Differences between innate and acquired immunity? Similarities?
-rapid response (hours)
-limited number of specificities
-constant during response
-slow response (days to weeks)
-highly selective specificities
-improve during response
-resolves infection usually
Similar -common effector mechanisms for destruction of pathogens
Besides infectious processes, what is the immune system involved in?
What is the immune system composed of?
-macrophages, monocytes, dendritic cells
What are the lymphoid cells? where are they produced? Function?
-made in bone marrow
-key in adaptive immunity (humoral)
-made in thymus
-key in adaptive immunity (humoral and cell mediated)
Describe the antigen receptors on B lymphocytes?
-have an antigen binding site-determines which cell responds, very specific
-light chain with binding site
-heavy chain which anchors molecule, goes through transmembrane region
Describe antigen receptors on T lymphocytes?
-antigen binding site, very specific
-alpha and beta chain
-variable region on top
-constant region on bottom
-anchored in transmembrane region
-less diverse, recognize linear molecules
Explain why B and T lymphocytes are important to adaptive immunity?
T -centrally important in most adaptive antigen specific immune responses
-made in thymus
B -make antibodies which can attack viruses or bacteria
What are antibodies? Where are they produced? Function? What do they look like?
-protein that binds specifically to an antigen
-produced by plasma cells (differentiated B cell) in response to infection or immunization
-binds to and neutralizes pathogen or prepares for destruction by phagocytes or complement
-look like B lymphocytes, but chains are connected by disulfide bonds
What are the major subsets of T cells? What do they regulate? Functions?
-regulate afferent (generation) and efferent (effecting the response) arms of many different types of response
-generate cell mediated and humoral responses
-Regulatory T cells
-cytolytic T cells
-cytotoxic or cytolytic for cells bearing relevant antigen
-regulates immune responses (suppression)
Functions of B lymphocyte, Helper T lymphocytes, Cytotoxic T lymphocytes, Regulatory T lymphocytes?
B -make antibodies
-neutralize microbes, phagocytosis, complement activation
Helper T -make cytokines
-activation of T and B lymph
Cytotoxic T -kill infected cells
Regulatory T -Suppress other lymphocytes
What are the types of specific immunity? Specificity? Memory?
-generate a response
-natural via infection
-artificial via vaccination
-natural by transplacental or colostral transfer of antibody
-artificial by administration of immune globulins
Adoptive -transfer of immune cells
What activates natural killer cells (NK)?
when a virus inhibits class 1 MHC expression
What are natural killer cells? Function?
-clear virally infected cells
-clear tumor cells
-effector in natural immunity
-act in same time frame as innate
-faster than B and T cells
-may enhance inflammation
-phagocytosis of extracellular microorganisms and viruses
What are the two subsets of NK cells? Function? Where found?
CD56 dim -make up 90% of NK cells in blood
-enhanced cell killing capacity
CD56 bright -make up 90% of NK cells in tissues
-enhanced growth factor and non inflammatory cytokines
What leukocytes have the biggest proportion in human blood?
What are the cardinal features of adaptive immune response?
-discrimination of self and non self
Cardinal features: specificity?
-an immune response is specific for distinct antigens
-function of distinct antigen receptors on the lymphocyte surface
-antigen receptors present before exposure to antigen
-basis of clonal selection theory
Cardinal features: diversity?
-total number of antigenic specificities of lymphocytes in an individual is large
-individual can discriminate at least 1 billion different antigens
-result of incredible variability in the antigen receptors among lymphocytes
Cardinal features: adaptability?
ability to respond to antigens not previously encountered in nature
Cardinal features: memory?
-exposure of the immune system to foreign antigen enhances its ability to respond again
-secondary immune responses are more rapid, bigger, qualitatively different
Cardinal features: self limitation?
-immune response wanes with time because of the elimination of antigen, effector cells are short lived, regulatory feedback elements of immune response
Clonal selection theory?
-every individual contains numerous clonally derived lymphocytes
-each lymphocyte has an antigen receptor specific for a single antigen
-these are present prior to exposure to antigen
-antigen selects a pre existing clone and activates it
What is the architecture of a lymph node? where do T cells and B cells congregate?
T cells- in center
B cells- outer
What is the difference between the primary and secondary immune response to the same antigen?