produce and release cytokines in response to antigens activation other immune cells.

Cytotoxic T cells

Part of the T lymphocytes, When stimulated they target foreign/infected cells and kill (lyse) them with lethal chemicals that they make.

Regulatory T cells

Part of the T lymphocytes, When the threat has passed they turn off or suppress the activity of the other cells.

Memory T cells

Part of the T lymphocytes, They have previously encountered and responded to the antigen, they can recognise foreign invaders and act like memory B cells. They do not 'tag' infected cells but signal effective killer T or cytotoxic cells to destroy the infected cell.