Exam 4 Lecture 19: Fungal & Parasitic Infections Flashcards
Helminth parasite
Multicellular eukaryotes with distinct organelles, usually has multistage development
Protozoan parasite
Single celled eukaryotes, usually have multistage lifecycle and multiple hosts
Parasite and definitive host of schistomiasis
Parasite: freshwater flukes
Definitive host: snail
Parasite and definitive host of soil transmitted helminth disease
Parasites: roundworm, hookworm, whipwor
Definitive hosts: mammals
Parasite and definitive host of lymphatic filariasis
Parasite: parasitic worm
Definitive host: mosquitoes
What parasite causes sleeping sickness and how does it use variable surface
glycoproteins (VSG) to evade host immunity through gene conversion?
Single celled protozoan parasite called trypanosomes
encode thousands of variants of surface glycoproteins (VSG) results in cyclic parasitemia -> immune system must try to keep up with newest antigens
What animal is the definitive host for Toxoplasma gondii and how is it
controlled by the immune system?
Host: cats
Most people (strong immune systems) are asymptomatic, people with weakened immune systems (or pregnant) are at risk
What does it mean for a disease to be a “WHO Neglected Tropical Disease”?
Endemic infectious diseases that have biggest impact on poor populations that lead to substantial disease burdens
What are the major components of a Th1 response against protozoan parasites?
Inducing cytokine: IL-12
Master Tf: T-bet
Cytokine produced: IFN gamma
Protective function: intercellular bacteria, virus, parasites
What are the major components of a Th2 response against helminth worms?
Inducing cytokine: IL-4
Master Tf: Gata-3
Cytokine produced: IL-4, IL-5, IL-13
Protective function: extracellular (large) parasites
Antibodies: IgE
Effector cells: the eosinophil, basophil, mast cells
Distinct role of basophils
Initiate Th2 response
Short lived circulatory (Migrate to 2ndary lymphoid tissue)
Produce IL-4, IL-13 -> polarized other immune cells
Assists with B cell maturation through CD40L-CD40 binding
Distinct role of eosinophils
Short lived Tissue resident innate cells
Secrete toxic inflammatory mediators
Kept at low numbers in healthy people because they can cause damage
Th2 cytokines lead to increased eosinophil production in bone marrow
Distinct role of mast cells
Long lived tissue resident effector cells
Present in all vascularized tissue
Promotes tissue integrity and repair
Cytoplasm packed with up to 200 granules filled with inflammatory mediators
Retains sugar molecules form past infections or allergic reactions
Inflammatory mediators
Found in mast cells
Pre formed
Histamine: increases endothelium permeability, smooth muscle contractions, airway construction, mucus secretion
TNF: activated endothelial cells to increase adhesion molecules to increase leukocyte migration
Proteases: enzymes to break down extracellular matrix
Made then released
IL-4 & IL-13: amplify Th2 response
Lipid mediators
Lipid mediators
Found in mast cells
Aka eicosanoids
2 classes-
Leukotrienes: similar to histamines
Prostaglandins: dilates blood vessels, increases blood vessel permeability, attracts neutrophils
Aspirin blocks prostaglandin synthesis
