Lecture 5 - Immune System

Question 1

Innate Immunity

Answer 1

• not specific to type of challenge
  Includes:
  -epithelial barriers (skin, mucous membrane)
  -phagocytic leukocyte (neutrophils, monocytes/macrophages)
  -Natural Killer (NK) cells
  -Proteins of the compliment system

Question 2

Adaptive Immunity

Answer 2

-specific = tailors its response to specific antigens
-activates when processes overcome innate immunity
2 types:
1. Humoral immunity - antibody production by B lymphocytes
2. Cell-mediated / Cellular immunity - T lymphocyte mediated

Question 3

T cells

Answer 3

• adaptive immunity; mediate cellular immunity
• differentiate in thymus; stored at interfolicular zones of lymph nodes
• comes to cell, recognizes it as foreign cells, phagocytize cell, presents its antigen to B cells
• releases cytokines to regulate immune response
• T-helper cells turn on B cells to produce antigens

Question 4

B cells

Answer 4

• adaptive immunity; humoral immunity
• bone marrow derived; stored at germinal centers of lymph nodes
• proliferation/differentiation from B cells to plasma cells to make antibodies
• Antibodies produce in different classes with specificity and progressive affinity for the antigen as production continues.

Question 5

Systemic anaphylaxis

Answer 5

• Type 1 hypersensitivity = most common, IgE production sensitive mast cells = allergic response
• parenteral exposure to antigens (ex. bee sting, drugs)
• results in systemic vasodilation and shock if not taken care of
• Atopy - allergy possibly heritable

Question 6

Graves disease

Answer 6

• Type 2 hypersensitivity = antibodies target self (inappropriate response)
• antibody produced binds to TSH receptor that trigger production of thyroid hormone
• results in hyperthroidism (overproduction of thyroid hormone = increased metabolism

Question 7

Systemic Lupus Erthematosus

Answer 7

-Type 3 hypersensitivity = antibody +antigen complex gets stuck to blood vessel
-antinuclear antibodies = directed against nucleus of cell
-variable clinical presentation; many possible tissue targets
-seen in females more than males
Ex. acute vasculitis causes problems in multiple regions

Question 8

Type 1 Diabetes melitus

Answer 8

• type 4 hypersensitivity = delayed hypersensitivty or direct cell cytotoxicity of T cells
• antigen: pancreatic islet beta cells
• results in diabetes from lack of insulin production

Question 9

X-linked agammaglobuniemia (Burton Disease)

Answer 9

• agammaglobuniemia= “without antibodies”
• primary deficiency (genetic immune deficiency disease)
• pre-B cells can’t differentiate into B cells, thus no plasma cells, thus no antibodies
• signs at 6 months old, “bubble boy”
• suffer recurrent bacterial infections

Question 10

DiGeorge Syndrome (Thymic Hypoplasia)

Answer 10

• Primary deficiency = congenital (heritable)
• defect in thymic development. Hypoplasia (small/not present).
• T cells differentiate in thymus, so T cells are absent.
• Susceptible to viral, fungal, protozoan, intracellular bacterial infections
• defect in fourth pharyngeal pouches
• associated with chromosomal deletion

Question 11

Kaposi’s sarcoma

Answer 11

• most common neoplasm - seen in AIDs patients (secondary immune deficiency)
• vascular; lesions typically seen in older man but much more aggressive in those w. secondary immune deficiency
• seen on skin, mucous membrane, lymph nodes, and lungs
• associated with KS herpes virys (KSHV)