Adaptive Immunity 2 Flashcards
what do B cells communicate with?
T cells
what do B cells produce?
antibodies
what does clonal expansion lead to?
generation of two subsets
what are plasma cells?
great big antibody factories
why are memory B cells important?
to mount a quicker antibody response to any subsequent infections
where do B cells mature?
in the bone marrow
where are B cells found?
they circulate in the blood and lymph and are found in large numbers in lymphoid organs
how do B cells recognise antigens?
through B cell receptor (BCR) which is the actual antibody (IgM or IgD)
what does diversity in BCR mean?
potential to respond to numerous antigens
once B cells are activated what do they change into?
plasma cells (antibody factories)
what are the three main receptors of adaptive immunity?
T cell receptor, B cell receptor and MHC
what does multiple genes encoding allow?
the development of a repertoire of receptors with wide specificity
which immunoglobulins can be B cell receptors?
IgM or IgD
what are the five different immunoglobulins produced by B cells
IgG, IgE, IgD, IgM and IgA
what is the most prominent antibody in the human body?
IgG
how many subsets can IgG be divided into?
4
how many subsets can IgA be divided into?
2
what is IgM capable of doing?
binding multiple antigens
what are the regions of B cell receptors?
constant and variable
what are the chains that B cell antibodies have?
light and heavy chains
what are the three main functions for antibodies in the human body?
neutralisation, opsonisation and initiation of complement
what is the primary goal of antibodies?
to prevent microbial activity and aid removal of threat from host
what is opsonisation?
the coating of pathogens by antibodies or complement proteins
what can opsonisation of pathogens by antibodies lead to?
phagocytosis, antibody dependent cellular cytotoxicity, mast cell degranulation
what complement pathway do antibodies initiate?
classical
what is the steps of antibody depended cellular cytotoxicity?
antibodies bind antigens on the surface of target cells, NK cell CD16 Fc receptors recognise cell-bound antibodies, cross-linking of CD16 triggers degranulation into a lytic synapse, tumour cells die by apoptosis
which antibodies give the greatest response in the classical pathway?
IgG and IgM
what is each B cell development stage defined by?
rearrangements of the immunoglobulin heavy and light chain genes
where do B cells go once they are in the periphery?
they migrate to secondary lymphoid organs
what does B cell development generate?
diversity
what are the steps of B cell development from being a stem cell?
stem cell - lymphoid progenitor - pro-B cell - early pre-B cell - late pre-B cell - immture B cell - mature B cell - either plasma cell OR memory B cell
what must the B cell be to be in the periphery?
mature
what genes does the heavy chain involve?
V, D, J
what genes does the light chain involve?
V and J
what is the main immature B cell receptor?
IgM
what receptors do mature B cells express?
IgM and IgD
where are IgM and IgD found on mature B cells?
the surface
what type of selection do B cells go and whereabouts?
negative selection in the bone marrow
what happens to self-reacting B cells?
macrophages engulf and remove them
what does selection ensure?
that there is no reactivity against self antigens
what are the major functions of antibody?
prevention of microbial adhesion, activation of complement, neutralisation of toxin, opsonisation to promote phagocytosis
what does diversity of antibody specificity involve?
gene-rearrangements during development