Immuno Flashcards
Differentiate positive vs. negative selection of T cells and where does each process occur?
- Positive: T cells expressing a TCR able to bind self MHC are allowed to survive; occurs in thymic cortex
- Negative: T cells possessing TCRs that bind with high affinity to self antigen or self MHC class I or II are eliminated by apoptosis; occurs in thymic medulla
Septic arthritis in a young, sexually active adult should raise for suspicion for what organism?
Disseminated N. gonorrhea infection
Which important cause of UTI’s does not cause hemolysis (gamma-hemolytic) when grown on blood agar?
Enterococcus - Gram-positive cocci in pairs and chains
Leukocyte adhesion deficiency (LAD) type 1 results from the absence of what; leading to the inability to synthesize what?
Absence of CD18 —> inability to synthesize the beta-2 integrins Mac-1 and LFA1, affecting tight adhesion, crawling, and transmigration
How does HBV assist with the life cycle of HDV?
HBsAg must coat the HDAg of HDV before it can infect hepatocytes and multiply
Hyper IgM syndrome is most often due to a deficiency in what; how is it inherited?
CD40L deficiency; X-linked recessive
Which antibodies are specific for limited scleroderma (CREST) and diffuse scleroderma?
- CREST syndrome = anti-centromere antibodies
- Diffuse scleroderma = anti-DNA topoisomerase I (Scl-70) antibodies
What is the difference between Janway lesions and Osler nodes associated with Infective Endocarditis?
- Janeway: are nontender, macular, and erythematous lesions on the palms and sole; result of septic embolization from valvular vegetations
- Osler nodes: are tender, violaceous nodules located on the pulp of fingers and toes; due to immune-complex deposition in the skin