Answer:
1-Clonal selection is the specific replication of some point lymphocytes that have the antibodies and receptors for a certain antigen, this is what is sought in response to measles disease, since the inoculation of the vaccine causes the first infection to of with the inactive injection of the virus without generating disease (active acquired immunity, since we do not inoculate the synthetic antibody, but it is manufactured by the body). Thus, the second infection caused by the measles virus in the 6-year-old child does not become ill because it replicates to those lymphocytes that have the specific antibody for this virus thanks to the vaccine (clonal selection).
Step-by-step explanation:
Regarding immunological tolerance and hypersensitivity reactions, it can be said that they are opposite situations in the world of immunology.
The immune tolerance is the null reaction of the defense before an antigen but not the absence of the defense, that is to say that it remains activated in a balanced way without decreasing or increasing when presenting a certain antigen, a clinical case before this is people who are people tolerances to lactose or bee pollen, these two chemical compounds would be the antigens tolerated without genera react to consumption or inhale.
On the other hand, on the other hand we have hypersensitivity reactions that are an increase in the immune response and sometimes it is even excessive, causing the death of the patient through anaphylactic shock.
Hypersensitivity is classified into 1 2 3 and 4, thus drafting different immunological situations such as hypersensitivity to antigens, organs, transplants, and even components of the body.
A very traditional case of hypersensitivity is people who can eat strawberries or nutmeg to trigger glottis edema that prevents them from air permeability, this clinical picture is pathological and, on the other hand, immune tolerance is not.