Nokea
What distinguishes Type V hypersensitivity from Type II?
- A. It is mediated by T cells
- B. Antibodies stimulate receptors instead of destroying them
- C. It involves immune complex formation
- D. It does not involve the immune system
Correct Answer: B
Rationale: The correct answer is B because Type V hypersensitivity involves antibodies stimulating receptors instead of destroying them. In Type II hypersensitivity, antibodies target antigens on cell surfaces, leading to cell destruction. In Type V, antibodies bind to cell receptors, causing abnormal receptor activation. Choices A, C, and D are incorrect because Type V hypersensitivity is not mediated by T cells (A), does not involve immune complex formation (C), and does involve the immune system (D). Therefore, the unique characteristic of Type V hypersensitivity is the stimulation of receptors by antibodies, making choice B the correct answer.
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T cells can recognize
- A. Linear peptides
- B. The shape of antigens
- C. Buried epitopes
- D. Soluble antigens
Correct Answer: B
Rationale: The correct answer is B: The shape of antigens. T cells recognize antigens based on their shape, specifically the conformational structure of the antigen. T cell receptors interact with the surface of antigens, forming a complex based on the shape complementarity. This interaction is crucial for T cell activation and immune response.
A: Linear peptides - While T cells can recognize linear peptides presented by MHC molecules, the primary mode of recognition is through the shape of antigens.
C: Buried epitopes - T cells typically recognize epitopes displayed on the surface of antigens rather than buried within the structure.
D: Soluble antigens - T cells can recognize both soluble and membrane-bound antigens, but the key factor is the shape rather than the solubility of the antigen.
A patient with diarrhea has been diagnosed with Clostridium difficile. Along with standard precautions, which kind of transmission-based precautions will be used when the nurse is caring for this patient?
- A. Droplet precautions
- B. Contact precautions
- C. Isolation precautions
- D. Airborne precautions
Correct Answer: B
Rationale: Clostridium difficile spreads through direct contact with contaminated surfaces or hands. Therefore, contact precautions are necessary to prevent its transmission.
Lymph consists of fluid that:
- A. Is taken up from tissues by lymphatic capillaries
- B. Carries antigens and mature dendritic cells to lymph nodes
- C. Is secreted by lymphocytes
- D. Two of these options are correct
Correct Answer: D
Rationale: Rationale:
1. A is correct as lymph is taken up from tissues by lymphatic capillaries.
2. B is correct as lymph carries antigens and mature dendritic cells to lymph nodes.
3. C is incorrect as lymph is not secreted by lymphocytes.
4. Therefore, D is correct as both A and B accurately describe the components and functions of lymph.
Lysozyme
- A. Helps protecting the eye from pathogens
- B. Is a cationic protein able to bind the negatively charged membrane of bacteria
- C. Can digest the cell wall of bacteria
- D. Is a MAMP
Correct Answer: D
Rationale: Firstly, Lysozyme is a Microbe-Associated Molecular Pattern (MAMP), not a protein. MAMPs are molecules recognized by the innate immune system to trigger immune responses. Lysozyme is not specific to protecting the eye (A), binding membranes (B), or digesting cell walls (C). Therefore, the correct answer is D.
What was Edward Jenner's major contribution to immunology?
- A. Discovering antibodies
- B. Proposing innate immunity theory
- C. Developing the smallpox vaccine
- D. Discovering the germ theory of disease
Correct Answer: C
Rationale: Edward Jenner's major contribution to immunology was developing the smallpox vaccine. He introduced the concept of vaccination by using cowpox to protect against smallpox. This marked the beginning of modern immunization. Discovering antibodies (A) and proposing innate immunity theory (B) were not directly attributed to Jenner. Discovering the germ theory of disease (D) was later proposed by Louis Pasteur and Robert Koch, not Jenner. Overall, choice C is correct as it aligns with Jenner's groundbreaking work in immunization.