Unit 3 Exam Terms Flashcards
___________ is one of the few vaccines that is efficient even after the host has
already been _______ by the infectious agent
anti-rabbi, infected
Elie Metchnikoff
recognized the importance of phagocytes in defending against infection. He used starfish larvae as a model system. Also observed phagocyte movement towards bacteria.
Emil von Behring
developed “antitoxins” against both diphtheria and tetanus. They had injected diphtheria and tetanus toxins into guinea-pigs, goats and horses; when these animals developed immunity, they derived antitoxins (now we know are antibodies) from their serum.
Merrill W. Chase
- White blood cells, and not antibodies alone, were important instruments of the immune system.
- Chase’s findings laid the groundwork for later research that discovered the role of B (from Fabricious bag in birds and bone marrow in mammals) cells T cells (from Thymus)
Hematoxylin/eosin staining
Hematoxylin binds basophilic nucleic acids, staining them blue, and the acidic dye eosin binds eosinophilic proteins in granules and cytoplasm, staining them pink.
Percentage of cells in human blood
Myeloid Cells
Neutrophil 50-70%
Monocyte 2-12%
Eosinophil 1-3%
Basophil <1%
Mast Cell <1%
Lymphocytes
T Lymphocytes 7-24%
B Lymphocytes 1-10%
NETS- neutrophil extracellular traps
- NETosis: type of cellular death
- large strands of DNA release into local environment
- Cellular proteins associate with the nets
- defensins, proteases
Antigen-presenting cell (APC)?
- Some examples are macrophages and dendritic cells.
- Secrete proteins that attract and activate other immune cells (Cytokines and chemokines).
- Internalize pathogens via phagocytosis, digest pathogenic proteins into peptides, and then present these peptide antigens on their membrane surfaces via major histocompatibility complex (MHC) class II molecules.
- They upregulate costimulatory molecules required for optimal activation of helper T cells (e.g. cytokines).
Humoral immunity
aspect of immunity mediated by macromolecules found in extracellular fluids such as secreted antibodies, complement proteins, and certain antimicrobial peptides.
Effects of Cytokines can include: Pleiotropy, redundancy, synergy, and antagonism.
Pleiotropy = one cytokine produces multiple effects
Redundancy = more than one cytokine induces the same effect
Synergy = two (or more) cytokines work together to induce an effect
Antagonism = one cytokine can inactivate the effect of another
Cytokine- related diseases
- Inflammatory cytokine levels may be increased in disease states
- Septic shock: common and potentially lethal
- Bacterial toxic shock induced by superantigens
- Potential involvement in rheumatoid arthritis and Type 2 diabetes
- Implication in lymphoid and myeloid cancers
- 1918 H1N1 influenza pandemic and cytokine storms
- Evidence of cytokine involvement in severe acute respiratory syndrome (SARS and SARS-CoV2)
Cytokine-based therapies
If cytokine levels are related to disease, therapies to reduce cytokine levels can treat disease:
- Rheumatoid arthritis
- Multiple Sclerosis
- Prevention of transplantation rejection
N.B.
A large, oral dose of an immunogen may induce tolerance rather than immunity.
Listeria
Intracellular bacterium that resides in soil and can cause food-associated illness and fatalities
Escape from Phagosome (to escape killing)
tuberculosis
Major global problem as it is difficult to treat (3 antibiotics)
Very difficult for the immune system to deal with
Very problematic in areas with co-infection with HIV (deadly)
Lives inside the phagosome (prevents phagosome–lysosome fusion)
IFN-γ from T cells helps but IFN activation is also shut down
No effective antibody response–response is from effector T cells
