Acquired Immunity Flashcards
Differences between innate and acquired immunity? Similarities?
Innate:
- rapid response (hours)
- fixed, broad
- limited number of specificities
- constant during response
Acquired:
- slow response (days to weeks)
- variable
- highly selective specificities
- improve during response
- memory
- more advanced
- resolves infection usually
Similar -common effector mechanisms for destruction of pathogens
Besides infectious processes, what is the immune system involved in?
- transplantation immunity
- autoimmune disorders
- hypersensitivity (allergies)
- tumors?
What is the immune system composed of?
cells:
- lymphocytes
- granulocytes
- macrophages, monocytes, dendritic cells
Molecules:
- antibodies
- cytokines
- complement
What are the lymphoid cells? where are they produced? Function?
B lymphocytes:
- made in bone marrow
- key in adaptive immunity (humoral)
T lymphocytes:
- 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
- heterodimer chain
- light chain with binding site
- heavy chain which anchors molecule, goes through transmembrane region
- more diverse
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?
CD4+:
- helper/inducer
- make cytokines
- regulate afferent (generation) and efferent (effecting the response) arms of many different types of response
- produce antibodies
- generate cell mediated and humoral responses
- Regulatory T cells
CD8+:
- 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
- activate macrophages
- inflammation
- 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?
Active:
- generate a response
- natural via infection
- artificial via vaccination
- specific
- has memory
Passive
- natural by transplacental or colostral transfer of antibody
- artificial by administration of immune globulins
- specific
- no memory
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?
- neutrophil (40-75%)
- lymphocyte (20-50%)
What are the cardinal features of adaptive immune response?
- specifity
- diversity
- adaptibility
- memory
- self limitation
- 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?
see pic
