First line of defense; phagocytic cells; requires no previous exposure

• Physical- skin, tract linings
• Mechanical- urine, vomit, coughing
• Biochemical- Low pH, low temperature

Adaptive immunity

Specific defenses; B and T lymphocytes; more than one exposure

White Blood Cells

• Neutrophils- phagocytes (small and fast)
• Eosinophils- parasites, slow or stop inflammation, dissolve clots
• Basophils- release histamine (inflammation) and heparin (prevent clots)
• Monocytes/macrophages- phagocytes (big and slow)
• Lymphocytes- B & T, killer cells

Bandemia/Left shifting

Bands= immature, non-functional neutrophils

Left shifting occurs when # of bands increases; sign of a bad infection

• Clonal diversity-Production of T and B cells with all possible receptors for antigens

• Clonal selection- Selection, proliferation, and differentiation of individual T and B cells with receptors for a specific antigen

• Humoral immunity (freely circulating)
• Make antibodies (plasma cells)
• Immunoglobulins
• Memory B cells

• Cellular immunity
• Directly attack antigens
• Cytotoxic T cells- destroy infected cells
• Helper T cells- attract macrophages and enhance immune response by stimulating other T and B cells
• Regulatory T cells- control immune response, can be suppressor cells
• Memory T cells

Functions of antibodies

• Direct effects: Neutrilization, agglutination, precipitation
• Indirect effects: Opsonization (mark for phagocytosis)

• IgA- Found in body secretions
• IgD- Antigen receptor on surface of B cells
• IgE- Mediator of common allergic responses
• IgG- Most common
• IgM- First antibody produced in primary response to antigen

• Not digested and processed to be presented to an immune cell
• Activate many T cells and cause an inflammatory reaction and possibly fatal shock
• Examples: toxic shock syndrome and food poisioning

• Natural

• Passive- use someone else's antibodies (temporary)

• Active- make our own antibodies (vaccination, previous exposure to disease)

• Type I- Allergy, anaphylaxis (IgE, mast cells, histamine)
• Type II- Host antibodies attack host tissue antigens
• Type III- Antibody-antigen complexes get trapped in tissues and cause damage (examples: Raynauds, Lupus)
• Type IV- T cell mediated (graft rejection, poison ivy)

Part of immune system is missing

Classifications

• B lymphocyte
• T lymphocyte
• Complement
• Phagocyte

Immune system deficiency resulting from disease

Example: AIDS destroys T cells