lecture 5 Flashcards
what are the properties to adaptive immune response?
specificity, diversity, memory, clonal expansion, specialization, contraction and homeostasis, nonreactivity to self
what are examples of the immune system cells?
T and B cells are lymphocytes
dendritic cells, macrophages, B cells, and follilcular dendritic cells are antigen presenting cells
lymphocytes, granulocytes (neutrophils, eosinophils) and macrophages are effector cells
what is humoral adapative immune response?
antibodies that circulate in blood, can recognize the infected cells and free microbes
cellular adaptive immune response?
lymphocytes t cells dont produce a soluble product, t cells can recognize the infected cells but not free microbes
which lymphocyte is the membrane bound antibody?
the B cell antigen receptor is membrane bound, surface immunoglobulin. T cell is not, t cell antigen receptor
what are the small antigen fragments bound to in t cells?
normal cell surface proteins called MHC molecules
what is antigen presentation?
when infected cells produce mhcs that bind to antigen fragments and are transported to the cell surface
what are some central lymphoid organs?
thymus- t cell maturation, bone marrow- b cell maturation
what are some peripheral lymphoid organs?
lymph nodes, spleen white pulp, mucosa associated lymphoid tissue- t and b cell activation, antigen trapping
what is acquired immunity?
the adaptive immunity provided by immunological memory
what are the effects of b lymphocyte?
neutralization of microbe, phagocytosis, complement activation, production of plasma cells
effects of helper t lymphocytes?
activation of macrophages, inflammation, activation of t and b lymphocytes
cytotoxic lymphocyte effects?
killing the infected cell, virus cells
what are the two instances where antibodies dont work well?
dont work well with hiv and intracellular pathogens
what does clonal selection of B cells generate?
a clone of short live activated effector cells and a clone of long lived memory cells
clonal selection theory accounts for…
diversity, self/non self discrimination, and memory
what is the make up of immunoglobulins?
2 heavy chains, 2 light chains, Fab, Fc where antibodies are defined
describe the 5 classes of antibodies
IgD-unknown,
IgG-major form of antibody circulating in blood,
IgM-memrbane bound formis the receptor on B cells, also circulates in blood
IgE-involved in allergic reactions and defense against parasites
IgA-found in secretions, first line of defense against pathogens
difference between IgG and M
M primarily activator in complement system. G can do that too but can play further effector mechanisms through Fc on phagocytes, eosinophils and mast cells
how is antibody diversity created?
B cells start off with same DNA as any other cell, as B cells mature the antibody DNA changes, heavy chain variable region encoded in 3 gene segments (V D and KJ), light chain variable region encoded in 2 gene segments (V and J), mix and match at random
steps to B cell maturation
immature b cell has not rearranged DNA for B cell receptor, naive b cell expresses a membrane bound antibody on its surface but hasnt encountered antigen, mature b cell undergone class switching, affinity maturation, and secretes an affinity matured antibody
what can antibodies do?
can block entry of a microbe into a host cell or prevent virus from replicating, can tag invaders for destruction, DONT directly kill anything
how are some ways pathogens evade antibodies?
change one antigen residue to prevent binding, mutate rapidly so antibodies dont react with new strain, and enter a cell so antibodies cant do anything
how are monoclonal antibodies used in medicine?
used to detect presence and or quantity of an antigen, used to purify antigens, increasingly used for medical applications like cancer
