chpt 1 2
Terms
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- effector response
- appropriate response of various cells/molecules to recognition of a foreign organism in order to neutralize or eliminate the pathogen.
- memory response
- secondary exposure to foreign organism; more rapid, heightened immune reaction to eliminate pathogen and prevent disease
- immunis
- exempt
- immunity
- state of protection from infectious disease
- attenuated
- weakened
- vaccine
- a weakened (attenuated) strain of vaccine is injected into organism to confer resistance to later infection
- serum
- the liquid, noncellular component of coagulated blood
- Immunoglobulin
- fraction of serum that neutralizes toxins, precipitates toxins, and agglutinates bacteria. active molecules in IG fraction: antibodies
- Antibody
- the active molecule in immunoglobulin fraction of serum
- Why call it Humoral Immunity?
- because it's mediated by antibodies which are in the body fluid - serum.
- phagocytes
- white blood cells that ingest microorganisms and foreign material.
- Theory of cell-mediated immunity
- cells like phagocytes, not molecules like antibodies in the serum, are responsible for immunity
- Lymphocyte responsible for:
- both cellular and humoral immunity
- antigen
- foreign material that binds with specific antibody
- clonal selection theory
-
-lymphocytes express specific membrane receptors
-specificity is determined before exposure to antigen
-Ag binding to receptor activates lymphocyte - it proliferates. - Innate Immunity
-
first line of defense against infection; less specific immunity.
-components are present prior to infection, for PREVENTION - Adaptive Immunity
-
Specific;
Only starts if there is ANTIGENIC challenge.
-Special property: MEMORY
-Responds to first exposure to Ag in 5-6 days usually.
-Second response is better and faster. - 4 Barriers of Defense in Innate Immunity
-
-Anatomic
-Physiologic
-Phagocytic
-Inflammatory - Anatomic barriers of Innate immunity
-
Skin:
-mechanical barrier (epidermis, dermis)
-acidic pH bars microbial growth (sebum)
Mucous Membranes:
-line conjunctivae, alimentary, respiratory, urogenital tracts
-mucus traps foreign particles.
-cilia moves them out.
-normal flora outcompete pathogens for attachment sites. - fimbrae/pili
-
hairlike protrusions on bacterium that allow them to adhere to glycoproteins/lipids on particular epithelial cells of mucous membranes.
-method of defeating innate immunity - Physiologic barriers of innate immunity
-
Temperature:
-Body temp inhibits some pathogens
-Fever response does too
Low pH:
-Stomach acid kills ingested pathogens
Chemical mediators:
-Lysozyme, Interferon, Complement, TLR, Collectins - Phagocytic/endocytic barriers of innate immunity
-
Cells endocytose/break down foreign macromolecules.
Special phagocytic cells kill and digest whole microorganisms. - Inflammatory Barrier of Innate Immunity
- Tissue Damage or Infection induces leakage of vascular fluid which contains antibacterial serum proteins and phagocytic cells.
- Lysozyme
- cleaves peptidoglycan layer of bacterial cell wall; part of innate immunity, physiological barrier
- Interferon
- produced by virus-infected cells to induce antiviral state
- complement
-
serum proteins circulating in inactive state.
When activated, damage membranes of pathogenic organisms.
-Collectins are an example - Pattern recognition
-
-ability to recognize a given class of molecules.
-for innate immunity, these are molecules that are never found in eukaryotes so must be foreign. - Phagocytosis in Innate Immunity is conducted by:
- Blood Monocytes, Neutrophils, Tissue Macrophages.
- primary lymphoid organs
- provide the right environment for lymphocytes to develop and mature in
- secondary lymphoid organs
- trap antigen from defined tissues/vascular spaces; The sites where adult lymphocytes interact with the antigens.
- leukocytes
- white blood cells
- lymphocytes
- the leukocytes of adaptive immunity.
- HSC (hematopoietic stem cell)
- the cell that gives rise to all blood cells!!!
- stem cells
- cells that can differentiate into other cell types; multiply by cell division