What are the differences between antigen and antibody?

Basis of differentiation

Antigen

Antibody

Definition

An antigen is any substance that triggers an immune response in the body

An antibody is a blood protein that is generated against a specific antigen

Classification

Can either be proteins, carbohydrates, nucleic acids, or lipids

Are glycoproteins 

Effect in body

Can cause either diseases or allergic reactions

Protects the body from antigens by lysing the pathogen or immobilizing the antigen

Types

The four types are exogenous antigens, autoantigens, neoantigens, and endogenous antigens

The five types include: IgM, IgG, IgE, IgA, and IgD

Antigen-antibody interaction

Acts as the key

Acts as the lock 

Domain interactions  

Interacting domain with the body is known as the epitope

The variable region of the antibody which specifically binds to the epitope is called the paratrope