The document summarizes key aspects of the immune system, including: - The immune system has both an innate system that generally recognizes pathogens and an adaptive system that recognizes pathogens specifically. - The major cells of innate immunity are antigen presenting cells that break down proteins into peptides, load them onto MHC receptors, and transport them to the cell surface to be recognized by T cells to trigger an adaptive response. - The adaptive immune response involves both cellular immunity mediated by T cells against infected cells/pathogens and humoral immunity mediated by B cells and antibodies against bacterial infections and extracellular phases of viruses.

1. IMMUNITY SYSTEM
Immunochemistry

2. • All organisms are continually subject to attack by other
organisms
• In order to deal with them, animals have evolved an
elaborate protective array known as the immune system:
A. Innate immune system, which recognizes
pathogens according to their general
characteristics.
B. Adaptive immune system, which recognizes
pathogens according to their specific
macromolecules
INTRODUCTION

3. In response to pathogens, vertebrate immune systems
use two interconnected systems:
• Innate immunity
• Adaptive immunity
Innate vs adaptive immunity

4. The major cells of innate immunity
Big eaters/Always hungry
Antigen Presenting Cells (APCs)
Proteins eaten by APCs are broken down to small pieces (peptides),
which are loaded on special receptors (MHCs) and transported to the
cell surface. Peptide+MHC complex can be recognized by a T cell and that
interaction can lead to an adaptive immune response.

5. Adaptive immune response

6. A. Innate immune system

7. B. The Adaptive Immune Response
1. Cellular immunity, which guards against virally infected
cells, fungi, parasites, and foreign tissue, is mediated by
T lymphocytes or T cells, so called because their
development occurs in the thymus.
2. Humoral immunity (humor is an archaic term for fluid),
which is most effective against bacterial infections and
the extracellular phases of viral infections, is mediated
by immunoglobulins, produced by B lymphocytes or
B cells in the bone marrow.

54. d) In B cells, IgD's function is to signal the B cells to be activated
e) Recently, IgD was found to bind to basophils and mast cells and activate these
cells to produce antimicrobial factors to participate in respiratory immune defense
in humans.
f) IgD exhibits much structural diversity throughout vertebrate evolution, due to
alternative splicing & CSR (iClass Switch Recombination )
g) IgD induces basophil production of immunoactivating cytokines such as :
IL-4, IL-13 and BAFF, proinflammatory cytokines such as TNF and IL-1b,
and chemokines such as IL-8 and CXC chemokine ligand10 (CXCL10)

87. The immune system loses tolerance to some of its self-antigens,
resulting in an autoimmune disease:
• Myasthenia Gravis
• Systemic Lupus Erythematosus
• Rheumatoid Arthritis
• Insulin-dependent Diabetes Mellitus
• Multiple Sclerosis
• Crohn’s disease and Ulcerative Colitis
• Addison’s disease
• Hashimoto’s Thyroiditis
• Polyarteritis nodosa
• Dermatomyositis
• Celiac disease – sprue
• Graves disease
• Sjogren syndrome
• Pernicious anemia