lecture 3 Flashcards
innate immunity
a mechanism of defense that does not depend on prior exposure to the invader
adaptive immunity
specific to non-self material, requires time for development, and occurs more quickly and vigorously on second exposure
what immune cells are a part of adaptive immunity?
B cells and T cells (CD4+ T cells and CD8+ T cells)
what are cytokines and cytokine receptors:
protein hormones that play important roles in both the innate and adaptive immune system. They play a major role by which immune cells communicate
what are antimicrobial molecules?
important at surfaces where an organism meets the environment, i.e., skin or mucous membranes. they do not have high specificity and there is no prior immunizing experience with the microbe
PAMPS (pathogen associated molecular patterns)
pieces of bacteria and viruses that stimulate Pattern Recognition Receptors (PRRs).
GPIs (glycophosphatidylinositols)
glycolipids that are a ubiquitous feature of eukaryotic cell membranes
phagocytosis
process of engulfment of an invading particle within the invagination of the phagocyte’s cell membrane. The invagination is pinched off, the particle is enclosed, and lysosomes add digestive enzymes into the vacuole to destroy the particle
cells capable of phagocytosis:
- monocytes
- kuppfer cells
- dendritic cells
- granulocytes (neutrophiles, eosinophils, basophils
antigen:
a specific foreign substance that stimulates the adaptive immune response
where are antibodies (immunoglobulins) presented?
on the surface of B cells or plasma cells
where are T-cell receptors displayed?
on the surface of T-cells
function of antibodies in host defense:
- opsonization
- neutralization
- activation of complement
- antibody-dependent, cell-mediated cytotoxicity
humoral immune response:
response that protects extracellular spaces in the body by producing antibodies (by B cells) which destroys extracellular microorganisms and prevent the spread of intracellular infections
Helper T cells include:
Th2 class of CD4 T cells as and a subset of Th1 cells that help in B-cell activation
what happens in cell-mediated immunity (CMI)?
the epitope of the antigen is also presented by macrophages, but the Th1 arm of the immune response is activated as the Th2 arm is suppressed. As in humoral immunity, CMI displays a secondary response due to large numbers of memory T-cells produced from the original activation
B cells = …
antibody mediated (humoral) immunity
T cells = …
cell-mediated immunity
innate immune response characteristics
- rapidly deployed
- encoded in genome - conserved from flies to humans
- broad recognition of microbial “patterns”
- no memory of past encounter with antigen
adaptive immune response characteristics
- slow response
- specific recognition of millions of different potential antigens
- requires gene rearrangement to generate antigen specific receptors
- long term memory of past antigen encounter
inflammation:
inflammation is a vital process in the mobilization of body defenses against an invading organism or other tissue damage, as well as in the repair of damage.
necrosis due to inflammation may appear as….
abscesses or ulcers
how are many of the parasitic infections diagnosed?
by finding the parasites themselves, or their products, e.g., in the host feces
what are the techniques for diagnosing parasitic infections?
- skin tests
- indirect immunofluorescent antibody (IFA) assay
- indirect hemagglutination (IHA) assay
- enzyme-linked immunosorbent assay (ELISA)
pathogenic affects of parasites may include…
- trauma
- nutrition robbing
- toxin production
- interactions of host/inflammatory responses
microbial deprivation hypothesis
alteration of the microbial exposure may affect the maturation of the immune system. diseases resulting from this alteration include: IBD, MD, and T1D
hygiene hypothesis:
early childhood exposure to infectious agents, including “friendly microbes”, parasites and other pathogens, boosts the natural development of the immune system to react appropriately to stimuli. reduced exposure to these infectious agents in childhood suppresses the natural development of the immune system and increases one’s susceptibility to allergic diseases
infection vs. allergic disease in developed countries:
high incidence of allergic disease, low infection with worms (helminths)
infection vs. allergic disease in developing countries:
low incidence of allergic disease, high infection with worms (helminths)
insufficient stimulation of the ___ arm, stimulating the cell defense of the immune system, leads to an ___ ___ arm, stimulating the antibody-mediated immunity of the immune systems, which in turn led to allergic disease
Th1
overactive Th2
Helminthic Therapy:
a type of immunotherapy for the treatment of autoimmune diseases and immune disorders by means of deliberate infestation with a helminth or with the egg of a helminth
current helminthic treatments include:
- necator americanus (hookworms)
- trichuris trichiura ova, human whipworm eggs
- trichuris suis ova (TSO), pig whipworm eggs
favorable characteristics of Trichuris suis:
- closely related to human whipworm Trichuris trichuria
- produces a self-limited colonization in humans
- has no known pathogenic potential
- remains confined to the intestine
- does not multiply in the host
- cannot be directly spread to close contacts
- eggs can be obtained from pigs grown in specific pathogen-free environment
what diseases/health conditions is current helminthic therapy research targeted to?
- Crohn’s disease
- ulcerative colitis
- IBD
- MS
- rheumatoid arthritis
- asthma
- eczema
- dermatitis
- hay fever
- food allergies
