Finally done.

That's it. Im finally done with Immunology. It's unbelievable to find out that there are so many things which we are expected to know but sadly I havent heard mentioned in class. Time to be more proactive Julian! Anyway, here are some sample test questions from the end of the Immunology chapter. If you can get any of them right, good job!:) I also include the answer explanation after the question and bear with me because I will be explaining in my own words (actually just for me to revise:P)


1. Haemophilus Influenza and Neisseria meningitidis both possess a polysaccharide outer capsule. Effective vaccination against these species results in the generation of antibodies that recognize the polysaccharide capsule. Which of the following explains best why the childhood vaccines for H. Influenza type B and N. meningitidis serogroup C are composed of a polysaccharide coat conjugated to a protein carrier.

(a) The protein carrier increases the half life of vaccine
(b) The protein carrier increases the production of IgE immunoglobulins which confer protection
(c) The protein carrier makes the vaccine less virulent and thus decreases the risk of a child developing disease form the immunization
(d) The protein carrier is added to recruit T lymphocyte help and increase antibody production.


Ans: D
Exp: Polysaccharides like many other bacterial antigens are thymus-independent antigens. This means they can cross link the IgM receptors present on the B cell stimulating them to produce IgM without the need for a T lymphocyte to act it. The protein carrier however allows the B cell to present the antigen as recognizable for the T cell thus eliciting a T lymphocyte response as well.


2. Women have about a 2.7 times greater lifetime risk of developing at least one autoimmune disease than men. Which of the following statements, if true, would support the higher rate of systemic lupus erythematosus in women than in men?

(a) Androgens such as testosterone have an inhibitory role in the process of clearing immune complexes.
(b) Both estrogen and androgens have the same potency in inhibiting the clearing of immune complexes.
(c) Estrogen has an inhibitory role in the process of antibody production of B cells
(d) Estrogen has an inhibitory role in the process of clearing immune complexes
(e) Estrogen has a stimulatory role in the process of clearing immune complexes.

Ans: D
Exp: Actually this question is rather straightforward and can be solved just by simple reasoning. Answers A-D all point to the opposite outcome. SLE is a type III hypersensitivity disease. Autoantibodies bind to self antigens and form immune complexes that activate complement, which we all know is a potent activator of neutrophils. Estrogen inhibits the clearing of these complexes hence the greater risk of developing autoimmune diseases.

3. A 23 year old woman comes to the physician for a routine checkup. She has generally been well over the past year although she notes that she has had a few falls recently. On physical examination, a spider angioma is found on her skin. Blood is drawn for laboratory evaluation. The results show that the woman has very low levels of IgA. Based on her presentation, this patient will most likely also present with which of the following symptoms?

(a) Cerebellar problems
(b) Granulomas
(c) Low levels of all other immunoglobulin isotypes
(d) Tetany

Ans: A
Exp: The lady suffers from a disease that is known as Ataxia-telangiectasia. It is due to a defect in DNA repair enzymes. Spider angiomas and ataxia are hallmarks for this disease. Thrombocytopenia can also be observed.

The answer cannot be B because granulomas are seen in another disease known as Chronic Granulomatous Disease. This disease is due to the defiency of NADPH oxidase which results in failure to produce oxygen radicals which we all know is crucial in myeloperoxidase-dependent intracellular killing

The answer also cannot be C because that refers to Bruton's aggamaglobulinemia. It is a X-linked disease and therefore only presents in males. Patient is a 23 year old woman;)

The answer cannot be D because tetany is one of the clinical manifestations of DiGeorge's syndrome. We should know that DiGeorge syndrome is due to the failure of the third and fourth pharyngeal pouches to develop which lead to the absence of the thymus and parathyroid glands. Hypocalcemia is a result and can present with tetany.

Goodnight guys:)