Suggested Answers to Case Study
Chapter 15, Innate and Adaptive Immunity
A 45-year-old man is admitted to the emergency department with a laceration on
his left arm. In collecting his history records, the nurse notes he has never had an
immunization to tetanus. Due to the nature of the laceration, the patient needs to
have immediate protection from tetanus to prevent possible exposure to the
disease from the dirty laceration.
1. Compare and contrast active versus passive immunity.
Active immunity requires the individual’s immune system is actively involved in
the production of the immune response. In this case, a patient given a tetanus
toxoid injection is given a small amount of antigen. The immune system will
respond actively to the antigen and produce T and B lymphocytes, which will be
sensitized to the antigen. This response will also produce memory cells which will
recognize the antigen when exposed again and will accelerate the immune
response and clearing of the antigen.
Passive immunity does not require the individual’s own immune system is active.
When you given passive immunity, you are given immune cells that have already
been exposed to the antigen and have been developed in another individual or
by a laboratory. These cells will provide protection for a short period of time but
will not provide a memory component.
2. If this patient needs immediate protection against the disease, what type of
immunity will the nurse expect to give to the patient and why?
The important learning point here is that for an individual to build up total
immunity to tetanus, if they have not been exposed or had the immunization, it
will take up to 6 months. This patient is at risk immediately due to the nature of
the laceration. It is important to give passive immediate immunity to protect him
until his own immune system is able to build an active response.
Tetanus toxoid, which is the active antigen, is given to begin stimulation of the
immune system; this is to start active immunity.
Tetanus immunoglobulin is given immediately as this is providing passive
immunity, which will protect the patient until his immune system is able to
complete the immune response. Tetanus immunoglobulin contains
immunoglobulins that were exposed to the tetanus antigen. These immune cells
will work in this individual for up to 3 months and can provide immediate
protection. These cells do not provide a memory component. The use of both
tetanus toxoids to stimulate active immunity, and tetanus immunoglobulin to
stimulate passive immunity provides immediately protection and begins the
memory component that will protect on the next exposure
3. When this patient is given tetanus toxoid, the immunization utilized for
protection against tetanus, he is given a substance that will cause an active
immune response. Which two types of lymphocytes will be involved in this
immune response and how does each stimulate the immune response?
Remember when you give tetanus toxoid you are giving a small amount of the
tetanus antigen. The immune system will recognize the antigen as foreign, and
will stimulate both cell mediated and humoral immunity. The cell-mediated arm of
the immune system will produce T lymphocytes that are sensitized to the antigen.
Cytotoxic T lymphocytes will destroy the antigen, and T-memory cells will stay in
the circulation and will recognize the antigen if the patient is exposed again. The
humoral arm of the immune system produces B lymphocytes, which will be
transformed into B-memory cells and plasma cells, which produce the five
classes of immunoglobulins. Remember the B lymphocyte is not the active cell
on this side of the equation. The immunoglobulins are responsible for the ability
to destroy to antigen.
4. In 5 years this same patient returns to the emergency room with another
laceration. In obtaining the nursing history, you realize he has had all the
required immunizations against tetanus. How will the concept of “memory cells”
impact your understanding of what you need to do to protect the patient at his
time?
Memory cells will stimulate the secondary immune response on the second
exposure. Remember both sensitized B and T lymphocytes were produced on
the first exposure. These cells produced memory cells that recognize the antigen
and will stimulate an immediate more effective response when exposed again.
This patient does not need passive immunity and only needs an active
restimulation of the immune system every 10 years.