4 - Lymphocyte Recirculation and Homing

Question 1

In What zone is the somatic hypermutation occur?

Answer 1

Germinal center of the follicle in the lymph node

Question 2

How do the naive lymphocytes (no contact with Ag yet) enter to the lymph nodes from the blood? How is molecularly mediated?

Answer 2

Through High endothelial venules (HEV)

L-selectin (naive lymphocytes) binds to addressins (HEV)

Question 3

Which condition can increase susceptibility of severe infection by babesia microti? Why?

Answer 3

Splenectomy
It’s an intraerythrocityc parasite (vector transmitted: same tick as Lyme disease) ▶️ infected RBC must be filtered in spleen.

Question 4

What findings do you expect to see in blood on a postsplenectomy individual?

Answer 4

Howell-jolly bodies (nuclear remnants)
Target cells
Thrombocytosis - lymphocytosis ▶️ loss of sequestration and removal (platelet)