Haptens: Small organic molecule (e g. 1-Fluoro-2,4-dinitrobenzene)

Haptens: Small organic molecule (e.g. 1-Fluoro-2,4-dinitrobenzene)

• Haptens: Small organic molecule (e.g. 1-Fluoro-2,4-dinitrobenzene)

• Not Immunogenic by themselves

• Can be immunogenic when attached to an immunogenic macromolecular carrier

• The Anti-hapten antibody so generated will bind the Hapten

• Epitope: A region of a macromolecular antigen that is actually an antigenic determinant,

• a molecular sub-region that is actually recognized and bound by an Antibody or T-Cell Receptor

Cancer Antigens in Diagnosis of Cancer

• Cancer Antigens in Diagnosis of Cancer

• Carcino-Embryonic Antigen (CEA)

• Prostate Specific Antigen (PSA)

• Ovarian Cancer Antigen (CA 125)

• Breast Cancer Associated Antigens: BRCA1 and 2

• Whole-body Imaging of Metastatic Colon Carcinoma

• A33 Antigen

• Anti-Human Chorionic Gonadotropin Pregnancy Test (Early Home Pregnancy Test)

• Type II Allergic Hypersensitivity

• Blood Group Antigens in Transfusions (A, B, AB, O Blood Groups)

• Hemolytic Disease of New-Borns: Rh Antigen incompatibility

• Super-Antigens in Toxic Shock Syndrome

Cancer Antigens as Targets for Therapy

• Cancer Antigens as Targets for Therapy

• Antibodies as Anti-cancer Agents

• Radioactively-labeled Antibodies

• Cytolytic Antibodies

• Specifically-activated Cytotoxic T-Cells as Anti-Cancer Agents

• Specifically Activated Antigen-presenting Cells (Tc).

• Specifically Activated Helper T-Cells (TH)

Caused by Gram Negative Bacterial Endotoxins: (Endotoxins = Agent is in the Outer Membrane)

• Caused by Gram Negative Bacterial Endotoxins: (Endotoxins = Agent is in the Outer Membrane)

• Examples -

• E. coli

• Pseudomonas aeruginosa

• Neisseria meningitidis

• Meningococcus

• 70,000 Deaths per year

• Diarrhea, Fever, Blood Clotting, Blood Pressure Drop

• Macrophage Activation by Endotoxin:

• Generates systemic cytokine production -

• IL1 and TNF-alpha (Tumor necrosis factor)

Exotoxins = Secreted or Presented Membrane Bound:

• Exotoxins = Secreted or Presented Membrane Bound:

• Act as "Superantigens"

• Examples -

• Staphylococcus aureus:

• TSST1 (Toxic Shock Syndrome Toxin)

• Streptococcus pyrogenes - Rheumatic fever and shock

• Staphylococcus enterotoxins: Food poisoning

• Superantigens cross-link TCR with Antigen-presenting Cell MHC Class II Proteins

• Again Generates systemic cytokine production – IL1 and TNF-alpha (Tumor necrosis factor)