Intro to Immunology and the Immune System Flashcards
define immunity
state of protection from infectious disease
define vaccination
administration of an attenuated (altered/weakened) strain of a pathogen to provide immunity to a disease
describe herd immunity
the decrease of the number of individuals in a population that are susceptible to a disease that decreases the chances that a susceptible individual becomes infected; the fewer that can harbor a disease, the smaller the chances of it being passed on
what are immunoglobulins also called?
antibodies
where are immunoglobulins found?
in the body humors, or fluids
what is humoral immunity?
the branch of the immune system found in the body humors
what is passive immunity?
the transfer of immunity from one individual to another, or antibody transfer
how long does passive immunity last? why?
generally short-lived because there is no transfer of the cells that produce the antibodies, just transfer of the actual antibodies
what is active immunity
the production of one’s own immuntiy
how is active immunity accomplished? (2)
- vaccination
2. contracting the pathogen
how long does active immunity last? why?
it is long term because the cells that encountered the pathogen are still present and can continue to protect
what was the first immune cell discovered and in where?
lymphocytes; wer discovered the chicken
what are T cells and B cells named that way?
for where they were discovered in the chicken
T cells discovered in the Thymus
B cells discovered in the Bursa of Fabricious, in Bone marrow everywhere else
what is cell mediated immediated immunity?
branch of the immune system where cells eliminate the pathogen
what are the 2 branches of the immune system?
humoral and cell mediated immunity
what is an antigen?
any substance that elicits a specific response by B and T lymphocytes, or anything the body sees that shouldn’t be there
what are the 2 types of antigens?
- pathogenic
2. non-pathogenic
what do pathogenic antigens do?
cause disease
what do nonpathogenic antigens do?
don’t cause disease, can cause other things like allergies
what can all cell-surface proteins do?
serve as antigens if they’re not in their normal place
can one lymphocyte react to multiple antigens?
no; lymphocytes only express specific receptors for one specific antigen
what is clonal selection?
when the binding of an antigen by a lymphocyte results in proliferation of the lymphocyte to produce many exact copies
what comes after cloncal selection?
production of B cells that produce antibodies specific to the one antigen
what MUST happen in order for an immune response to occur?
the proper lymphocte must come into contact with the proper antigen
what are pathogens? give 4 examples
organisms that cause disease
- viruses
- bacteria
- fungi
- parasites
in what 3 ways does recognition of a pathogen occur?
- PAMPs and PRRs
- lymphocyte diversity
- tolerance
what are PAMPs?
pathogen-associated molecular proteins; common foreign structures that characterize a whole group of pathogens
give an example of a PAMP
gram negative lipopolysaccharide; not found in birds or mammals so recognized as other and bad
what are PRRs?
pattern recognition receptors
where are PRRs found?
found on immune cells
what do PRRs do?
recognize PAMPs and lead to an immune event cascade
describe lymphocyte diversity
population of B and T cells where each cell has many copies of receptors that are unique to one particular antigen
how is lymphocyte diversity determined? is it genetic?
determined before pathogen contact and is NOT genetic
describe tolerance in pathogen recognition
discrimination between self vs. nonself antigens; destruction of cells that are reactive to self-antigen
what are the 3 components of the innate immune system?
- physical and chemical barriers
- PRRs
- complement
what is the innate immune system?
the part of the immune system that animals are equipped with from birth
describe how the innate immune system functions (speed and specificity) and why
fast and nonspecific; does not recognize specific antigens, just commonalities amongst pathogens
give 2 examples of physical barriers in the innate immune system
skin, mucus MEMBRANES
give 2 examples of chemical barriers in the innate immune system
the mucus itself, secretions like HCl in stomach
is the innate immune system effective?
yep, can neutralize a lot of pathogens and often works to prevent the adaptive immune system from needing to activate
describe the adaptive immune system
learned immunity that is enhanced and adapts after encountering a specific antigen
describe how the adaptive immune system works (speed and specificity) and why
is HIGHLY specific and forms memory, but response is delayed 5-7 days because need to make the cells for it
in order to be effective, where should the immune system components be located? what need does this location then require?
spread throughout the body; need a way to communicate
what are the 2 forms of communication in the immune system?
- cell to cell contact
2. chemical messengers
when does cell to cell contact work as a method of communication in the immune system?
only if the cells are in close proximity to each other
what do the chemical messengers of the immune system allow?
communication across long distances
who are the 2 chemical messengers of the immune system?
- cytokines
2. chemokines
what are cytokines?
the hormones of the immune system, the chemical messengers
what are chemokines?
a type of cytokine that attracts other cells to the site of an infection
what is the basis of memory in adaptive immunity?
primary, secondary, and following exposures
describe the primary response of the immune system
what does it result in? how long does it take?
the first encounter with an antigenl results in clonal selection of effector cells and memory cells and takes 5-7 days
what are effector cells?
fight infection, produced in large quantities in the primary response
what are memory cells?
stick around for later exposure after the primary response, where they are produced in small numbers
describe the secondary response
what does it eliminate? how does the host feel?
subsequent encounter with the same pathogen; eliminates the 5-7 day delay due to already made memory cells; usually clears antigen without host feeling symptoms
how long do memory cells usually last?
very pathogen specific, broad range
what is the basis for vaccination?
use of memory cells; vaccine is primary reponse and real world exposure is the secondary response
