ATI RN
PAL Histology Lymphatic System Lab Practical Question 1 Questions
Question 1 of 5
Some viruses have mechanisms to down-regulate MHC class I protein expression on the surface of cells in which the virus is replicating. This immune evasion strategy might prevent effector CD8 cytotoxic T cells from recognizing and killing the virus-infected cells. Would this immune evasion strategy also prevent the initial activation of virus-specific CD8 T cells?
Correct Answer: B
Rationale: DCs cross-present viral peptides , bypassing evasion; not all cells (A, D) or early presentation explain activation.
Question 2 of 5
Which of the following statements regarding antigens and antibodies is false?
Correct Answer: D
Rationale: Antibodies have two antigen-binding sites, not one, making D false; the others are true about antigen-antibody interactions.
Question 3 of 5
Which of the following compounds is produced and secreted by mast cells during an allergic reaction?
Correct Answer: C
Rationale: Mast cells release histamine in allergic reactions, causing symptoms like swelling, not interferon, allergens (triggers), or perforin.
Question 4 of 5
A cytokine that induces multiple effects on different immune cells is said to be.
Correct Answer: A
Rationale: Pleiotropic cytokines (e.g., IL-6) have multiple effects on various cells, unlike autocrine (self-acting), synergistic, or antagonistic.
Question 5 of 5
The predominant antibody isotype in external secretions that can neutralise pathogens and toxins and prevent their interaction with mucosal surfaces is
Correct Answer: A
Rationale: IgA dominates in secretions (e.g., saliva, mucus), neutralizing pathogens at mucosal surfaces.