Chapter 13 Terms Flashcards
(37 cards)
Adhesion Molecules (Families)
- Selectins
- Addressins
- Integrins
- Immunoglobulin Supergene Family
Adhesion Molecules
Their cell surface expression is upregulated or down regulated depending on the nature of the stimulatory signal & serves to bind or glue cells together temporarily.
Extravasation
A 4 step process where leukocytes migrate out of the blood vessels to underlying sites of inflammation.
4 Steps of Extravasation:
- Rolling adhesion
- Tight binding
- Diapedesis
- Migration
Humoral Immunity
Antibody-mediated immunity
Cell-Mediated Immunity
Does not involve antibodies, but rather involves the activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen.
Viruses
- Small infectious agents that replicates only inside the living cells of other organisms.
- Viruses can infect all types of life forms, from animals and plants to microorganisms, including bacteria and archaea.
Extracellular Bacteria
These organisms, once they are within the host, are constantly exposed to humoral host defenses (complement & antibodies) as well as becoming prey for phagoctes.
Extracellular Bacteria Examples:
- Staphylococcus
- Streptococcus
- Neisseria
- Bordetella
- Yersinia
Intracellular Bacteria
Pathogenic bacteria that normally invade human cells.
Intracellular Bacteria Examples:
- Mycobacteria
- Shigella
- Salmonella
- Listeria
- Rickettsia
- E. coli (can be both intra- & extracellular)
Protozoa
Can be either extracellular or intracellular within the host.
Fungi
Can trigger various immune responses, including the production of high levels of specific antifungal antibodies.
Worms
- Flatworms & Roundworms
- IgE-mediated type I hypersensitivites & cell-mediated DTH responses create inflammation at the site of infection that may disrupt or inhibit the anchoring of these worms to tissues such as the intestinal epithelium.
Evasion
Strategies to slip by the surveillance of the host immune system.
Evasive Techniques
- Genetic Drift
- Genetic Shift
Genetic Drift
- The change in the frequency of a gene variant (allele) in a population due to random sampling of organisms.
- Accounts for the frequent changes that occur in the influenza virus from on “flu season” to the next & for the high antigenic diversity that is found among HIV isolates within a single infected individual.
Genetic Shift
- Also seen in the influenza virus.
- Occurs when influenze viruses from different species infect the same cell.
Disruption
Various infectious agents secrete products that interfere with the immune responses generated against them.
Destruction
The ultimate act of resistence by an infectious agent against a host immune system is to destroy it.
Inflammation
Not a singular event; it is the composite of multiple immune responses elicited against a particular stimulus.
C-Reactive Protein (CRP)
- Readily binds to phosphocholine (a molecule expressed on some microbes) & acts as an opsonin.
- It is one of a set of serum proteins known as acute phase proteins that inhibit the spread of infectious organisms & also include complement components, type I interferons, fibronectin, & protease inhibitors.
Fever
Defined as having a temperature above the normal range due to an increase in the body’s temperature set-point.
Mucosa-Associated Lymphoid Tissue (MALT)
The part of the immune system associated with the mucosal surfaces is often thought of as a separate & independent part of the overall immune system.
