Antibodies and more immunology Flashcards
Phagocytosis Step 1: Chemotaxis
Chemical attraction of phagocytes to microorganisms Microbial products (peptidoglaycan, LPS) Damaged tissue Cytokines Complement components
Phagocytosis Step 2: Adherence
Attachment of phagocytic membrane to microorganisms or foreign material
Phagocyte receptors - Toll like receptors (TLRs) +Microbe - Pathogen/Danger associated molecular pattern (PAMP or DAMP) Eg. LPS, Peptidoglycan
Phagocytosis Step 3: Ingestion
Pseudopods engulf the organism and form phagosome or phagocytic vehicle
Phagocytosis Step 4: Digestion
In the cytoplasm Phagosome fuses with in lysosome - Phagolysosome
Lysosomal enzymes
Lysozyme, lipase, protease, nuclease
Toxic oxygen radicals through oxidative burst
Myeloperoxidase
Superoxide dismutase
Phagocytosis Step 5: Elimination
Residual body
Inflammation
Second line of defense
Can be caused by microbes, physical and chemical agents
Host response to tissue damage
Serves to destroy the infectious agent, to confine it, and repair or replace the damage tissue
What are the cardinal signs of inflammation?
Redness, pain, heat, swelling, loss of function
Intense inflammation and for short periods of time is what kind of inflammation?
Acute inflammation
Chronic inflammation is?
Less intense and long lasting inflamation
What are the effects of inflammation?
Destroy or limit infection
Repair the damage tissue
Fever
Hypothalamus control body temperature
During infection, products of microbes induce the release of cytokines such as interleukin-1 which is an endogenous pyrogen
Antimicrobial substances
Complement
Interferons
Iron binding proteins
Antimicrobial peptides
Complement
A group of >30 proteins activated as a cascade by a pathogen or by an antigen antibody reaction
Complement together action of these proteins destroy microbes by
Enhanced Phagocytosis
Inflammation
Cytolysis
What are the three complement pathways?
Classical Pathway
Alternate Pathway
Lectin Pathway
Complement classical pathway
Initiated by antigen antibody complexes
Initiated by the interaction between C3, factors B, D and P and the pathogen is what pathway
Complement alternate pathway
Complement Lectin Pathway
Mannose binding lectin binds to Mannose on the surface of the microbes
The end result of the complement cascade is?
Membrane attack complex
Opsonin
Coats microbes and enhance phagocytosis (C3b)
Anaphylatoxins
Induce release of histamine and result in severe allergic reactions (C3a, C5a)
Membrane attack complex
Polymerisation of C5-C9
Complement
C1-C9 with C3 being the most critical
What is interferon?
A cytokine produced by virus infected cells, lymphocytes
What are the three types if interferons?
Interferon alpha
Interferon beta
Interferon gamma
Iron binding proteins
In the body iron is bound to molecules such as transferrin, lactoferrin, ferritin, hemoglobin
Bacteria that contain siderophores do what?
Sequester iron form the body
Which bacteria is more virulent? Ones with or without siderophores?
With siderophores
What line of defense is Adaptive immune responses?
Third line of defense
Is adaptive immune response specific or nonspecific?
Specific
What is adaptive immunity?
Specific immune response induced against a specific pathogen
What are the dual nature of adaptive immunity?
Humortal response - Antibody
Cell mediated response - T cells
What is an antigen?
Proteins that induce antibody response
What is the specific region of an antigen which interacts with antibody
Epitopes (antigenic determinants)
What is Hapten?
Low molecular weight compounds which can not induce an antibody response by itself
Attach to a carrier molecule to induce antibody response
What are antibodies?
Proteins called immunoglobulins. Produced by a B cell. One antibody molecule has two identical antigen binding sites which binds to antigen epitopes
What is valence?
the number of antigen binding sites in an antibody
