Nokea
Alumn is an adjuvant that triggers
- A. TLR4
- B. DAMPs formation
- C. NOD1
- D. TLR9
Correct Answer: B
Rationale: The correct answer is B: DAMPs formation. Alum is known to trigger the release of damage-associated molecular patterns (DAMPs), which are endogenous molecules released by damaged cells. This activation of DAMPs plays a crucial role in initiating and enhancing the immune response. The other choices, TLR4, NOD1, and TLR9, are receptors involved in recognizing specific pathogen-associated molecular patterns (PAMPs) rather than DAMPs. Therefore, they are not directly triggered by alum. This makes choice B the correct answer based on the known mechanism of action of alum as an adjuvant.
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The human immunodeficiency virus (HIV)
- A. Is a retrovirus
- B. Is an RNA virus
- C. Is a lentivirus
- D. All of the above A, B and C
Correct Answer: D
Rationale: Step 1: HIV is a retrovirus because it contains RNA as its genetic material and uses the enzyme reverse transcriptase to convert its RNA into DNA.
Step 2: HIV is an RNA virus because its genetic material is RNA.
Step 3: HIV is a lentivirus which is a subgroup of retroviruses known for causing slow-progressing diseases.
Therefore, the correct answer is D as all statements A, B, and C are true based on the characteristics of HIV.
Which of the following best describes granuloma formation?
- A. IgE-mediated mast cell activation
- B. Persistent recruitment of macrophages around undigested antigens
- C. Deposition of immune complexes in tissues
- D. Complement-mediated cell lysis
Correct Answer: B
Rationale: Granuloma formation is characterized by the persistent recruitment of macrophages around undigested antigens. Initially, macrophages attempt to phagocytose the antigen but fail to digest it completely, leading to the formation of a granuloma. This process is a protective mechanism to isolate the antigen and prevent its spread. IgE-mediated mast cell activation (choice A) is associated with allergic reactions, not granuloma formation. Deposition of immune complexes in tissues (choice C) is linked to immune complex-mediated diseases, not granuloma formation. Complement-mediated cell lysis (choice D) involves the destruction of target cells by the complement system, which is not directly related to granuloma formation.
Which antibody isotype is involved in allergic reactions?
- A. IgG
- B. IgM
- C. IgA
- D. IgE
Correct Answer: D
Rationale: The correct answer is D: IgE. IgE is the antibody isotype involved in allergic reactions. It binds to allergens and triggers the release of histamine and other chemicals, leading to allergic symptoms. IgG (choice A) is involved in long-term immunity, IgM (choice B) is the first antibody produced in response to an infection, and IgA (choice C) is mainly found in mucosal areas and helps prevent pathogens from entering the body. IgE is specifically associated with allergic responses due to its role in triggering the release of inflammatory mediators in response to allergens.
The class of an immunoglobulin
- A. is determined by Class I and Class II major histocompatibility complex proteins
- B. is determined by the carbohydrate attached to the light chain is
- C. determined by the antigen
- D. is determined by the heavy chain type
Correct Answer: D
Rationale: The correct answer is D because the class of an immunoglobulin is determined by the type of heavy chain it possesses. There are five main classes of immunoglobulins (IgG, IgA, IgM, IgD, IgE) which are defined by the heavy chain constant region. Different heavy chain types result in different effector functions and biological properties. Choices A, B, and C are incorrect because the class of an immunoglobulin is not determined by Class I and Class II major histocompatibility complex proteins, carbohydrate attached to the light chain, or the antigen. These factors may influence the function or specificity of the antibody, but they do not determine its class.
Which represents a correct grouping with respect to the target of an immune response, immune response strength, and resulting health status?
- A. Self-antigen, weak response, autoimmune disease
- B. Pathogen, strong response, recurrent infection
- C. Tumour antigen, weak response, cancer
- D. Transplanted organ, strong response, graft acceptance
Correct Answer: C
Rationale: Rationale:
1. Tumor antigens are non-self antigens that trigger a weak immune response due to immune tolerance.
2. Weak immune response against tumor antigens may lead to uncontrolled cell growth, resulting in cancer.
3. Strong immune responses are typically mounted against pathogens to clear infections.
4. Self-antigens should not trigger immune responses to prevent autoimmune diseases.
5. Transplanted organs can elicit strong immune responses leading to rejection, not acceptance.
Summary:
A - Incorrect: Self-antigens should not elicit immune responses to prevent autoimmune diseases.
B - Incorrect: Pathogens typically trigger strong immune responses to clear infections, not recurrent ones.
D - Incorrect: Transplanted organs often lead to strong immune responses and rejection, not acceptance.