PARASITOLOGY CH 4

Adaptive immunity

Provides specific defense and immunological memory

Innate immunity

Immediate, nonspecific first line of defense

Schistosoma mansoni

Inhibits complement protein C9

Trichinella spiralis

Inhibits complement protein C1q

Entamoeba histolytica

Degrades C3a, C5b, and antibodies

Plasmodium falciparum

Converts hemoglobin into hemozoin

Hemozoin

Inhibits PKC activation and prevents superoxide formation

Leishmania lipophosphoglycan (LPG)

Delays phagolysosome formation and prevents NADPH oxidase assembly

Superoxide dismutase (SOD)

Breaks down superoxide radicals

Arginase

Competes with nitric oxide synthase and reduces nitric oxide production

Trichomonas vaginalis

Uses molecular mimicry to avoid immune recognition

Polyclonal activation

Floods serum with mostly non-specific antibodies

Extracellular vesicles

Modify host cell behavior to promote parasite survival

Wigglesworthia

Symbiotic bacterium essential for tsetse fly development and immunity

Braconid virus

Produces immunosuppressive proteins in wasps

Social immunization

Healthy ants expose themselves to low levels of pathogens to stimulate immunity

RNAi pathway

Destroys viral RNA

Toll pathway

Activated by Gram-positive bacteria, malaria parasites, and viruses

IMD pathway

Activated by Gram-negative bacteria, fungi, and Plasmodium falciparum

JAK/STAT pathway

Activated by viruses and some Plasmodium infections

Cas9

Endonuclease that cuts DNA

sgRNA

Guides Cas9 to the target DNA sequence

CRISPR-Cas9

Main components are sgRNA and Cas9

IL-4 and IL-13

Stimulate the weep and sweep response

Weep and sweep response

Includes mucus secretion and smooth muscle contraction to expel helminths

Trogocytosis

Neutrophils kill parasites by taking repeated small bites

Antibodies in trogocytosis

Act as opsonins to make parasites more visible to neutrophils

Drosophila larvae

Consume ethanol-containing food to combat wasp infections

Tsetse fly

Requires Wigglesworthia for proper development and immunity

Molecular mimicry

Parasites resemble host molecules to avoid immune attack

Complement system

Part of innate immunity that can be inhibited by parasites

Hemozoin

Produced by Plasmodium from hemoglobin degradation

Nitric oxide synthase (iNOS)

Competes with arginase for arginine

Leishmania

Survives in macrophages using LPG, SOD, and arginase

Memory

Characteristic feature of adaptive immunity