Question

haptens & adjuvants(Immunology)

Answer 1

Haptens are small well defined chemical groups such as dinirrophenol which are not immunogenicity on their own but can be activated by preformed antibodies.
Adjuvant modifies the activities of other agents.

Answer 2

Haptens  are  small organicmolecule.They are antigenic but not immunogenic because they can't activate the T helper cell.failure of hapten to activate T helper cell due to inability to bind with MHC protein.Haptens are not protein only a protein can be presented by MHC protein.Haptens are univalent.They activate only tha B cell when it is bind with carrier protein