Phagocytosis, Lymphocytes & Antibody Production

Define phagocytosis

Engulfment of solid pathogens by leukocytes

What are leukocytes?

White blood cells

What draws leukocytes to infection sites?

Chemokines via chemotaxis

Define amoeboid movement

Movement using pseudopodia through tissues

Describe macrophage destruction of pathogens

Engulf pathogen, form vesicle, fuse with lysosome (phagolysosome), digest with enzymes

How does phagocytosis link to adaptive immunity?

Antigens are presented on phagocyte surface

What are lymphocytes?

Specialized leukocytes of adaptive immunity

Where do B cells mature?

Bone marrow

Where do T cells mature?

Thymus

Define antigen

Foreign molecule triggering immune response

Define antibody

Y-shaped protein produced by B cells targeting specific antigens

What are antigens usually made of?

Proteins, peptides, polysaccharides or glycoproteins

Why are organ transplants difficult?

Different self-markers cause rejection

Define agglutination

Clumping of blood cells

Define hemolysis

Destruction of red blood cells

What is Rhesus factor?

Additional antigen (Rh positive or negative)

Why is O-negative universal donor?

No A, B or Rh antigens

Describe helper T cell activation

Macrophage presents antigen in lymph node, matches helper T cell receptor

What do activated helper T cells release?

Cytokines

What do cytokines do?

Activate B cells and other T cells

Define clonal selection

B cells divide to produce identical plasma cells

How many antibodies can a plasma cell secrete?

About 2,000 per second

State that B cells require helper T activation

B cells secrete antibodies only after activation by helper T cells