When a T-cell receptor (TCR) interacts with its ligand, what components does it make contact with?

Correct answer: Both the peptide and the MHC molecule

Explanation

T-cell recognition is a dual process. The T-cell receptor must simultaneously recognize features of the antigenic peptide nestled in the MHC groove and features of the MHC molecule's helices that form the groove. This dual recognition is the basis of MHC restriction.

Other questions

Question 1

What is the approximate molecular weight of a single heavy (H) chain in an IgG antibody?

Question 2

What is the approximate molecular weight of a single light (L) chain in an IgG antibody?

Question 3

What is the approximate total molecular weight of an entire IgG antibody molecule?

Question 4

In humans, what is the average ratio of kappa (k) light chains to lambda (l) light chains found in antibodies?

Question 5

In cattle, what is the average ratio of kappa (k) to lambda (l) light chains in their antibodies?

Question 6

How many immunoglobulin (Ig) domains does the heavy chain of a standard IgG antibody contain?

Question 7

An IgG antibody molecule is composed of how many individual polypeptide chains in total?

Question 8

Which proteolytic enzyme cleaves an antibody on the carboxy-terminal side of the disulfide bonds, resulting in one F(ab')2 fragment?

Question 9

Limited digestion of an antibody molecule with the enzyme papain results in what combination of fragments?

Question 10

The highly variable loops within the V regions of immunoglobulins that form the antigen-binding site are also commonly known by what other name?

Question 11

How many complementarity-determining regions (CDRs) from both the heavy and light chains combine to form a single antigen-binding site on an antibody?

Question 12

The binding of an antibody to its antigen is a reversible, noncovalent interaction. Which of the following is NOT a type of noncovalent force involved in this interaction?

Question 13

What is the term for an antigenic determinant that is composed of amino acids from different parts of a polypeptide chain brought together by the three-dimensional folding of the protein?

Question 14

In a study of the intact West Nile virion, which has 180 theoretical binding sites for the E16 antibody, approximately how many sites were actually able to bind the Fab fragment due to steric hindrance?

Question 15

Which group of animals is known for producing a unique form of antibody called heavy-chain-only IgGs (hcIgGs) that can bind antigens without an associated light chain?

Question 16

A single T-cell receptor (TCR) molecule possesses how many antigen-binding sites?

Question 17

Approximately how many identical T-cell receptor molecules are present on the surface of a single T cell?

Question 18

The ligand recognized by a conventional alpha:beta T-cell receptor is a complex consisting of which two components?

Question 19

What is the typical length in amino acids of the short peptides that are bound by MHC class I molecules?

Question 20

What is the typical minimum length of peptides bound by MHC class II molecules?

Question 21

When a T-cell receptor (TCR) binds to its peptide:MHC ligand, which regions of the TCR primarily make contact with the peptide component of the complex?

Question 22

The T-cell co-receptor CD4 binds to which class of MHC molecules?

Question 23

By what factor does the presence of the CD4 co-receptor enhance a T cell's sensitivity to its specific antigen?

Question 24

MHC class II molecules are normally expressed on which of the following groups of cells?

Question 25

Which cytokine is known to increase the expression of both MHC class I and MHC class II molecules, and can induce MHC class II expression on cells that do not normally have it?

Question 26

What is the term for the five main classes of immunoglobulins, such as IgM and IgG, which are distinguished by the structure of their heavy-chain constant regions?

Question 27

Which structural feature of an antibody is formed by the pairing of the VH and VL domains at the ends of the two arms of the Y-shaped molecule?

Question 28

What is the general term for the specific structure on an antigen that is recognized by an antibody?

Question 29

What is the name of the distinctive structure, consisting of two beta sheets folded onto each other like a sandwich and linked by a disulfide bond, that is characteristic of immunoglobulin V and C domains?

Question 30

According to the variability plot in the provided text, how many distinct hypervariable regions are identified within the V domain of an immunoglobulin heavy chain?

Question 31

What is the term for the less variable portions of an immunoglobulin V domain that are located between the hypervariable regions?

Question 32

The T-cell receptor alpha (TCR-alpha) and beta (TCR-beta) chains are connected to each other by what type of chemical bond?

Question 33

A T-cell receptor consists of two variable (V) regions. How many constant (C) regions does it have?

Question 34

An MHC class I molecule is a heterodimer consisting of a large, membrane-spanning alpha chain noncovalently associated with which smaller, non-membrane-spanning chain?

Question 35

The peptide-binding cleft of an MHC class I molecule is formed by the folding of which two domains?

Question 36

The peptide-binding cleft of an MHC class II molecule is formed by domains from which chains?

Question 37

What is a key structural difference regarding the ends of the peptide-binding cleft between MHC class I and MHC class II molecules?

Question 39

What is the term for the phenomenon where a T cell is only able to recognize its specific peptide antigen when that peptide is bound to a particular MHC allele?

Question 40

The CD8 co-receptor binds to an invariant site on which domain of the MHC class I molecule?

Question 41

Which of the following cell types expresses little to no MHC class I, thereby creating a 'privileged site' where parasites like Plasmodium can live undetected by cytotoxic T cells?

Question 42

Which immunoglobulin class is the most abundant in the serum of a healthy adult human?

Question 43

An immunoglobulin (Ig) domain, which is a repeating structural unit in antibody chains, is approximately how many amino acids long?

Question 44

Which of the immunoglobulin chains are composed of two Ig domains?

Question 45

What are the amino-terminal domains of the heavy and light chains, which together make up the V region of the antibody and determine its antigen-binding specificity, called?

Question 46

What is the term for small molecules that are specifically recognized by an antibody but can only stimulate the production of antibodies when linked to a protein?

Question 47

A minority population of T cells bears a distinct type of T-cell receptor made up of which two chains?

Question 48

In an immunoglobulin molecule, where are the amino acid sequences most variable?

Question 49

The overall structure of an alpha:beta T-cell receptor is most similar to which component of an immunoglobulin molecule?

Question 50

What are the two types of light chains found in immunoglobulins?