Listeria

Question 0

What are the clinical presentations of listeria?

Answer 0

gastroenteritis, meningistis, encephalities, maternal fetal transmission/ abortion, sepsis, death (20-30%)

Question 1

What are the special growth features of listeria?

Answer 1

can grow at low pH and low oxygen tension, can grow at low temps (proliferate in refrig), bile salts promote growth

Question 2

How does listeria gain access to cells?

Answer 2

1. ) Has proteins on surface that binds to cadherins and tyrosine kinases on apical side of intestinal epi cells and trigger phagocytosis of listeria by triggering a dormant actin polymerization pathway on cell surface
   2) Escapes phagocytic vessicle before it merges with a lysosome by expressing proteins listeriolynsinO that aggregate at membrane and insert pores (equilibrate pH, prevent binding) and by expressing phospholipases that weaken membrane by cleaving head groups off phospholipids
   3) Coopts actin polymerization machinery to move between cells (avoid immune response by not going outside of cells); express ActA on surface which is similar to Wasp that recruits ARP 2/3, capping protein, and cofillin

Question 3

Why is listeria a good target as an anti-cancer agent?

Answer 3

Precursors to cancer cells live in cancer niches that are acidic with low oxygen tension, and a mechanical barrier that lysteria has mechanisms to gain access to