Can a person can go into anaphylactic shock on their first exposure to an antigen?
Yes, it is possible. It depends of course of the individual's sensitivity to that particular antigen.
Does the first exposure to a pathogen result in a much faster immune response than the second exposure to the same pathogen?
Why does an RH-negative person have a transfusion reaction on the second exposure and not the first exposure?
Primary versus Secondary Immune Response The primary immune response occurs the first time that the immune system comes in contact with the antigen. During this time the immune system has to learn to recognize antigen and how to make antibody against it and eventually gain immunological memory. This primary response takes time (about two weeks) and during this time the person experiences signs of illness. IgM antibodies are the hallmark of a new infection because…
Why is it that an Rh-negative person does not have a transfusion reaction on the first exposure to Rh-positive blood but does have a reaction on the second exposure?
Because antibodies that cause the reaction are not naturally occurring. One has to be exposed to Rh in order to make antibodies to it. Its the same process as the reaction to a vaccine. The vaccine exposes you to an antigen and your body learns how to react to it in order to protect you from it. If you are exposed to the Rh factor, your body learns how to react to it, and so…
The surface immunoglotulin that serves as the B-Cell antigen receptor (BCR) has two roles in B-cell activation. First, like the antigen receptor on T cells, it transmits signals directly to the cell's interior when it binds antigen. Second, the B-Cell antigen receptor delivers the antigen to intracellular sites where it is degraded and returned to the B-cell surface as peptides bound to MHC class II molecules.
You could be allergy tested by a physician, which would likely include testing for bee or wasp venom. Otherwise, until you are stung you won't know whether or not you are allergic. The good news is, allergies tend to worsen with repeated exposure, so the first sting is not likely to cause anaphylactic shock.