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.
The initial exposure to an antigen (allergen) that causes an allergic response is called sensitization.
The answer is sentizitation
Production of sufficient immunologic memory typically takes a few weeks following the initial antigen exposure.
exposure to 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
Yes, it is possible. It depends of course of the individual's sensitivity to that particular antigen.
B cells respond to the initial antigen challenge by producing progeny cells. The progeny cells include both memory cells and plasma cells.
During the first exposure to an antigen antibodies are produced
The class of immunoglobulin to respond to the fist exposure of an antigen is immunoglobulin class M (IgM). While Immunoglobulin G (IgG) would predominate on the second exposure.
IgM is produced upon initial exposure to an antigen. For example, when a person receives the first tetanus vaccination, antitetanus antibodies of the IgM class are produced 10 to 14 days later. IgM is abundant in the blood.