Question

1. Which part of the AB toxin is required to bind to host cell surface?
   1. The A domain.
   2. The B domain.
   3. Both the A and B domains.
   4. AB toxin does not bind to host cell.
2. Which life cycle of Chlamydophila pneumonia is infectious?
   1. The inclusion bodies.
   2. The elementary bodies.
   3. The reticulate bodies.
   4. Both a and b.
3. Which cells are part of the granuloma:
   1. Dead macrophages.
   2. Active macrophages.
   3. CD4 T cells.
   4. All of the above.
4. Which E. coli strain is associated with the Type III secretion system:
   1. Enterotoxic E. coli (ETEC).
   2. Enteroinvasive E. coli (EIEC).
   3. Enteropathogenic E. coli (EPEC).
   4. All of the above.
5. The B. anthracis virulence factor consist of:
   1. PA = protective antigen
   2. EF = edema factor
   3. LF = lethal factor
   4. All of the above.
6. During Mycobacterium tuberculosis infection, list two immune cells that are important in controlling the infection and describe their roles.

Answer 1

• The B domain of the AB toxin is required to bind to the host cell surface.

B domain of AB toxin specifically interacts with a cell-surface receptor and facilitates internalization of the toxin into cellular transport vesicles, such as endosomes.

• The elementary bodies in the life cycle of Chlamydophila pneumonia are infectious.

In the life cycle of Chlamydophila pneumonia, elementary bodies attach to the surface of an epithelial cell that promotes pseudopod formation to engulf elementary bodies.