INTRODUCTION (Innate-Adaptive Immunity) Flashcards
Primary function of the Immune System
- Surveillance and destruction of substances that are foreign to the body (other substances that are foreign to the bodies are also eliminated by the immune system)
- Recognize self from nonself and to defend the body against nonself
The immune system is divided into:
Innate and Adaptive Immunity
Both Innate and Adaptive Immunity are further subdivided into:
Humoral and Cellular Immunity
Deals with the substances usually proteins that are present in the body fluids
Humoral Immunity
The cellular aspect of immunity deals with the cells
Celllular Immunity
When an antigen enters the body then it is the first exposure, if the same antigen reaches the immune system of the body. Its response does not change from the previous exposure to that certain antigen.
Innate Immunity
Ability of the individual to resist infection by means of normally present body functions
Innate Immunity
Refers primarily to anatomical, cellular, and humoral defenses. Natural immunity (inborn or innate resistance)
Innate Immunity
Identify:
- Do not possess immunologic memory
- Nonspecific
- Consist of : Anatomic Barriers, resident flora, humoral factors, cells
Innate Immunity
Identify:
- Has memory
- Specific
- Consist of: lymphocytes (T cell & B cell) antibodies and cytokines
Adaptive Immunity
This defense mechanism has no specicity and they limit the entry of all pathogens in respective of which one is trying to reach the integrity of the body
External Defense System
Examples of External Defense System
Structural barriers and anatomical barriers (such as skin, mucous membranes, cilia, resident flora)
Innate Immunity is composed of:
- External Defense System
- Internal defense system (consists of Humoral and cellular factors)
It is designed the keep the microorganism from entering the body. They are structural barriers that prevent most infectious agent from entering the body
External Defense System
Present in respiratory tract epithelium
Cilia
They prevent the colonization of new microorganisms because the newmicroorganism cannot establish themselves in the region where othermicrobes are already thriving
Resident flora
Resident flora are non-pathogenic bacteria of the?
intestines, vagina, and nasopharynx
These play an essential part in the Internal defense system/mechanism
Cells and soluble factors
It is designed to recognize the molecules that are unique to infection organism
Internal defense system/mechanism
They are immunologic substances that are present in the body fluids and can be categorized to humoral and cellular factor
Internal defense system/mechanism
Examples of 1humoral factors:
- Lysozyme
- Lactoferrin
- Pepsins
- Stomach acidity
- Complement
Present in tears, sebaceous, and sweat gland secretions that will cleave the cell wall of bacteria
Lysozyme
Present in tears, sebaceous and sweat glands secretions and it will bind iron which is an essential growth molecule for bacteria or microbes restricting the amount of iron that is essential for the growth of bacteria
Lactoferrin
Present in stomach which will digest bacterial surface protein and that wouldbind to cells that are present in the intestinal laminae
Pepsins
Provide host defense because many organisms cannot survive the acidic environment of the stomach and they are destroyed before entering the small intestine.
Stomach acidity
Made up of family of proteins (around 30 proteins) whose coordinated actions will lead to the destruction of microorganisms particularly the extracellular bacteria
Complement
Complement are present in?
Blood, lymph and interstial fluid
Some complement proteins can facilitate phagocytosis while others will penetrate bacterial membrane and cause lysis to the bacterium so that specically goes to membrane attack complex
Complement
For proteins that will facilitate phagocytosis are the opsonins
Complement
Cells that are present in the bone marrow (bone marrow derived cells). They are recruited when the initial barriers have been breach and antigens sub succeeded in entering thebody
Cellular defense
Cells of innate immunity consist primarily of:
- Phagocytes
- Natural killer cells
- Eosinophils
- Antigen Presenting Cells (APC)
- Mast Cells
- Basophils
Cells that will engulf and destroy foreign substances and microorganism
Phagocytes
Eliminate virally infected cells
Natural killer cells
Elliminates helmints
Eosinophils
These cells will present the antigenic fragments from processing it then present the fragments to one group of cells that will function in the adaptive immune system
Antigen Presenting Cells (APC)
Both are important in host defense because they will release substances into the local micro-environment that can facilitate recruitment of immune cells to the site of infection.
Mast cells and Basophils
They are derived from self renewing precursor cells that will differentiate to progenitor cells from which myeloid and lymphoid cell lineages will arise
Cells of both innate and adaptive immunity
Myeloid progenitor cells will give rise to?
neutrophils, monocytes and basophils and eosinophils
Give rise to naive mature B cells. These are cells that have not been antigenically stimulated
Lymphoid progenitor cells
Full differentation will occur in thymus
Precursor T cells
Primary lymphoid organs:
Bone marrow (B cells) and Thymus (T cells)
Immune cells undergo maturation, and/or differentiation, and proliferation
Lymphoid organs
Primary lymphoid organs in birds. It is where B lymphocytes would mature and bring about humoral immunity but in humans it is in the bone marrow.
Bursa of Fabrio’s
Site where progenitor cells will dierentiate into T cells and B cells
Primary lymphoid organs
Immune cells mature in?
Bone marrow and thymus
Cells in primary lymphoid tissue does not come in contact with?
foreign antigen
Bursa equivalent of the maturation of B cells
Bone marrow (B cells)
The bone marrow is the site where blood cells originate and undergo some, if not all, aspects of maturation
Hematopoiesis
Key feature of _________ is the rearrangement of the genes that encode the receptor that will recognize foreign antigen, but not self molecules
B cell maturation
Receptors of the Bone marrow (B cells) are membrane bound antibodies, more often referred to as?
membrane immunoglobulins
Recognize antigen present on the surface of antigen presenting cells orinfected cells
T cell receptor
Most signicant aspect of __________ is the rearrangement of genesegments that encode the receptor
T cell maturation
Mature T cells leave the (1) _________, enter the (2)__________, and either seed the (3) ___________ or circulate in immuno surveillance
(1) thymic medulla; (2) blood stream; (3) secondary lymphoid tissues
Increases in size until it reaches its peak development during adolescence
T cells
Bone marrow derived precursor T cells will migrate inside the _______ where they will undergo maturation
cortex
T cells in thymus are called?
thymocytes
Has a connective tissue capsule (dark brown color), extends inside gland, divides into lobule
Thymus (T cells)
Thymus (T cells) are divided into lobules, namely:
- Cortex (precursor cell migrates here and Maturation)
- Medulla (inside; middle)
First exposure of antigen will initiate immune response in B side
Secondary lymphoid organs
Secondary lymphoid organs:
- Spleen
- Lymph nodes
- Mucosa-associated lymphoid tissue (MALT)
Large lymphoid organ, is surrounded by _________ that penetrates and divides the spleen into incomplete compartments
connective tissue
The (1) __________ contains primarily T cells, the (2) _______ contain B cells; while the (3) _________ contains dendritic cells and macrophages, as well as CD4+ Tcells and B cells.
(1) periarterial lymphatic sheath; (2) follicles; (3) marginal zone
Lymphoid tissue of the spleen and includes the periarterial lymphatic sheath
White pulp
Located at the junction of main lymphatic tracts, small, encapsulated structures
Lymph nodes
Under white pulp, it contains T cells
PALS
Under white pulp, it contains B cells
Follicles
Under white pulp, it contains dendritic cells and macrophages, CD4+ T cells and B cells
Marginal zone
Antigens and cells present in the lymph enter the lymph nodes via _________ percolate through the node, and exit via the _________
afferent lymphatics: efferent lymphatics
In the absence of antigenic stimulation, lymphoid follicles are referred to as __________
primary follicles
These are small, and the cells within them are quiescent
primary follicles
_____ activation and proliferation in the follicles generates germinal centers, the site where they undergo differentiation processes is required for effective immune responses
B cell
B cells outer cortex (follicles)
Cortex (lymph nodes)
T cells (lymph nodes)
Paracortex
Macrophages (lymph nodes)
Medulla
Germinal centers (lymph nodes)
Secondary follicles
Compartments of the lymph nodes
- Cortex
- Paracortex
- Medulla
- Primary follicles
- Secondary follicles
Consist of diusely distributed lymphoid cells and follicles that underlie all regionscoated with mucosa.
Mucosa-associated lymphoid tissue (MALT)
The same immune cells are present in the MALT tissues as are present in the ____________
spleen & lymph nodes
A major component of GALT in the small intestine
Peyer’s patches
Identify:
- All regions with mucosa
- Similar immune cells
- Scatter diffusely
Mucosa-associated lymphoid tissue (MALT)
Lies below the skin
Cutenous immune system
Macrophage found in the blood is called?
Monocyte
Macrophage found in the bone marrow is called?
Promonocyte + Monocyte
Macrophage found in the CNS is called?
Microglial cell
Macrophage found in the kidney is called?
Mesangial cell
Macrophage found in the liver is called?
kupffer cell
Macrophage found in the lung is called?
alveolar macrophage
Macrophage found in the lymph node is called?
lymph node macrophage
Macrophage found in the spleen is called?
spleenic macrophage
Engulf and degrade antigens
Phagocytes
Immature precursor of the macrophage arises from bone marrow cells and is released into circulation. Although it has some phagocytic capability, it is not as effective in this role as its mature form
Monocyte
Leave the circulation and entertissues, where they differentiate into macrophages.
Monocyte
Identify:
Synthesis of biologically active molecules (cytokines) which can as well as elimination of antigen. May function as antigen presenting cells
Macrophage
Enhance or down regulate immune responses by acting in an autocrine (samecell) or a paracrine (other cells) fashion.
Cytokines
Receptor for TNF
Macrophage
Express a number of receptors, including cytokine receptors and receptors for opsonins
Macrophage
Express receptors for IFNy and TNF, cytokines that enhance itscytotoxic potential.
Macrophage
Short-lived circulating polymorphonuclear leukocytes whose main rolein host defense is phagocytosis.
Neutrophils
Under the influence of _________ neutrophils are recruited to the site of infection, where they phagocytose microbes
chemotactic molecules
Its main role is phagocytosis, it recognizes antigen through primitive pattern recognition or due to opsonins
Neutrophils
Neutrophils destroys antigen thru:
- Phagolysosome
- Respiratory burst
- Nitric Oxide
Produced by IFNy-activated macrophages, is toxic to organisms and constitutes the third mechanism by which antigens are destroyed within the macrophage.
Nitric Oxide
The second source of cytotoxic molecules results from the activation of an enzymatic complex, ____________, which is present in the phagosome membrane
NADPH oxidase
First involves the fusion of cytosolic lysosomes with the phagosome, which results from the formation of a chimeric vacuole called phagolysosome.
Antibody-dependent cell mediated cytotoxicity (ADCC)
ADCC leads to the release of the lysosomal contents, including _______, ________, and ________ into the phagosome.
defensins, lactoferrin, and lysozyme
Activation oxidase, which is present of NADPH oxidase leads in the to the production of the reactive oxygen intermediates, (1) __________, (2) ____________, and (3)___________, all of which are cytotoxic for microorganism
(1) superoxide anion (02“); (2) hydrogen peroxide (H202); (3) hydroxyl radicals (OH*)
Endocytose antigens, degrade, and display antigen fragments on the cell surface
Antigen presenting cells (dendritic cells)
Examples of APC:
- Dendritic cells (Most effective)
- Macrophages
- B cells
Circulation and secondary lymphoid tissues. Host defense against viral infections and some tumors
Natural killer cells (NK-cells)
Express cell surface receptors (FcyR). Can target and destroy some cells in the absence of IgG
Natural killer cells (NK-cells)
Viral proteins that remain embedded in the infected cell membrane when the virus budsfrom the cell provide a target for?
antibodies
The interaction of the natural killer cell with antibody on the cell target triggers the release of ________, a molecule that inserts into the infected cell
perforin
Several copies of this protein polymerize in the membrane to form a pore, and in doing so cause osmotic lysis of the infected cell, this mode of killing is called?
Antibody dependent cell mediatedcytotoxicity (ADCC)
Osmotic lysis of the infected cell occurs only if the natural killer cell does not receive an inhibitory signal via the?
killer inhibitory receptor (KIR)
Usually seen in hypersensitivity reactions including: allergy, asthma, anaphylaxis
Basophils & Mast cells
These have similar biologic roles
Basophils & Mast cells
Found in:
- Connective tissues
- Gastrointestinal tract
- Blood vessels
- Epithelium
Mast cells
Play a major role in immune responses following the activation ofcomplement.
Mast cells
Leads to the production of small amounts of anaphylatoxins (C3a, C4a,and C5a) which bind to mast cells and induce their degranulation and release of inflammatory mediators that include histamine.
Complement activation
Increases vascular permeability and this facilitates the recruitment ofcells from the circulation into the infected tissue
Histamine
When these mediators are released in excessive amounts, an enormous hypersensitivity reaction occurs. This exaggerated hypersensitivity reaction is called ________ and can lead to death
Less exaggerated responses can cause ________
anaphylaxis; allergies and/or asthma
Identify:
- Major basic protein
- Detect helminths
- Cationic protein
Eosinophils
Another molecule binds the antigen (opsonin)
Indirect recognition
Antigen is interacting directly with a receptor present on the cell
Direct recognition
The _______ serves as a link between the cell and the antigen. _________ on phagocytesare specic for different opsonins.
opsonin; Receptors
Component of the immune system that adapts depending on the antigens that it encounters
Acquired or adaptive immunity
A type of resistance that is characterized by specifty and memory
Acquired or adaptive immunity
Adaptive immunity is composed of:
Cellular & Humoral components
Because of the condition of recall or acquired resistance, it allows the host to respond more respectively if reinfection of the same microorganism occur
Acquired or adaptive immunity
Cellular adaptive immunity is composed of:
- Lymphocytes
- B cells
- T cells
Fill in the blanks:
The characteristics of the lymphocytes that function in adaptive immunity are:
(1) Their _________are specific for a particular segment of an antigen, and
(2) once lymphocytes have been activated in response to antigen, they will respond much faster upon subsequent exposure. This characteristic is referred to as ________
(1) cell surface receptors
(2) memory
The antigen specific receptor for _____ are commonly referred to as membrane antibody or membrane immunoglobulin
B cells
When B cells become activated it becomes either:
Memory B cells or Plasma cells
Produce antibodies. They secrete antibodies instead of expressing them on the cell surface
Plasma cells
Two types of T cells
Helper T cells and Cytotoxic T cells
Secrete soluble proteins or humoral factors known as cytokines (helper1 cytokines)
Helper T cells
Required for a virtually all aspect of adaptive immune response. They will kill virally infected host cells
T cells
Proteins that are secreted by the cell of adaptive immune system
Humoral adaptive immunity
The major humoral component
B cells antibodies
It refers primarily to cytokines produce by helper T cells
T cells
