Immune System MCQ Quiz in मराठी - Objective Question with Answer for Immune System - मोफत PDF डाउनलोड करा

Key Points

•  Tetanus is a serious bacterial infection caused by Clostridium tetani, a bacterium commonly found in soil and animal feces.
• The infection typically occurs when spores of C. tetani enter deep wounds, especially puncture wounds, burns, or open fractures.
• Clostridium tetani produces a potent neurotoxin called tetanospasmin.
• This toxin interferes with nerve signaling, leading to muscle stiffness and spasms, which can be severe and life-threatening.
• Symptoms of tetanus infection can include muscle stiffness, jaw clenching (lockjaw), difficulty swallowing, muscle spasms, fever, and even respiratory failure if left untreated.
• The primary way to prevent tetanus is through vaccination with the tetanus toxoid vaccine, commonly known as the tetanus vaccine.

Important Points Tetanus Toxoid Vaccine

• Purpose
  • The tetanus toxoid vaccine is designed to stimulate the immune system to produce protective antibodies against the tetanus toxin.
  • It does not contain live bacteria but rather inactivated tetanus toxin (toxoid).
• Immunization Schedule
  • Tetanus vaccination is typically administered as part of a series of shots during childhood, with booster shots recommended every ten years throughout one's life. 
  • Boosters are especially crucial for individuals with wounds or injuries that could introduce tetanus bacteria.
• Mechanism of Action
  • When a person receives the tetanus toxoid vaccine, the immune system recognizes the inactivated tetanus toxin as foreign and produces antibodies against it.
• Immune Memory
  • These antibodies remain in the body, providing long-lasting immunity.
  • If the person is exposed to the actual tetanus bacteria in the future, their immune system can quickly recognize and neutralize the toxin.
• Importance of Vaccination
  •  Tetanus is a potentially deadly disease, and vaccination is the most effective way to prevent it.
  • Prompt administration of the tetanus vaccine after a wound or injury that could introduce the bacteria is critical to prevent the development of tetanus.

Additional Information

•  DNA Vaccine
  • DNA vaccines use a small piece of genetic material, usually a plasmid containing a specific gene from the target pathogen.
  • The DNA is introduced into the body, often through an injection.
  • Cells in the body then use the DNA to produce a harmless piece of the pathogen, such as a viral protein.
  • The immune system recognizes the foreign protein and mounts an immune response, including the production of antibodies.
• Recombinant Vector Vaccine
  • Recombinant vector vaccines use harmless viruses or bacteria (vectors) to carry genes from the target pathogen.
  • The vector is modified to carry genes that code for specific pathogenic proteins. 
  • When the vaccine is administered, the vector delivers these genes to cells in the body.
  •  Cells use the delivered genes to produce the pathogen's proteins, triggering an immune response. The immune system generates antibodies and immune memory.
  • Example: some COVID-19 vaccines.
• Subunit Vaccine
  • Subunit vaccines contain only a part (subunit) of the pathogen, such as a protein or sugar molecule.
  • The selected subunit is isolated from the pathogen and used in the vaccine.
  • When the subunit is introduced into the body, it stimulates an immune response. The immune system produces antibodies and immune memory specific to the subunit.
  • Example: Hepatitis B vaccine.
• Toxoid Vaccine
  • Toxoid vaccines are designed to protect against diseases caused by bacterial toxins.
  • The toxins produced by certain bacteria are chemically modified or inactivated to make them non-toxic (toxoids).
  • When the toxoid vaccine is administered, the immune system recognizes the inactivated toxin as foreign. It generates antibodies against the toxin.
  • Example: Tetanus vaccine.

The correct option is option 4: Toxoid vaccine

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 VDJ recombination

Explanation:

• Isotype switching, also known as class switch recombination (CSR), is a biological process that allows a B cell to change the class of antibody it produces while retaining the specificity for the antigen. This process enables the immune system to tailor its response to different pathogens.
• During isotype switching, a B cell changes its production of IgM antibodies to another type, such as IgE, IgG, or IgA, depending on the signals it receives. This involves complex molecular mechanisms.
• VDJ recombination is a process that occurs during the early stages of B cell development in the bone marrow, where variable (V), diversity (D), and joining (J) gene segments are rearranged to create a unique antigen-binding site for the immunoglobulin molecule. This process is essential for generating the initial diversity of antibodies but is not involved in isotype switching.
  • ​Isotype switching only alters the constant region of the antibody (which determines the antibody class) and not the variable region (which determines antigen specificity). Therefore, VDJ recombination is NOT required for isotype switching.
• Double-stranded break repair: Isotype switching involves double-stranded DNA breaks in the switch regions of immunoglobulin genes. These breaks are repaired through DNA repair mechanisms, which are essential for the recombination process that facilitates the switch from one antibody class to another. This step is required for isotype switching.
• Cell division: Isotype switching occurs in activated B cells, which undergo cell division as part of their activation and proliferation. This step is important for producing sufficient numbers of B cells capable of secreting antibodies of the desired isotype. 
• T cell cytokines: T helper cells play a crucial role in providing cytokine signals (e.g., IL-4 for IgE switching) that guide B cells in determining which antibody class to switch to. 

The correct answer is A and B

Concept:

• Pathogens have evolved various mechanisms to evade the host's innate and inflammatory immune responses. These mechanisms allow them to persist in the host, avoid detection, and establish infections.
• Some of these evasion strategies include mutations in pathogen-associated molecular patterns (PAMPs) to avoid recognition by Toll-like receptors (TLRs), escaping lysosomal degradation, and suppression of key immune signaling pathways.

Explanation:

Statement A: The flagellin of Proteobacteria has a mutation that prevents it from being recognized by Toll-like receptors (TLRs).

• This is a correct statement. TLRs are pattern recognition receptors (PRRs) that detect microbial components such as flagellin, a structural protein of bacterial flagella.
• Some Proteobacteria have evolved mutations in their flagellin that prevent recognition by TLR5, helping them evade immune responses.

Statement B: The lipopolysaccharides of Helicobacter have mutations that prevent it from being recognized by TLRs.

• This is also correct. Lipopolysaccharides (LPS) are a key component of the outer membrane of Gram-negative bacteria and are typically recognized by TLR4.
• Helicobacter species (e.g., Helicobacter pylori) can modify their LPS structure to avoid recognition by TLR4, thus evading immune detection and promoting chronic infection.

Statement C: M. tuberculosis escapes from the phagosome to the cytosol, thereby avoiding degradation by lysosomal enzymes.

• This is incorrect. M. tuberculosis does not escape to the cytosol; instead, it inhibits phagosome-lysosome fusion, allowing it to survive and replicate within the phagosomal compartment of macrophages.

Statement D: Influenza virus produces Yop protein that inhibits inflammasome activity.

• This is incorrect. Yop proteins are produced by Yersinia species, not the influenza virus. Influenza virus employs other mechanisms to modulate the immune response, such as suppressing interferon production.

Statement E: S. typhi encodes a protein that binds Type I IFNs and prevents them from binding to the IFN receptor.

• This is incorrect. While Salmonella typhi has evolved mechanisms to evade the immune response, binding and inhibiting Type I IFNs is not one of them.

The correct answer is They are responsible for immune responses to blood-borne pathogens.

Explanation:

• Peripheral lymph nodes are small, bean-shaped structures that are part of the lymphatic system. They play a crucial role in filtering lymph fluid and initiating immune responses.
• They are strategically located throughout the body to monitor and respond to pathogens that enter through tissues, such as skin and mucosal surfaces.
• Unlike the spleen, which is specialized for immune responses to blood-borne pathogens, peripheral lymph nodes primarily focus on tissue-derived antigens.
• They are responsible for immune responses to blood-borne pathogens: This statement is incorrect because immune responses to blood-borne pathogens are primarily mediated by the spleen, not peripheral lymph nodes. The spleen filters the blood and is specialized for detecting and responding to blood-borne pathogens. Peripheral lymph nodes, on the other hand, are involved in immune responses to pathogens that enter through tissues.

Other Options:

• They contain fibroblast reticular cells that form a conduit system to guide cell movement within the node: This statement is correct. Fibroblast reticular cells create a structural network within lymph nodes, helping guide immune cells such as T cells and dendritic cells to appropriate locations for efficient immune responses.
• T cells encounter an antigen presented on dendritic cells in the paracortex of lymph nodes: This statement is correct. The paracortex is a specialized area within lymph nodes where T cells interact with antigen-presenting dendritic cells. This interaction is crucial for initiating adaptive immune responses.
• They contain B cells in special areas called follicles: This statement is correct. B cells are housed in lymph node follicles, where they can encounter antigens and undergo processes such as activation, proliferation, and differentiation into antibody-producing plasma cells.

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.