40 Questions
What is the main role of MHC cell surface proteins in the immune system?
Presenting peptide antigens to T cell receptors
Which type of T cells primarily recognize peptides presented by Class I MHC molecules?
CD8+ cytotoxic T cells
What role do T cell receptors (TCRs) play in recognizing antigens?
Binding specifically to peptide-MHC complexes
Where do Class II MHC molecules present peptides derived from?
Extracellular proteins
What is the specificity of the interaction between TCRs and the peptide-MHC complex?
Highly specific
What is the role of immunodominant peptides in the context of T cell activation?
They trigger a strong response from T cells
Which of the following factors influences the selection of immunodominant peptides during antigen processing?
MHC allele expression
What is the primary function of Class I MHC molecules in the antigen processing pathway?
Present peptides to CD8+ CTLs
What is the significance of T cell receptors in recognizing antigens?
They recognize both peptides and MHC molecules
Which statement accurately describes the antigen processing pathway for Class II MHC molecules?
Loads peptides onto newly synthesized Class II MHC molecules
What is the main origin of peptide antigens presented by Class I MHC molecules?
Viral proteins synthesized by infected cells
What is responsible for transporting peptide fragments from the cytosol into the endoplasmic reticulum (ER) in antigen processing for Class I MHC molecules?
TAP complex
What is the key component that makes up Class I MHC molecules along with the heavy chain and β2 microglobulin?
Peptide-binding cleft
Which type of proteins are NOT a source of peptide antigens for Class I MHC molecules?
Ribosomal proteins
During antigen processing for Class I MHC molecules, what degrades intracellular proteins within the cytosol?
Proteasome
Which process ensures that only peptides capable of stable binding to Class I MHC molecules are presented on the cell surface?
Peptide-MHC Association
Where are peptide antigens loaded onto Class I MHC molecules during biosynthesis?
Endoplasmic reticulum
What is the main function of CD8+ cytotoxic T lymphocytes (CTLs) in response to peptide-MHC complexes on the cell surface?
Recognize and eliminate cells presenting specific peptide antigens
Which molecule specifically recognizes and binds to the peptide-MHC complex on the cell surface?
TCR (T cell receptor)
During which stage does the activation of CD8+ CTLs by the peptide-MHC complex occur?
ER-to-Golgi transport
Where do peptide antigens originate for Class II MHC molecules?
From microbial proteins through phagocytosis
What is the role of Class I MHC molecules in the immune system?
Presentation of peptides to CD8+ cytotoxic T lymphocytes
Which cells are responsible for recognizing peptide-MHC complexes on the cell surface?
CD8+ cytotoxic T lymphocytes
What is the function of the Ii protein in the antigen processing pathway?
Prevents loading of cytosolic peptides onto Class II MHC molecules
Which statement accurately describes the origin of peptide antigens for Class I MHC molecules?
They can include misfolded host proteins
Which type of cells express Class II MHC molecules?
B cells
What is the primary role of CD4+ helper T cells?
Produce antibodies
Which cells recognize antigens presented by MHC molecules?
CD4+ helper T cells
What is the main function of CD8+ cytotoxic T lymphocytes?
Destroy infected or abnormal cells
Where do Class I MHC molecules primarily present peptides from?
Intracellular proteins
Which types of T cells recognize peptides presented by MHC Class I molecules?
CD8+ cytotoxic T lymphocytes
Which cells express Class I MHC molecules?
Most nucleated cells
What is the main function of CD4+ T cells in immune responses?
Cytokine release and coordination of immune responses
Which of the following is a characteristic of Class II MHC molecules?
Expressed primarily by antigen-presenting cells (APCs)
What is the specific function of CD8+ cytotoxic T lymphocytes upon recognizing peptide-MHC class I complexes?
Initiate responses against infected or abnormal cells leading to their destruction
What ensures the specificity and fidelity of T cell responses to antigenic peptides presented by MHC molecules?
Dual recognition of the peptide antigen and the MHC molecule by the TCR
Where are protein antigens processed and degraded to generate peptide fragments for presentation to T cells?
In the cytoplasm
What is the role of MHC cell surface proteins in the immune system?
Presenting peptide antigens to T cells for recognition
What is the significance of TCR recognition of both the peptide antigen and the MHC molecule?
It ensures the specificity and fidelity of T cell responses
In T cell recognition, what do the variable regions of the TCR specifically bind to?
Peptide antigens
Explore how the T cell receptor (TCR) recognizes both the peptide antigen and the MHC molecule. Learn about the dual recognition system that ensures specificity and fidelity in T cell responses. Test your knowledge on this crucial aspect of the immune response.
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