Immunity Flashcards
goal of the immune system
prevent foreign substances from entering the body
establish immunity or resistance to disease-causing agents through the immune response
help maintain the body in a healthy state
immune system triggers
antigen
haptens
major histocompatibility complexes (MHC)
antigens
triggers the immune response
large-molecular substances
proteins and polysaccharides
examples of antigens
chemicals
food proteins
products of microbes
microbes themselves
abnormal human tissue cells
donor tissue cells
persons own normal tissue cells
haptens
smaller-molecular weight substances that can only exhibit antigenic properties when combined with a larger human protein from the skin, blood or other tissue
examples of haptens
plant oils
medications
metals
major histocompatibility complexes
molecules of the surface of the cell used for coding the cell so that the body can recognize its own cells from others
changes by viruses will cause the MHC to become antigenic resulting in destruction of the cell
nonspecific immunity
called innate or natural immunity, provides generic defenses to protect the body and is made up of defense mechanisms that require no previous exposure to the agent to accomplish the goal of neutralizing it
examples of nonspecific immunity are
physical barriers
chemical barriers
nonspecific phagocytosis
indigenous microbes
inflammatory response
clotting system
complement and kinin systems
waldeyer ring
strategically placed mucosa-associated lymph tissues that detect and remove injurious substances before they compromise the defensive barrier
comprised of:
pharyngeal tonsils
palatine tonsils
lingual tonsils
specific immunity
called acquired immunity
works in conjunction with inflammatory, healing, and repair process in response to specific threats
acts against previously encountered agents with antibodies and activated lymphocytes that are specific for that agent
immune system response
organs associated with the immune system
bone marrow: produces cells of immune system from precursor stem cells, B lymphocytes and T lymphocytes
thymus: T cells go to Thymus to mature, self-tolerant, can recognize the hosts own cells as self
spleen: filters and removes old and damaged red blood cells from general circulation, will mount an immune response against any foreign substance presented to it via the same circulating blood
lymphatic vessels and nodes: initiate immune response, process some of the immune system cells, remove foreign substances from host through system of vessels and nodes placed throughout the body
mucosa-associated lymphoid tissue: detect and remove injurious substances before they compromise defensive lymph barrier, gastrointestinal, respiratory and genitourinary tracts
cellular and chemical components associated with the immune system
macrophages: related to inflammatory process, integral to both inflammatory and immune processes
B lymphocytes: most active in humoral immunity
T lymphocytes: most active in cell-mediated immunity, necessary for optimal functioning of humoral immunity
cytokines: interleukin 1, interleukin 2, tumor necrosis factor, interferon
goal of immune response
remove or neutralize antigenic substance
must recognize, react to, and remember the invader
humoral (outside of cell) and cell mediated (inside of cell)
humoral immunity
-provided by B cells
-targets extracellular pathogens and toxins
-B cells develop in bone marrow and mature in lymphoid tissue
-maturation ensures that surface contains antibody
-antigen binding fragment is part of antibody that binds with/to an antigen that it is suited for
-B cell becomes activated when the antigen binding agent comes in contact with the antigen it can bind to AND
-when a T Helper Cell binds to the B cell
-end product of activation is a transformation of the B cell to a lymphocyte known as a Plasma Cell
why do B and T cells need to function together
to form plasma cell that created antibodies
primary immune response
how long do plasma cells live for
only a few days
primary immune response
process of B cell activation also stimulates
the plasma cell to divide and become more numerous
stimulates marrow to make more B cells that can become plasma cells upon activation
primary immune response
primary immune response
slow production of antibodies at initial exposure
host showing signs/symptoms
memory B cell is created
secondary immune response
when memory cells come into contact with recognized antigen
memory B cells attack antigens
antibody actions against antigens
neutralize bacterial toxins
bind with viruses to prevent entrance into cells
cause the agglutination of antigens to facilitate phagocytosis
bind to the surfaces of the antigen to aid in phagocytosis
bind with an antigen to activate the complement system
immunoglobulins are a part of
saliva
5 main groups of immunoglobulins
IgG
IgM
IgA
IgE
IgD
immunoglobulins uses antibodies to neutralize _________ pathogens and toxins but cannot neutralize microbes residing and replicating ________ the cell
extra-cellular
within
cell mediated immunity
neutralizing microbes inside cells
destroys target cells
able to destroy tumor/cancer cells and damaged host cells
always lymphocytes: T lymphocytes, Natural Killer, Macrophages
t-lymphocytes
start in marrow from stem cells, move to thymus where they learn how to be self-tolerant and mature to be antigen specific
stored in lymphatic tissue
must be activated/sensitized to function
once presented with antigen, the T cell is activated against the antigen
cytokines called interleukins assist in the activation of the T cells
antigen presenting cells (APC), phagocytizes or binds to antigen and brings it to T cell
some T cells can live for long periods of time and maintain their antigenic specificity becoming T memory cells
T cell functions are determined by protein molecules carried on their surfaces called Clusters of Differentiation (CD)
common APC’s
macrophages
monocytes
B cells
two important types of CD
CD4+ or Helper T cells
CD8+ T or Cytotoxic cells
CD4+ or Helper T cells
regulate the action of all other cells of immune system
increase or enable the functioning of B cells, macrophages, NK cells and other T cells through release of cytokines
normally have twice as many CD4+ cells as CD8+ cells
CD8+ T or Cytotoxic cells
able to kill cells that have been recognized as antigenic
must be activated by helper T cell or a macrophage before it can destroy the antigen
active in tissue rejection
have a role in suppressing or stopping the immune response to a specific antigen
natural killer cells
similar to cytotoxic T cell
DO NOT need to be sensitized to that antigen before reacting to that antigen, can respond immediately
recognizes foreign substances without any input from other cells or chemical mediators
recognize and destroy virus infected cells, and abnormal cells
impaired in immune deficiency disorders
NK and cytotoxic T cells play a part in detecting and eliminating cancer cells before they multiply
macrophages
link between inflammatory process and immune system response
DO NOT need to be sensitized by antigen to recognize and destroy it
receptors on surface to recognize opsonized matter
can be activated to become even more destructive by chemical mediators released by CD4+ cells
activated macrophages
secrete more chemical mediators, have enhanced capabilities related to chemotaxis, phagocytosis, and antigen presentation
after macrophage destroys an antigen
it will present specific proteins from the antigen to a T lymphocyte, thereby activating the lymphocyte and starting the immune response
do macrophages retain memory of the antigen they destroyed
no, they need reactivation when they encounter same antigen
what does the non-specific nature of macrophages assist in
helping the immune system respond immediately to injurious agents
what does the cell-mediated immune response in macrophages do
results in destruction of target cells and/or activation of the humoral immune response
specific immunity
the immune system works through integrated efforts to help body mount an immediate response to antigen next time it is encountered, so that the host can avoid any pathology that the antigen would have caused
two types of specific immunity
active immunity
passive immunity
active immunity
produced by body in response to antigen
can happen naturally or through vaccination
produces long-term immunity due to creation of memory cells
vaccines contain either killed, or attenuated bacteria, virus, or chemically altered toxins
produces long-term immunity due to memory cells created in response to an antigen, these memory cells will reproduce for the life of the host
booster shots are to make sure memory stays strong
passive immunity
host does not have his or her own antibodies but is given antibodies from another source: human or animal
short lived, no B-cells activated in response to antigen
person still subject to infection
immunopathology
dysfunction or abnormal functioning of the immune system
hypersensitivity reactions, autoimmune diseases, immune deficiency diseases
hypersensitivity reactions
set immune system against host and become destructive to individual
four types of hypersensitivity reactions
type 1: Anaphylactic or Atopic Reactions
type 2: Cytotoxic Reactions
type 3: Immune Complex-Mediated Reactions
type 4: Cell-mediated or Delayed Hypersensitivity Reactions
urticaria
a swelling of superficial layers of skin and is itchy
angiodema
a swelling of deeper subcutaneous or submucosal tissue, NOT itchy
can cause airway obstruction
autoimmune diseases
when immune system loses ability to distinguish self from non-self or there is an alteration of the host’s cells that change their makeup
attacks the cells of host as if they were foreign matter
immune deficiency diseases
when immune system or part of it fails to function
not performing its duties
primary and secondary
primary immunodeficiency diseases
caused by genetic or congenital abnormality
defective functioning of at least one part of the persons immune system or inflammatory process
impairs hosts ability to fight infection
T cells may not function properly
two primary immunodeficiencies
selective immunoglobulin A deficiency
DiGeorge syndrome
secondary immunodeficiency diseases
acquired or develops after birth
not related to genetics
opportunistic infections
higher risk of periodontal disease
opportunistic infections
caused by organisms that usually pose no harm to a host with a normal immune system
signs that a DH might see in oral cavity of people with autoimmune diseases
pemphigus vulgaris
cicatricial pemphigoid
oral lichen planus
systemic lupus erythematous
