Venketaraman- Host Defenses Flashcards
innate immunity cells are pre-formed, and non-specific. but is it true/false that they lack immunological memory and do not improve over time?
true
what type of innate defense cell is non-phagocytic?
natural killer cells
which type of immunity (innate or adaptive) is slower onset but is highly effective once active?
adaptive immunity
do T lymphocytes produce antibodies and immunoglobulin?
no… they produce cytokines and interleukin
what antigen do dendritic cells contain on their surface?
CD14
what type of cell is capable of phagocytosis and pinocytosis?
Dendritic cells
what type of immunity presents antigens to CD4-positive helper T cells?
acquired immunity
what three things are generated when microbes are phagocytosed by monocytes and neutrophils?
reactive oxygen and nitrogen intermediates and antimicrobial peptides
when does fusion between phagosome containing microbes with lysosome occur?
when monocytes and neutrophils carry out phagocytosis
Complement proteins are mainly inactive in the blood. What leads to their activation?
antigen-antibody reactions, release of lipopolysaccharide (LPS) or release of mannose (carbohydrate)
what is the classical pathway of antigen-antibody reactions?
leads to the complex binding to the bacterial cell surface causing lysis of the bacteria
what pathway leads to the release of LPS from gram negative bacteria?
alternate pathway
Which cells phagocytotic activity are enhanced by the interaction of complement proteins with antibodies? And what is the process called?
neutrophils and monocytes.
opsonisation
in order of natural killer cells to lyse their target what needs to down regulated on the target?
MHC class I
what is the purpose of Toll like receptors (TLRs)?
they recognize LPS (TLR4) from gram negative bacteria and peptidoglycan (TLR2) from gram positive bacteria
what is the purpose of pro-inflammatory cytokines?
to induce liver cells to produce C-reactive proteins and also attract cells to site of infection leading to inflammation and cell death
Do T cells differentiate in the bone marrow?
nope… they differentiate in the thymus
what are the three steps in adaptive immunity (T cell response)?
antigen recognition, activation and response
both antigens and haptens are able to bind to antibodies, but which one cannot produce antibodies independently (without carrier protein)?
haptens
Do all T cells express CD4?
No, they all express CD3. (CD4 is only expressed by helper T cells)
What produces cytokines like interferon-gamma that can activate macrophages and neutrophils to control intracellular infrection?
Helper T cells
what type of T cell binds to dendritic cells in association with MHC I?
cytotoxic (CD8) T cells. these cells lead to cell lysis
What causes B cells to produce IgM?
Binding of LPS and other non-protein antigens to IgD on the surface of the B cells
