Antigen
The antibiotic penicillin is a small molecule that does not induce antibody formation. However, penicillin binds to serum proteins and forms a complex that in some people induces antibody formation resulting in an allergic reaction. Penicillin is therefore

both an antigen and a hapten
an antigen
a hapten
an immunogen

ANSWER DOWNLOAD EXAMIANS APP

Antigen
During the lag period between antigen contact and detection of adaptive immunity,

antigen is hidden from the immune system in macrophages
innate immunity blocks the activation of adaptive immune effector cells
new B and T cells with the appropriate antigen specificity must be produced in the bone marrow
innate immune effectors are eliminating antigen

ANSWER DOWNLOAD EXAMIANS APP