Immunology Flashcards
7 cards from real Biology Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Immunology flashcards as text
Which cytokine is known as the 'master regulator' of Th1 cell differentiation?
Answer: IL-12
IL-12, produced mainly by dendritic cells and macrophages, drives naive T cells to differentiate into Th1 cells that produce IFN-γ.
What is the significance of the RAG1 and RAG2 enzymes in lymphocyte development?
Answer: They catalyze V(D)J recombination to generate diverse antigen receptors
RAG1 and RAG2 (recombination activating genes) are essential for V(D)J recombination, the process that generates the enormous diversity of B cell and T cell receptors.
Which complement protein forms the membrane attack complex (MAC)?
Answer: C5b-9
The membrane attack complex (MAC) is formed by complement proteins C5b, C6, C7, C8, and multiple C9 molecules, creating pores in target cell membranes.
A patient develops symptoms 48–72 hours after exposure to an antigen. Which type of hypersensitivity is most likely?
Answer: Type IV (delayed-type)
Type IV hypersensitivity is T cell-mediated and takes 48–72 hours to develop, as seen in contact dermatitis and the tuberculin skin test.
What distinguishes central tolerance from peripheral tolerance in the immune system?
Answer: Central tolerance eliminates self-reactive cells during development; peripheral tolerance controls mature autoreactive cells
Central tolerance occurs in the thymus (T cells) and bone marrow (B cells) to eliminate strongly self-reactive lymphocytes during development, while peripheral tolerance controls any self-reactive cells that escape into circulation.
Which surface marker distinguishes naive B cells from plasma cells?
Answer: CD138 (syndecan-1)
Plasma cells (terminally differentiated antibody-secreting B cells) are identified by high expression of CD138 (syndecan-1), while naive B cells express CD19 and CD20.
What is the role of the AIRE (autoimmune regulator) gene in central tolerance?
Answer: It drives expression of tissue-specific antigens in thymic medullary epithelial cells for negative selection
AIRE allows thymic medullary epithelial cells to express peripheral tissue antigens, enabling deletion of T cells that would react against those tissues in the periphery.