ATI LPN
Immune System Questions Questions
Question 1 of 4
Which one of the following sequences is appropriate for testing a patient for antibody against the AIDS virus with the ELISA procedure?
Correct Answer: B
Rationale: The correct sequence for testing a patient for antibody against the AIDS virus with the ELISA procedure is B. Step 1: HIV antigen is immobilized on a solid surface. Step 2: Patient's serum containing antibodies is added. Step 3: Enzyme-labeled antibody against human gamma globulin is added to detect patient antibodies. Step 4: Enzyme substrate is added to produce a measurable signal. This sequence allows for the detection of patient antibodies against the HIV antigen. Choices A, C, and D are incorrect because they do not follow the correct order of steps for an ELISA test. In these options, the order of the components is not suitable for detecting antibodies in the patient's serum effectively.
Question 2 of 4
In setting up a complement fixation test for antibody, the reactants should be added in what sequence?
Correct Answer: D
Rationale: The correct sequence for setting up a complement fixation test for antibodies is as follows: Ag + patient's serum + C (complement) / wait / + EA (erythrocyte antigen). This sequence ensures that the patient's serum containing antibodies is mixed with the antigen (Ag) first to allow for antibody-antigen binding. Then, complement (C) is added to the mix to activate the complement fixation process. Finally, erythrocyte antigen (EA) is added to observe any hemolysis indicating the presence of antibodies. This order is crucial for accurate test results. Incorrect choices: A: Incorrect sequence, as patient's serum should be mixed with Ag first. B: Incorrect sequence, as C should be added before EA. C: Incorrect sequence, as EA should be added last for hemolysis observation.
Question 3 of 4
Your patient became ill 10 days ago with a viral disease. Laboratory examination reveals that the patient's antibodies against this virus have a high ratio of IgM to IgG. What is your conclusion?
Correct Answer: A
Rationale: The high ratio of IgM to IgG antibodies indicates an acute infection, as IgM is produced initially and declines over time while IgG increases for long-term immunity. Choice A is correct because a high IgM to IgG ratio suggests a recent encounter with the virus, making it unlikely the patient has been previously exposed. Choices B, C, and D are incorrect because they do not address the specific antibody response pattern seen in acute viral infections.
Question 4 of 4
Which one of the following is the BEST method of reducing the effect of graft-versus-host disease in a bone marrow recipient?
Correct Answer: C
Rationale: The correct answer is C: removing mature T cells from the graft. Graft-versus-host disease (GVHD) occurs when the donor's T cells attack the recipient's tissues. Removing mature T cells from the graft can reduce the risk of GVHD while preserving the graft's ability to engraft and function. Matching complement components (choice A) may help in other transplant scenarios but not specifically in reducing GVHD. Administering alpha interferon (choice B) is not a standard method for preventing GVHD. Removing pre-B cells (choice D) does not target the cells responsible for GVHD.