Production of sufficient immunologic memory typically takes a few weeks following the initial antigen exposure.
Some more context would be helpful. This question sounds like it may be asking about antigen exposure in the field of allergic disease, but it's hard to be sure. Hypersensitivity reactions (the immune system basis for allergies) are based on the principle that allergy follows initial sensitization to an antigen.
Phagocyte
Memory B cells and memory T cells carry the record of the first exposure to an antigen in the body. These cells are generated during the initial immune response and remain in the body to provide a faster and stronger immune response upon re-exposure to the same antigen.
Active Immunity
exposure to antigen
Memory cell. Memory cells are a type of immune cell that remember specific antigens upon initial exposure, allowing for a faster and more effective response upon subsequent exposure to the same antigen.
1-Response is antigen-dependent 2-There is a lag time between exposure and maximal response 3-Antigen-specific 4-Exposure results in immunologic memory
antibody
B cells respond to the initial antigen challenge by producing progeny cells. The progeny cells include both memory cells and plasma cells.
Yes, it is possible for a person to go into anaphylactic shock on their first exposure to an antigen if they have a severe and immediate allergic reaction. This is known as anaphylaxis and can be life-threatening.
During the first exposure to an antigen antibodies are produced