Lecture 49+50+DLA Flashcards
cell-mediated immunity to viral infection
intracellular
NK cells: These are cytotoxic for virus-infected cells and participate in antigen-dependent cell mediated cytotoxicity (ADCC)
Cytotoxic CD8+ T cells: Destroy cells with viral peptides presented on cell surface in association with class I MHC
humoral immunity to viruses
antibodies
interferons: alpha and beta (produced by virally infected cells; will inhibit transcription and translation in neighboring cells)
IFN-gamma = activates macrophages and NK cells
upregulate MHC I
how do viruses avoid immunity
antigenic shift and drift polymorphism latency modulation of MHC infection of the lymphocytes prevention of complement activation
cell mediated immunity for intracellular bacteria
cells infected can activate the NK cells
(cytotoxicity and activation of macrophages)
CD8 T cells will recognize MHC I and lyse
once lysed:
APC
Th1 cell
Bacteria antigen are processed and presented with
class II MHC molecules on the surface of APCs to
CD4+ T cells
humoral immunity for extracellular bacteria
the complement pathway
c3b = opsonin
c3a and c5a = recruit leukocytes
MAC: perforate the membrane of gram -
lysozyme: attack peptidoglycan
antibody: principle defense
how do bacteria avoid immunity
prevent phagocytosis (capsules)
killing phagocytes
neutralizing the ab’s
survival within the phagocyte
prevent complement activation
avoid recognition (polymorphism)
humoral immunity to protozoal infection
Complement and antibody are important during the
extracellular stage of infection.
Opsonizes the protozoa and cause lysis
cell-mediated immunity to protozoal infection
important during the intracellular phase
Phagocytosis: macrophages, monocytes and neutrophils
CD4+ T-cells are activated
Cytotoxic CD8+ T-cells: important in the intracellular
stage (e.g, sporozoite stage of Plasmodium falciparum,
which causes malaria)
NK cells
how protozoa avoid the immune system
escape into the cytoplasm following phagocytosis
prevention of the complement activation
antigen variation via gene switching
parasitic worms and immune response
process as an extracellular organism: antibodies (IgE) and complement are the most important attack mechanisms
Th2 cell-mediated production of IgE
immune response to fungi
innate immunity controls most fungal infection
phagocytosis by neutrophils
the alternative and lectin pathways
defective Th17
Defective Th17 cell differentiation has been linked to
recurrent filamentous fungi and the occurrence of
mucocutaneous candidiasis in patients with primary
immunodeficiencies
Physician Impairment
means a physical, mental, or substance-related disorder that interferes with a physician’s ability to undertake professional activities competently and safely
signs and symptoms of impairment
ataxic gait slurred speech tremor Disheveled Appearance weight change mood alcohol breath more absence from work more accidental injury
professional lapses
writing, requesting, and diverting narcotics, stimulants or sedatives for self-use
