WEEK 2: COORDINATING THE IMMUNE RESPONSE

Question 1

State the 2 types of inflammation.

Answer 1

Innate immunity
Adaptive immunity

Question 2

Where are the adaptive immune responses initiated and where are the lymphocyte maintained?

Answer 2

Lymphoid organs

Question 3

State the primary and secondary lymphoid organs.

Answer 3

*Primary lymphoid organs: Bone marrow, Thymus
*Secondary lymphoid organs: Spleen, lymph node. MALT, GALT and BALT, peyer’s patch, Tonsils

Question 4

Describe the lymphocyte traffic and recirculation.

Answer 4

Lymphocytes migrate via the bloodstream to the secondary lymphoid organs or tissues.

Lymphocytes enter the periarteriolar lymphoid sheath (PALS) by way of the marginal zone (MZ) and leave through the splenic veins (SV) in the red pulp (RP).

Lymphocytes enter the lymph nodes via the high endothelial venules (HEVs), in the paracortical regions and if they are not activated there pass via the efferent lymphatics (EF) into the lymphatic system and via the thoracic duct (TD) into the left subclavian vein.
(LSV).

Lymphocytes pass into the mucosal tissues through the HEV and return via the
afferent lymphatics (AF) of the draining lymph nodes

Question 5

How is the site of infection linked to the lymph node or spleen (where adaptive immune responses generated)?

Answer 5

*Microbe infects an individual or a
protein antigen is injected into the
skin,

   *Specialized APCs, mainly dendritic 
   cells in the skin and other 
   epithelia, bind microbial antigens
 
   *APCs transport these antigens 
   from the portals of entry to the 
   draining lymph nodes.

  *During their migration to the 
  lymph nodes, dendritic cells 
  mature and become efficient APCs.

IN THE LYMPH NODES
- Induction of response
-Antigen recognition in lymphoid organs
-T-cell expansion and differentiation.

TRAFFIC OF EFFECTOR CELLS TO THE SITE OF INFECTION

In lymphoid tissues:
*Activation of naive T lymphocytes and initiation of adaptive immune response
*Delivery via blood of effector cells and antibodies to site of infection.
*Activation of effector T-cells in infected tissues.