Hapten

HAPTENS ARE LOW MOLECULAR WEIGHT COMPOUND, MOSTLY SMALL ORGANIC MOLECULES THAT ARE ANTIGENIC BUT NOT IMMUNOGENIC. THEY CAN BIND TO ANTIBODIES BY THEMSELVES BUT THEY ARE NOT RECOGNISED BY THE IMMUNE CELLS

1. PRESENTED BY SUMAN TALUKDAR M.Sc. 2 ND SEMESTER DEPARTMENT OF BIOTECHNOLOGY GAUHATI UNIVERSITY HAPTENS + = HAPTEN CARRIER CONJUGATE

2. To know hapten we must know the following terms Antigen - Any substance (as an immunogen or a hapten ) foreign to the body. Immunogen - An   immunogen  is any antigen that is capable of inducing humoral and/or cell-mediated immune response. Antigenicity - The ability to bind specifically to antibodies Immunogenicity - The capacity to induce immune response or production of antibodies. MOST IMPORTANTLY All immunogen are antigen but all antigen are not immunogen

3. WHAT IS HAPTEN ??

4. Hydralazine Urushiol Halothane Dinitrophenol Penicillin Fig- Structure of some haptens

5. WHY HAPTENS ARE NOT IMMUNOGEN ?

6. WHY HAPTENS ARE NOT IMMUNOGEN ? POSSIBLE REASONS WHY HAPTENS DO NOT BIND TO MHC-II PRR of immune cells cannot recognize haptens because absence of PAMP on haptens. Also haptens are mostly not protein. T herefore cannot be internalized by APCs. As a result MHC-II on surface of APCs do not carry hapten . Hence TCR on surface of T-cell cannot recognize hapten .

7. ALSO…. Does not meet the minimal requirements that are needed to be an immunogen PROPERTIES OF IMMUNOGEN SIZE >10,000 Da COMPLEXITY Polymers>Monomers FORM Aggregated>soluble Brock biology of microorganisms, Michael T. Madigan et. al. — Fourteenth edition.

8. BUT…

9. Antibodies are generated against hapten , carrier protein and hapten -carrier conjugate

10. Some examples of haptens Urushiol from the plant poison ivy Hydralazine (generates autoimmune disease, Lupus erythematosus ) Nickel ion (ACD-allergic contact dermatitis)  Halothane (cause hepatitis) Penicillin ( hemolytic anemia)

11. CONJUGATE VACCINE When hapten carrier conjugate is introduced in body antibodies are generated against hapten , carrier protein and conjugate. This principle is used to generate vaccine against haptens , which may cause autoimmune disease.

12. Reference Brock Biology of Microorganisms, 14th Edition Michael T. Madigan,‎ John M. Martinko ,‎ Kelly S. Bender ,‎ Daniel H. Buckley,‎ David A. Stahl,‎ Thomas Brock Kuby Immunology, 7th Edition 7th Edition, Judith A. Owen, ‎ Jenni Punt, ‎ Sharon A. Stranford .