Quiz Questions Exam 1 Flashcards
What is the One Health Initiative?
Human Health, animal health, and global health are inextricably linked
Most emerging infectious disease outbreaks occur for what reason?
Humans encroach on wilderness and wildlife, changing the balance of the ecosystem
What factors led to the increase in Lyme disease in the US?
Deforestation caused the loss of predators of the white-footed mouse, which is a very bad groomer, so overpopulation of infected mice led to higher rates of infected ticks and higher rates of transmission to humans
Which factors have led to decreases in the incidence of infectious diseases?
Vaccines, drug development, education
What is the primary difference between a Gram + and Gram - bacterial cell wall?
Gram+ has a thick peptidoglycan layer with teichoic acids and Gram- has a thin peptidoglycan layer with an outer membrane containing lipopolysaccharides
Why do some bacteria produce spores?
Spores allow the bacteria to survive in a dormant state under environmentally harsh conditions.
What are the characteristics that define a Virus?
- Obligate intracellular parasite
- chromosome can be RNA, DNA, segmented, and packaged inside either a naked capsid or a capsid with an envelope
envelope or naked capsid:
- environmentally labile
naked
envelope or naked capsid:
- spread easily by fomites
naked
envelope or naked capsid:
- released by budding
enveloped
envelope or naked capsid:
- detergents destroy infectivity
enveloped
envelope or naked capsid:
- still infectious if it dries out
naked
envelope or naked capsid:
- requires antibodies and cell-mediated immune response
enveloped
envelope or naked capsid:
- survives the gut to cause foodborne illness
naked
envelope or naked capsid:
- coated with lipids and glycoproteins
enveloped
Bacterial and viruses make errors during replication, resulting in mutations in genomes.
- Bacteria have multiple mechanisms for genetic repair, including recombination, SOS response, and excision
- Homologous recombination is used by both bacteria and viruses to repair genetic mutations, and also gain functions such as antibiotic/antiviral resistance
- Mutation and repair mechanisms can be used to engineer bacteria and viruses for use in medical applications and as tools for research
There are 7 steps all viruses must go through to effectively replicate. What is not a step in the replication cycle of a naked capsid virus?
- budding
A lipopolysaccharide is:
- only gram - bacteria
- also called the O antigen
- made up of repeating polysaccharide units
- an endotoxin
the first defensse against pathogens is
- physical and chemical barriers
function of eosinophils
granular cells that defend against parasites by releasing peroxidase and phosphatases, and also involved in allergic response
function of basophils or mast cells
granular cells that release histamine during an inflammatory or allergic response
function of neutrophils
primary phagocytic defense against bacteria; these cells ingest and degrade the bacteria but do not present antigen to activate the adaptive response
function of monocytes
circulating cells that differentiate into macrophages or dendritic cells in tissues
function of dendritic cells
professional antigen presenting cells that phagocytose pathogens, migrate to the draining lymph node, and present antigen to naive T cells to initiate the adaptive response
function of macrophages
antigen presenting cells that phagocytose pathogens, presenting antigens to T cells, and produce cytokines/chemokines to enhance the inflammatory response
function of NK cells
granular lymphocytes that kill infected or tumor cells without requiring activation through a T cell receptor and MHC
function of CD4 T cells
help initiate and direct adaptive immune response
function of CD8 T cell
recognize and kill infected cells after activation by T helper cells
function of plasma B cells
produces antibodies
function of memory cells
remember a previous threat to response to a second exposure very rapidly
during the innate response, what occurs?
Neutrophils phagocytose bacteria to clear the infection, macrophages phagocytose bacteria and produce cytokines/chemokines to recruit additional monocytes and neutrophils to the site, and dendritic cells phagocytose bacteria and migrate to the draining lymph node and present antigen to naive T cells to initiate the adaptive response
What are the 3 main functions of macrophages?
- phagocytosis
- antigen presentation
- cytokine secretion
where do dendritic cells presnt antigen to naive T cells?
paracortex of the lymph node or the white pulp of the spleen
receptors on phagocytic cells recognize specific types of molecules on/in bacteria and viruses. these molecules are referred to as:
Pathogen Associated Molecular Patterns (PAMPs)
What do TLRs recognize?
bacterial and viral DNA, ssRNA, dsRNA, flagellin, and various other molecules specifically associated with pathogens
what are some of the factors in body secretions (tears, saliva, mucus) that have antimicrobial activity?
defensins, lactoferrin, immunoglobulin A
Most cells in the body express ____ molecules containing “self” antigen unless they are infected or cancerous; if the express “non-self” bits, NK and CD8 cells will recognize and kill them. Antigen presenting cells phagocytose pathogens and express bits of the pathogen in ____ molecules to present antigen to T and B cells.
- MHC class I
- MHC class II
What is the result of the acute phase response?
fever, metabolic changes, and activation of the complement system
the lymph nodes and spleen have similar purposes, but the spleen has an additional purpose. What functions do the have in common and what additional function does the spleen have?
both filter antigens from host fluids, facilitate antigen presentation to naive T cells and B cell activation, and the formation of germinal centers, but the spleen also filters old blood cells from the blood and recycles them
branch of the immune response:
- targets extracellular pathogens
humoral
branch of the immune response:
- targets intracellular pathogens
cell-mediated
branch of the immune response:
- targets all types of pathogens the same way
innate
branch of the immune response:
- characterized by inflammation, acute phase response, complement, and interferons
innate
branch of the immune response:
- characterized by B cell production of antibody
humoral
branch of the immune response:
- characterized by CD8 T cell, NK T cell and macrophage-induced killing
cell-mediated
the process through which B cells improve their affinity for their cognate antigen is called ___
somatic hypermutation
the process through which B cells change the base portion (Fc portion) of their antibody (to IgA, IgE, or IgG) after encountering an antigen is called ___
class switching
A particular B cell that is activated independently of Th cells would secrete what type of antibody in response to an infection.
IgM
What are 3 mechanisms used by CTLs to kill their target cells?
- directly killing the target cell by releasing granzyme B and perforin
- Inducing apoptosis in the target by releasing TNF-alpha and IFN-gamma
- inducing apoptosis by Fas-FasL interactions with the target cell
antibody component/function
- binds antigen
variable region
antibody component/function
- binds to receptors on cells to faciliate phagocytosis
Fc region
antibody component/function
- goes through somatic hypermutation
variable region
antibody component/function - goes through class switch recombination
Fc region
Th1 / Th2
- CTLs
Th1
Th1 / Th2
- macrophages
Th1
Th1 / Th2
- IL4
Th2
Th1 / Th2
- IL5
Th2
Th1 / Th2
- Extracellular pathogens
Th2
Th1 / Th2
- intracellular pathogens
Th1
Th1 / Th2
- IFN-gamma
Th1
Th1 / Th2
- allergies
Th2
Th1 / Th2
- antibodies
Th2
