Biology

Human Immunity and Blood

2,096 Questions

Human immunity and blood questions cover the physiological mechanisms protecting the body against diseases and the components of blood. Topics include blood groups, cell mediated immunity, monoclonal antibodies, and blood coagulation. These biology topics frequently appear in general science sections of competitive exams.

Blood groupsCell mediated immunityMonoclonal antibodiesBlood coagulationCancer immunology

Human Immunity and Blood Questions

Multiple choice

What is the role of B cells in the maintenance of immune memory?

  1. Producing antibodies against pathogens

  2. Killing infected cells

  3. Releasing cytokines

  4. Activating macrophages
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

B cells contribute to immune memory by producing memory B cells, which remain in the body after an infection and can rapidly produce antibodies upon re-exposure to the same pathogen, providing long-term protection.

Multiple choice

Which type of immune tolerance is responsible for preventing the immune system from attacking the body's own tissues?

  1. Central tolerance

  2. Peripheral tolerance

  3. Natural tolerance

  4. Acquired tolerance
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Central tolerance is the type of immune tolerance that is responsible for preventing the immune system from attacking the body's own tissues. This process occurs in the thymus, where immature T cells are tested for their ability to recognize self-antigens. T cells that react to self-antigens are deleted, while T cells that do not react to self-antigens are allowed to mature and enter the periphery.

Multiple choice

What is the role of regulatory T cells in immune tolerance?

  1. To suppress the immune response to self-antigens

  2. To suppress the immune response to foreign antigens

  3. To promote the immune response to self-antigens

  4. To promote the immune response to foreign antigens
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Regulatory T cells play a critical role in immune tolerance by suppressing the immune response to self-antigens. This prevents the immune system from attacking the body's own tissues.

Multiple choice

What is the role of the thymus in immune tolerance?

  1. To produce T cells

  2. To mature T cells

  3. To select T cells that do not react to self-antigens

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The thymus plays a critical role in immune tolerance by producing, maturing, and selecting T cells that do not react to self-antigens.

Multiple choice

What is the role of the spleen in immune tolerance?

  1. To filter blood for foreign antigens

  2. To produce antibodies

  3. To store immune cells

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The spleen plays a critical role in immune tolerance by filtering blood for foreign antigens, producing antibodies, and storing immune cells.

Multiple choice

What is the role of the gut-associated lymphoid tissue (GALT) in immune tolerance?

  1. To prevent the immune system from attacking commensal bacteria

  2. To produce antibodies against food antigens

  3. To store immune cells

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The GALT plays a critical role in immune tolerance by preventing the immune system from attacking commensal bacteria, producing antibodies against food antigens, and storing immune cells.

Multiple choice

What is the primary mechanism of action of cytokine therapy in immunotherapy?

  1. It directly kills cancer cells

  2. It stimulates the production of antibodies against cancer cells

  3. It enhances the ability of natural killer cells to recognize and attack cancer cells

  4. It blocks inhibitory receptors on T cells
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Cytokine therapy primarily works by stimulating the production of antibodies against cancer cells, enhancing the immune system's ability to recognize and target cancer cells for destruction.

Multiple choice

What is the term for a collection of blood within the skull?

  1. Concussion

  2. Hematoma

  3. Cerebral contusion

  4. Subdural hematoma
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A hematoma is a collection of blood within the skull, which can be caused by a head injury.

Multiple choice

Which cytokine is primarily responsible for the suppressive function of Tregs?

  1. Interferon-gamma (IFN-γ)

  2. Interleukin-2 (IL-2)

  3. Interleukin-10 (IL-10)

  4. Tumor necrosis factor-alpha (TNF-α)
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Tregs produce high levels of IL-10, which is a potent anti-inflammatory cytokine that inhibits the activation and proliferation of other immune cells, thereby suppressing immune responses.

Multiple choice

What is the main mechanism by which Tregs suppress immune responses?

  1. By releasing cytotoxic molecules

  2. By inducing apoptosis in immune cells

  3. By inhibiting the production of pro-inflammatory cytokines

  4. By promoting the differentiation of Th2 cells
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Tregs suppress immune responses primarily by inhibiting the production of pro-inflammatory cytokines, such as IFN-γ and TNF-α, which are key mediators of inflammation and immune activation.

Multiple choice

Which transcription factor is essential for the development and function of Tregs?

  1. T-bet

  2. RORγt

  3. Foxp3

  4. GATA-3
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Foxp3 is a critical transcription factor that plays a central role in the development, differentiation, and function of Tregs. It is essential for the suppressive activity of Tregs and mutations in the Foxp3 gene can lead to autoimmune disorders.

Multiple choice

Which cell surface marker is commonly used to identify Tregs?

  1. CD4

  2. CD8

  3. CD25

  4. CD19
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Tregs are typically identified by the expression of CD25, which is the alpha chain of the interleukin-2 receptor (IL-2Rα). CD25 is a marker associated with regulatory T cell function and is commonly used to distinguish Tregs from other T cell subsets.

Multiple choice

Which type of T cell is most commonly associated with the development of Tregs?

  1. Th1 cells

  2. Th2 cells

  3. Th17 cells

  4. Th9 cells
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Tregs are often generated from naive T cells under the influence of Th2 cytokines, such as interleukin-4 (IL-4) and interleukin-10 (IL-10). These cytokines promote the differentiation of naive T cells into Tregs.

Multiple choice

What is the role of Tregs in transplantation tolerance?

  1. They promote graft rejection

  2. They suppress graft rejection

  3. They produce antibodies against the graft

  4. They promote the differentiation of Th1 cells
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Tregs play a crucial role in promoting transplantation tolerance by suppressing immune responses against the transplanted organ or tissue. They prevent the development of graft rejection and contribute to the long-term acceptance of the graft.

Multiple choice

Which signaling pathway is involved in the suppressive function of Tregs?

  1. Wnt signaling pathway

  2. TGF-β signaling pathway

  3. NF-κB signaling pathway

  4. MAPK signaling pathway
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The TGF-β signaling pathway is a key regulator of Treg function. TGF-β promotes the differentiation and expansion of Tregs and is involved in their suppressive activity. It plays a crucial role in maintaining immune homeostasis and preventing excessive immune responses.