Virology Exam 3b Flashcards
first line of defense
physical barriers
second line of defense
intrinsic cellular defenses
third line of defense
immune response
innate immunity
rapid responses but nonspecific
adaptive immunity
responses that are slower but long-lasting and highly specific
inflammatory response
mediated by cytokines and migrating leukocytes (macrophages, neutrophils)
macrophages
- activated by infection and kill viruses or infected cells using toxic oxygen compounds
- come from same lineage of monocytes who are immature version of macrophages in blood
- located in tissue
- antibody-dependent cellular cytotoxicity
antibody-dependent cellular cytotoxicity
targets viruses that are covered in antibodies
natural killer cells
recognize virus-infected cells and kill them via apoptosis pathways
- reduced MHC expression causes perforin to lyse cells and granzyme B to activate apoptosis
neutralization
antibodies cover virus which doesn’t allow virus to connect to cells
reduction in the MHC occurs when…
the cell is infected by a virus
where does the development of blood cells occur?
in the bone marrow
what are the two branches of the adaptive immune system?
- humoral
- cellular
humoral immunity
deals with antibodies and circulates throughout the body,
TH2
cellular immunity
virus infected cells, cytotoxic T cells, TH1
B cell receptors
membrane bound antibodies that bind to epitopes on intact proteins
T cell receptors
bind to small peptide epitopes produced by intracellular digestion of proteins
clonal selection theory
these receptors are created in an antigen-independent manner
epitope
where the antibody binds to on the antigen
after first infection, how long does in take to see a response from our immune system?
one week
What do T lymphocytes respond to?
respond to peptides on surface of antigen-presenting cells
antigen-presenting cells
take up and digest antigens to display them on surface of MHC-II complexes
What do B lymphocytes respond to?
respond to antigens and are stimulated to differentiate to plasma cels by interaction with humoral cells
cytotoxic T cells
generated upon interaction of Tc cells with MHC bound peptides
effects of interferons on immune response
stimulate antigen processing and presentation
how do viruses evade innate immunity?
- prevention of complement binding to antibody/antigen complexes
- inhibiting NK and dendritic
- interferons
- cytokine-like proteins and receptors that interfere with host defenses
how do viruses evade adaptive immunity?
- change epitopes by antigenic drift
- antigenic shift
- block MHC-I antigen presentation
