Let's Test Your Immunology Knowledge

A Hepatitis B subunit vaccine refers to a vaccine that uses only a particular component of the virus, specifically proteins, to stimulate an immune response. This means that the vaccine does not contain the entire component of the virus, but rather focuses on specific proteins that can trigger an immune response and provide protection against Hepatitis B.

Adjuvants are helper substances that are used in conjunction with a vaccine to induce inflammation. They enhance the body's immune response to the vaccine by stimulating the immune system and increasing the effectiveness of the vaccine. Adjuvants can be added to vaccines to improve their efficacy, increase the duration of immune responses, and reduce the amount of antigen required in the vaccine. They help to enhance the immune response and provide longer-lasting protection against the targeted disease.

Type IV hypersensitivity is characterized by a T cell-mediated immune response. Unlike other types of hypersensitivity reactions, which involve antibodies (IgG, IgE, and IgM) or complement proteins, Type IV hypersensitivity is initiated and mediated by T cells. This type of immune response is delayed and occurs when T cells recognize and respond to antigens presented by antigen-presenting cells. It is commonly associated with delayed hypersensitivity reactions, such as contact dermatitis and certain autoimmune diseases.

The correct answer is Type III- serum sickness. Serum sickness is a type III hypersensitivity reaction, which occurs when the immune system overreacts to certain medications or foreign substances. This reaction is characterized by the formation of immune complexes in the blood, which can lead to symptoms such as fever, rash, joint pain, and swollen lymph nodes. Type IV hypersensitivity, on the other hand, is a delayed hypersensitivity reaction that involves T cells and is commonly associated with allergic contact dermatitis. Type II hypersensitivity is characterized by the destruction of cells or tissues by antibodies, and type I hypersensitivity is an immediate allergic reaction mediated by IgE antibodies.

The most common areas of the body where immune complex deposition or damage occurs are the kidneys, blood vessels, and joints. Immune complexes are formed when antibodies bind to antigens, and if these complexes are not properly cleared by the immune system, they can deposit in various tissues and cause inflammation and damage. In conditions like lupus or vasculitis, immune complexes can accumulate in the kidneys, leading to glomerulonephritis. Similarly, immune complex deposition in blood vessels can result in vasculitis, while in joints it can cause inflammation and damage, as seen in conditions like rheumatoid arthritis.

When a mother is given RhoGam prior to her pregnancy to protect from the formation of IgG anti-Rh antibodies, it is a form of passive immunization. Passive immunization involves the transfer of pre-formed antibodies from one individual to another, providing immediate protection against a specific antigen without the need for the recipient's immune system to produce its own antibodies. In this case, RhoGam contains anti-Rh antibodies that can prevent the mother's immune system from producing IgG anti-Rh antibodies, which could cause harm to the fetus in future pregnancies.

CD8 T cells are strongly reactive to foreign MHCI because it did not go through negative selection. Negative selection is a process in the thymus where T cells that recognize self-antigens are eliminated to prevent autoimmunity. In this case, the skin graft is foreign tissue and has different MHCI molecules compared to the patient's own cells. Since the T cells did not encounter these foreign MHCI molecules during negative selection, they are not tolerant to them and will mount an immune response against the graft. This leads to the rejection of the skin graft by the patient's immune system.

In Type III hypersensitivity, IgG binding with the antigen activates the complement pathway. This activation leads to the formation of C3a and C5a components. These components are potent inflammatory mediators that cause inflammation to occur. The antigen-antibody complex alone is not sufficient to cause inflammation; it is the activation of the complement pathway and the subsequent release of C3a and C5a that play a crucial role in the inflammatory response.

If John has received the tetanus vaccine before, his symptoms would likely be inflammation in the area of the shot because his IgG will bind quickly to the antigen in the vaccine. This is because the immune system would recognize the antigen from the previous vaccination and mount an immune response, leading to inflammation at the injection site.

A PPD test (type IV) cannot produce an immune response because it is a purified protein. Purified proteins are processed in a way that removes any components that could potentially cause inflammation or trigger an immune response. Therefore, the purified protein does not have the ability to stimulate the immune system and produce an immune response.

Maryann's rash is likely due to her previous exposure to poison ivy. When she pulled the plants in her garden, she may have come into contact with the urushiol oil present in poison ivy, which can cause an allergic reaction in individuals who are sensitized to it. This is supported by the fact that the rash appeared two days after her gardening activity, which is consistent with the delayed onset of symptoms after exposure to urushiol.

When someone has serum sickness, the correct sequence of events is as follows: the patient is injected with anti-venom horse antibodies, which leads to the patient producing human anti-horse antibodies. This triggers the activation of complement, a part of the immune system. Symptoms of serum sickness typically appear 7-10 days later.

The correct answer is that the immunological cause of the muscle weakness in this patient with MS is the activation of macrophages from activated Th1 cells, which is activated by the macrophage with myelin basic protein. In MS, the immune system mistakenly attacks the myelin sheath, the protective covering of nerve fibers in the central nervous system. This immune response involves the activation of T cells, specifically Th1 cells, which release pro-inflammatory cytokines that activate macrophages. These activated macrophages then target and destroy the myelin sheath, leading to the muscle weakness experienced by the patient.

Live-attenuated vaccines are made from weakened forms of the virus or bacteria that cause the disease. When administered, these vaccines stimulate a strong immune response in the person vaccinated, leading to the development of active immunity. This means that the person's immune system recognizes the weakened virus or bacteria and produces antibodies to fight against it. Live-attenuated vaccines are known to be very effective and provide long-lasting immunity, often lasting for many years or even a lifetime. Unlike some other vaccines, they generally do not require repeated booster doses.

Formalin is used in vaccines to aid in purifying and inactivating toxins. It is a solution of formaldehyde, a chemical that can kill bacteria and viruses by cross-linking their proteins and nucleic acids. By adding formalin to a vaccine, the toxins produced by bacteria can be chemically modified and rendered harmless while still maintaining their ability to stimulate an immune response. This allows the body to recognize and develop immunity against the toxin without being harmed by its toxic effects.