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Chapter 2 Cells and Tissues of the Immune System
Challenge:
1. Respond to small numbers of many different microbes at any site. 2. Very few naive lymphocytes specifically recognize and respond to any one antigen. 3. The effector mechanisms of the immune system (antibodies and effector T cells) may have to locate and destroy microbes at sites that are distant from the site of initial infection.
CD4+ (Helper T lymphocytes)
Stimuli for B cell growth and differentiation (humoral immunity) Macrophage activation by secreted cytokines (cell-mediated immunity)
Cells of the Immune System
Normal Blood Cell Counts
Mean number per microliter White blood cells Neutrophils Eosinophils Basophils 7,400 4,400 200 40 Normal range 4,500-11,000 1,800-7,700 0-450 0-200 1,000-4,800 200-800