Type 4 hypersensitivity

Question 1

Type 4 hypersensitivity pathologic immune mechanism

Answer 1

activation of CD4+ and CD8+ t cells

Question 2

Type 4 hypersensitivity mechanism of tissue injury

Answer 2

macrophage activation and CTY lysis of cells

Question 3

type 4 hypersensitivity

Answer 3

delayed-type reaction - cell-mediated immune response initiated by T-cells

Question 4

induration

Answer 4

cutaneous or subcutaneous hardening that is caused by the cellular infiltrate - key manifestation of type 4 hypersensitivity

Question 5

sensitization stage (type 4)

Answer 5

subcutaneous antigen is processed by APC (langerhans cells) -> Th cell recognized HLA peptide on APC and differentiates into Th1

Question 6

Elicitation stage

Answer 6

subsequent antigen > Th1 activates > cytokines released > macrophage activation > accumulation of macrophages > tissue damage

Question 7

skin test for cell-mediated immunity

Answer 7

test measures the ability of CD4 Th1 cells to conduct DTH reactions