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

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

ANSWER DOWNLOAD EXAMIANS APP

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

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

ANSWER DOWNLOAD EXAMIANS APP

Antigen
CD antigens

are expressed on immune cells to mark them for separation
allow leukocytes to recognize antigen
are each expressed on only one cell type
function as receptors for cytokine and CAMs

ANSWER DOWNLOAD EXAMIANS APP