Antigens are molecules responsible for stimulating an immune response. Each antigen has unique surface features or epitopes, resulting in specific responses.
On the other hand antibodies (immunoglobins) are Y-shaped proteins produced by B cells of the immune system in response to exposure to antigens. Each antibody contains a paratope which recognizes a specific epitope on an antigen, acting like a lock and key binding mechanism. This binding helps to eliminate antigens from the body, either by direct neutralization or by using other parts of the immune system.
Therefore antigens and antibodies are opposite or enermies of each other.