Immune System MCQ Quiz in मल्याळम - Objective Question with Answer for Immune System - സൗജന്യ PDF ഡൗൺലോഡ് ചെയ്യുക

Concept:

• A network of tissues, veins, and organs known as the lymphatic system collaborates to transport lymph, a colorless, watery fluid, back into your circulatory system (your bloodstream).
• Each day, your body's arteries, smaller arteriole blood vessels, and capillaries carry about 20 liters of plasma.
• About 17 liters are then returned to circulation through veins after nourishing the body's cells and tissues and collecting their waste products. The remaining three liters permeate your body's tissues via capillaries.
• The lymphatic system gathers this extra fluid, which is now known as lymph, from your body's tissues and transports it to various locations before returning it to your bloodstream.
• The lymphatic system has many functions. Its key functions include:
  • Maintains fluid levels in your body: As was just mentioned, the lymphatic system gathers any extra fluid that drains from your body's cells and tissues before returning it to your bloodstream, which then circulates around your body.
  • Absorbs fats from the digestive tract: Lymph transfers fat- and protein-containing fluids from your intestines back to your bloodstream.
  • The immune system includes the lymphatic system, which defends your body from external pathogens.
  • Protects your body against foreign invaders: It creates and releases immune cells such as lymphocytes (white blood cells), which track and eventually eliminate any external invaders including bacteria, viruses, parasites, and fungi that may infiltrate your body.
  • transports and expels aberrant cells and debris from the lymph.

Explanation:

• The body's fluid balance is maintained, immune cells are transported, and waste and toxins are removed from tissues by the lymphatic system, which is a network of veins, tissues, and organs.
• Fluid homeostasis, or maintaining the proper fluid balance between the blood and tissues, is one of the lymphatic system's fundamental tasks.
• This is accomplished through the flow of lymph, a transparent fluid that travels through the lymphatic vessels and is essential in flushing out waste and excess fluid from tissues and reintroducing them to the bloodstream.
• Making up a crucial component of the immune system, the lymphatic system aids in the body's defense against bacteria, viruses, and other pathogens.
• Immune cells in lymph nodes, which are tiny, bean-shaped organs located all over the body, may recognize and eliminate potentially hazardous pathogens and foreign chemicals.
• In addition to performing these tasks, the lymphatic system aids in the digestive system's ability to absorb fats and nutrients that are fat-soluble. These nutrients are taken from the small intestine by specialized lymphatic capillaries known as lacteals and transported to the bloodstream.
• The exchange of gases in tissues is not directly regulated by the lymphatic system, though.
• The respiratory system, which is in charge of bringing oxygen into the body and expelling carbon dioxide, performs this duty largely. The lymphatic system does not take part in the exchange of gases, but it does aid in the removal of waste materials from tissues.

The correct answer is Option 2 i.e.He will be equally sensitive as first encounter because there would be no recall of the first encounter.

Key Points

• ​Immunity is defined as the state of being insusceptible to a particular disease.
• Types of Immunity:

1. Natural Active immunity:
   • It is a type of immunity where the body has to work to develop the appropriate response by producing antibodies.
2. Natural passive:
   • It is a type of immunity where the body gains antibodies from an external source but it does not produce antibodies by inducing a response.
   • For example, an infant receives antibodies from breast milk.
3. Artificial active immunity:
   • ​​Artificial immunity is an alternate form of immunity that is acquired from vaccination.
   • In the case of artificial active immunity, the antigen is injected into the body, for example, inactivated bacterial toxin. 
4. Artificial passive immunity:
   • ​​If antibodies or antitoxins are injected in the vaccination, then this is called artificial passive immunity.
   • In artificial passive immunity, the body does not produce any response and hence, memory is not developed. 

Explanation:

• Antitoxins are artificial passive immunity where antibodies against the venom are injected into the body to counteract the venom of the snake.
• It does not lead to activation of the immune response in the body as in the case of artificial active immunity.
• Hence, memory will not be developed in the body and Suresh will be sensitive to the toxin and he will again have to take antitoxin.

Hence, the correct answer is option 2.

The correct answer is Option 4 i.e.role of dendritic cells in adaptive immunity

Key Points

Acquired immunological tolerance:

• This refers to the immune system's ability to recognize and tolerate the body's own cells and tissues, while still being able to mount an effective immune response against foreign substances.
• This process is essential for preventing autoimmune diseases, in which the immune system mistakenly attacks the body's own cells.

Role of dendritic cells in adaptive immunity:

• Dendritic cells are specialized immune cells that are involved in initiating and regulating adaptive immune responses. 
• Dendritic cells are a type of white blood cell that plays a key role in the immune system's ability to recognize and respond to foreign substances, such as viruses and bacteria.
• Dr. Ralph M. Steinman's research focused on the discovery and characterization of these cells and their role in adaptive immunity.
• Specifically, Dr. Steinman discovered that dendritic cells are important antigen-presenting cells that can activate T cells, a type of immune cell that helps to identify and destroy foreign invaders.
• He found that dendritic cells are able to capture and process antigens, or small pieces of foreign substances, and then present them to T cells in a way that stimulates their activation.
• Dr. Steinman's discovery of dendritic cells and their role in adaptive immunity has had a significant impact on our understanding of how the immune system works and how it can be harnessed to treat diseases such as cancer and autoimmune disorders.
• His work has also led to the development of new vaccines and immunotherapies that target dendritic cells to enhance the body's natural immune response.

The correct answer is IL-4.

Explanation:

High levels of serum IgE and chronic infections with parasitic worms suggest that the patient's immune system is heavily skewed towards a Th2-type response. Each of the interleukins mentioned plays different roles in the immune response:

IL-1: This interleukin is primarily involved in the inflammatory response and is not specifically associated with the production of IgE or the Th2 immune response.

IL-4: This cytokine is crucial for the differentiation of naive T cells into Th2 cells. Th2 cells, in turn, are key players in the promotion of IgE production by B cells. IL-4 not only enhances IgE class switching in B cells but also stimulates the production of other Th2 cytokines like IL-5 and IL-13, which are important in combating parasitic infections, particularly helminths (parasitic worms). Therefore, overactivity of IL-4 would explain both the elevated IgE levels and the chronic parasitic infections in the patient.

IL-6: This cytokine is involved in the acute phase response and is important in the differentiation of B cells into antibody-producing plasma cells. While it plays roles in various immune responses, it is not specifically linked to the production of IgE or parasitic worm infections in the same way as IL-4.

IL-12: This cytokine promotes Th1 differentiation and is important in the defense against intracellular pathogens such as viruses and certain bacteria. Th1 cells are involved in cell-mediated immunity rather than the antibody-mediated immunity characteristic of Th2 responses and IgE production.

Therefore, the interleukin most likely overactive in this patient’s immune response is IL-4.

The correct answer is A - iii, B - i, C - ii, D - iv.

Explanation:

The correct answer is "A" will be protected against both the ancestral strain and the Delta variant.

Explanation:  

Two different types of immune components are transferred to two unrelated recipients:

Recipient "A" receives pooled serum from successfully vaccinated individuals. Serum contains neutralizing antibodies that were generated in response to the ancestral (Wuhan) strain of Covid-19.

• These antibodies likely also offer some protection against related strains like the Delta variant, which shares many spike protein features with the ancestral strain.
• However, the Omicron variant has significant mutations in the spike protein, which make it more resistant to neutralization by antibodies induced by the ancestral strain vaccine.
• Thus, Recipient "A" will have protection against both the ancestral strain and the Delta variant due to the neutralizing antibodies but will not be protected against the Omicron variant.

Recipient "B" receives pooled T cells from vaccinated individuals. These T cells, especially cytotoxic T lymphocytes (CTLs), are specific to the ancestral strain and are less dependent on spike protein variations compared to neutralizing antibodies. However, T cells may not offer the same breadth of protection across variants because of differences in the antigen presentation.

Other Options:

• B" will be protected against ancestral strain but not against the Delta variant: While T cells could protect against the ancestral strain, they may still offer some cross-reactivity to other strains like Delta, as T cell responses tend to recognize more conserved viral elements. So, this option is unlikely.
• "A" will be protected against infection with the Omicron variant: Omicron has extensive mutations in the spike protein, so it is less likely that serum containing antibodies generated against the ancestral strain will protect against Omicron.
• "A" will make antibodies against interferon gamma present in the donor serum: This is not a common or expected response. The transferred serum contains neutralizing antibodies, not interferon gamma, and such immune responses against interferon gamma are not typically seen.

The correct answer is self-antigens in association with self-MHC molecules.

Explanation:

Positive Selection in the Thymus:

• In the thymus, developing T cells (thymocytes) undergo a selection process to ensure that they can properly recognize self-MHC (Major Histocompatibility Complex) molecules.
• During positive selection, thymocytes that successfully bind to self-MHC molecules (with a low affinity) are promoted to survive and mature into functional T cells. This process helps ensure that T cells are capable of recognizing antigens presented by the body’s own MHC molecules, which is crucial for effective immune responses.

Other Options

Foreign antigens in association with self-MHC molecules:

• This describes the process of activation of mature T cells in peripheral tissues, rather than positive selection in the thymus.

Self-antigens in association with foreign-MHC molecules:

• This scenario is not relevant to T cell selection; T cells do not recognize self-antigens in the context of foreign MHC during positive selection.

Foreign antigens in association with TLR ligands:

• Toll-like receptors (TLRs) are involved in innate immunity and do not play a direct role in the positive selection of T cells in the thymus.

Conclusion: Therefore, during positive selection in the thymus, T cells are selected based on their ability to recognize self-antigens in association with self-MHC molecules.

The correct answer is Invariant chain (Ii)

Explanation:

For the presentation of exogenous antigens by Class II MHC molecules:-

• Invariant chain (Ii) is associated with Class II MHC molecules. It binds to the MHC Class II molecule in the endoplasmic reticulum, preventing the binding of endogenous peptides. The invariant chain guides the MHC Class II molecule to the endosomal/lysosomal pathway where it can encounter and bind exogenous peptides after the invariant chain is degraded.
• TAP1 and TAP2 proteins are involved in the presentation of endogenous antigens by Class I MHC molecules, not Class II.
• Proteosome-like subunits LMP2 and LMP7 are also involved in the processing of endogenous antigens for presentation by Class I MHC molecules.

The correct answer is Option 1

Explanation:

P. Anergy is a state in which T cells become inactivated due to an antigen being presented without the necessary second costimulatory signal. This makes the T cell unresponsive to future encounters with the antigen. So, P matches with Unresponsiveness to antigens due to lack of co-stimulatory molecules.

Q. Activation-induced cell death (AICD) is a mechanism through which T cells that have been activated undergo apoptosis after their task (such as fighting an infection) is complete. This helps to ensure that the immune response does not become overactive and that tolerance is maintained by removing these cells after they have served their purpose. This means Q matches with Elimination of activated T-cells after antigen clearance.

R. Receptor editing is a process primarily identified in B cells, where B cells that recognize self-antigens with high affinity undergo further light chain rearrangement to change their specificity. This acts as a mechanism to prevent the emergence of auto-reactive B cells. Therefore, R should match with Elimination of auto-reactive B-cells.

S. Regulatory T-cells (Tregs) play a critical role in maintaining tolerance by suppressing the activation and proliferation of auto-reactive T cells in the periphery. They help prevent autoimmune reactions and maintain immune homeostasis. Hence, S matches with Inhibition of auto-reactive T-cells at periphery.

According to these matches, the correct answer is P-3, Q-1, R-4, S-2.

The correct answer is T-cell anergy

Concept:

• T cells are a type of lymphocyte that play a central role in cell-mediated immunity. They recognize antigens presented by other cells via the T-cell receptor (TCR).
• Co-stimulation is a crucial secondary signal provided by antigen-presenting cells (APCs) necessary for full T-cell activation.
• Without co-stimulation, T cells can become anergic, meaning they become non-responsive to the antigen and cannot proliferate or secrete cytokines effectively.

Explanation:

• Upregulation of B7.1: This is incorrect. B7.1 (CD80) is a co-stimulatory molecule expressed on antigen-presenting cells (APCs) that binds to CD28 on T cells to provide the necessary second signal for T-cell activation. Lack of co-stimulation would not result in upregulation of B7.1 on T cells.
• T-cell apoptosis: This is incorrect. While T-cell apoptosis (programmed cell death) can occur under certain conditions, the absence of co-stimulation typically leads to anergy rather than apoptosis.
• T-cell anergy: This is correct. In the absence of co-stimulation, T cells become anergic, meaning they are functionally inactivated and unable to respond to subsequent encounters with the antigen.
• Upregulation of B7.2: This is incorrect. Similar to B7.1, B7.2 (CD86) is another co-stimulatory molecule on APCs and is not upregulated on T cells in the absence of co-stimulation.