intro Flashcards
what is one of the major functions of the immune system?
protect the host from foreign microbial invaders that can occur across the whole body
list the microbial invaders
viruses
bacteria
parasites
fungi
how does the immune system recognize these microbes as foreign?
It looks for unique structures -antigens- at the macromolecular level (i.e. proteins, polysaccharide, lipids or nucleic acids) on the surface of or excreted by these microbes that it sees as foreign
what are epitopes?
foreign antigenic structures
what is another major function of the immune system besides protecting host against microbial invaders?
maintaining healthy microenvironment at the cellular level for all tissues and organs
in order for the immune system to serve as scavengers to remove cellular debris during injury and minimize inflammatory response, what must it do?
immune system must be able to identify these cells as “self” or “non-self”
what is the condition where the immune system is triggered to overreact to self-antigen leading to damage of tissues or the
development of lesions?
autoimmune disease
how would we classify the immune system if it is impaired at birth that is genetically linked and permanent?
congenital/primary immunodeficieny
what would the immune system be classified as if impairment occurs later in life?
acquired/secondary immunodeficiency
what are the two possibilities if a host is exposed to an aggressive virulent infection agent that the body has never seen before?
- The individual gets sick and dies.
- The individual gets sick and recovers
if an individual has recovered from a virus it has never encountered before, what does it mean that he has developed a resistance to that virus?
if he is re-exposed to that same virus again, he should not get sick or at most be slightly sick
what is the dogma of immunity?
Antigen exposure drives the immune response
true or false: not all animals (vertebrates and invertebrates) have an innate immune system
false
what are the two type of immune systems that vertebrates have?
innate and adaptive
what is the first line of defense for the host against foreign invaders and exists at birth?
innate/natural immunity
what are the major characteristics of innate immunity?
-rapid (minutes-hours)
- relatively non-specific in its response to foreign invaders
- lower potency
- lacks the generation of a memory response
what are the barriers of the innate immunity and provide examples
- physical (skin epithelium)
- cellular (neutrophils, dendritic cells, macrophages, complement, and NK cells)
- biochemical mechanisms (complement)
what is the immunity that can recognize and react to a huge number of foreign antigens (pathologic and nonpathologic)?
adaptive/acquired immunity
what are the major characteristics of adaptive immunity?
- specificity
- adaptability to changing antigen structure
- immunologic memory (anamnestic response)
what is a downside to adaptive immunity compared to innate?
it’s slower
what are the major components of adaptive immune response?
- cell mediated (T cells)
- humoral/antibody-mediated immunity (B cells)
when does active immunity occur?
after the host has been exposed to antigen via a natural exposure or via an artificial exposure (i.e. vaccination)
true or false: there is a time lag post post-exposure before immunity to arise
true
when does passive immunity occur?
when the host externally receives antibodies against a specific microbe or product generated by another individual.
what is the advantage of passive immunity over active?
passive is immediate upon transfer
what is the disadvantage of passive immunity over active?
no immunologic memory generated, Once the antibodies are used or degraded the immunity
ceases
what are classic examples of passive immunity?
maternal immunity that occurs in utero in
humans, in ovo in birds or postnatally via the suckling of colostrum in the veterinary species
what is adoptive transfer/immunization?
involves the transfer of immune cells into the host
where did the cells from adoptive transfer originate?
originated from the host and were manipulated in vitro outside of the host prior to a transfer back into the host.
What is the difference between a pathogenic and non-pathogenic antigen?
non-pathogenic antigen: organisms that do not cause disease, harm or death to another organism. The term is usually used to describe bacteria
pathogenic: agent that causes disease to the host
What are 4 examples of foreign antigens?
viruses, bacteria, parasites and fungi
What are the major cell types associated with the innate immune system?
NK cells
complement cells
neutrophils
macrophages
dendritic cells
What are the major cell types associated with the adaptive immune system?
T and B cells
