Immunology 101: The Basics

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Andrew Blauvelt, MD

Dr Blauvelt provides us with the 10 most important take-home messages from his immunology presentation at MauiDerm NP+PA Summer 2014….

  1. Key features of the innate immune system include: rapid response, non-specificity, phagocytosis, no memory.
  2. Key features of the  acquired immune system include: slow response, very specific, lymphocyte-mediated, memory.
  3. Keratinocytes are active participants in generating immune responses by secreting numerous cytokines upon activation.
  4. 4.Toll-like receptors are pattern recognition receptors on keratinocytes that recognize foreign antigenic material.
  5. Antimicrobial peptides are natural antibiotic molecules found in skin that are abundant in psoriasis skin and sparse in atopic dermatitis skin.
  6. 6.Epidermal Langerhans cells are antigen presenting cells that recognize/process skin antigens and migrate to lymph nodes, where they present antigen to T cells.
  7. 7.T cells require 3 signals to become fully activated: 1) recognition of antigen by the T cell receptor via MHC on the surface of antigen presenting cells; 2) binding of co-stimulatory molecules on T cells and antigen presenting cells to one another; and 3) secretion of soluble cytokines by the T cells.
  8. CD4+ T cells are T helper cells that recognize antigen via MHC class II and secrete cytokines to enhance CD8+ T cell and B cell immune responses, whereas CD8+ T cells are cytotoxic T cells that recognize antigen via MHC class I and kill cells upon contact.
  9. B cells secrete antibodies that specifically bind to antigen.
  10. Primary immune responses are slow, occur after first exposure to antigen, and involve creation of memory cells, whereas secondary immune responsesare fast, occur after subsequent exposures to antigens, and involve reactivation of memory cells.