Lecture 11 Flashcards
The general systemic effects of infection is/are mediated by what acting humorally?
IL-1, 2 and 6 plus TNF.
Responses to infection include?
plasma FA’s, AA’s, WBC’s, cortisol, acute phase proteins and fever while food intake and appetite.
What do “activated” Helpers release to “turbocharge” macrophages and NK’s?
IL-2 and Interferon-gamma.
Allergy and hypersensitivity is associated with which type of antibody?
IgE
Immunization can be induced by injecting?
dead organisms no longer pathogenic but still antigenic, a live but “attenuated” organism that is no longer pathogenic but still antigenic and chemically-neutralized toxins which are still antigenic.
All lymphocytes are “programmed” to respond to one potential antigen only by “________” either in the bone marrow (B-lymphocytes) or in the thymus (T-lymphocytes
gene shuffling
After “programming” lymphocytes migrate to lymphoid tissues (lymph nodes primarily) where they wait to be activated by their ________ _________.
specific antigen
T or F? Helpers must be activated by an APC using the “double handshake”
True
T or F? APC’s include macrophages that phagocytize invading organisms, digest them and link them to MHC I proteins necessary to present and therefore activate Helpers: Dendritic cells also perform this function similarly
False, MHC II not MHC I
T or F? Macrophages and B-lymphocytes kill by phagocytosis.
False, B-lymphocytes only internalize via receptor-mediated endocytosis of surface-expressed immunoglobulins (Ig’s) binding their specific antigen
How are helper cells activated?
by their specific antigen presented using MHC II protein plus nonantigenic matching
T or F? Helper cells participate directly in antibody production and direct killing.
False, indirectly
_____________ T-lymphocytes can inhibit both Cytotoxic and Helper lymphocytes.and are activated by Helper secretions.
Suppressor
T or F? B-lymphocytes are “programmed” to respond to one specific antigen which fully activates them in lymphoid tissues by binding to a specific surface-expressed immunoglobulin.
False, partially
How are B-lymphocytes fully activated?
Full activation is only achieved if a specific Helper is also activated by the same antigen (by APC’s) and the appropriate cytokines secreted
Fully activated B-lymphocytes multiply and differentiate into ____ _____.
Plasma cells, which secrete the “free” circulating form of the immunoglobulin expressed on the original B-lymphocyte which then bind to the specific antigen (programming in bone marrow).
B-lymphocytes attack their targets via specific antibodies which have direct actions including:
- Agglutination and precipitation (antibodies have >2 binding sites* for same specific antigen)
- Neutralization.
- Lysis (“strain” on cell membrane due to multiple binding*).
Specific antibody binding recruits several potent additional mechanisms mediated via the “classic” Complement system including:
- opsonization (via factor C3b: but now specific as directed by a specific AB.)
- lysis via the MAC.
- agglutination after activated Complement factors alter invader’s external surface.
- neutralization of viruses.
- chemotaxis of neutrophils and macrophages enhancing innate responses (phagocytosis) but also lymphocyte
- activation as macrophages are APC’s.
- activation and chemotaxis of Mast cells and basophils, etc. giving an increased inflammation response.
- recruitment of NK cells
T or F? Cytotoxic T-lymphocytes seem to be primarily involved in destroying our own virus-infected or cancerous cells.
True
Viral protein or mutated protein must be presented via MHC I protein which all _____ cells possess; so infected/cancerous cells in effect “present themselves.
nucleated
Cytotoxic T-cells kill directly by punching holes in membranes (so similar to the MAC) via secreted ______ and secretion of ____ ______.
Perforins; cytotoxic chemicals
________ kill directly via cytotoxic chemicals and often act against our own virus-infected or cancerous cells.
NK Cells
T or F? NK utilizes the MHC I protein
False, they do not use any MHC proteins
How are NK cells fully activated?
They are fully activated by interleukin-2 from activated Helpers which also secrete interferon-gamma which stimulates their production of cytotoxic chemicals.
