Immunology Questions

T cells and B cells require MHC molecules for the recognition of peptide antigens.TrueFalse

The primary reason for transplant rejections is due to differences in _____ between donor and recipient.CD3MHC moleculesT-cell receptor α chainsγ:δ T cellsβ2-microblobulin.

Which of the following statements is TRUE regarding TCR structure and function?There are three types of TCRs and they are given the following namesTCR rearrangement is completed in the bone marrow before the developing T cells reach the thymusTCRs undergo somatic hypermutation in the thymus but do not undergo isotype switchingTCR gene segments are recombined by RAG proteins and the RAG proteins are similar to transposases found in virusesTCRs are associated with the Ig and Ig co-receptors which help with the signal transduction process

T-cell receptors interact not only with peptide anchored in the peptide-binding groove of MHC molecules, but also withanchor residuespeptide-binding motifvariable amino acid residues on α helices of the MHC moleculeβ2-microglobulininvariant chain.

Which is the most likely reason that HIV-infected people with heterozygous HLA loci have a delayed progression to AIDS compared with patients who are homozygous at one or more HLA loci?The greater number of HLA alleles provides a wider variety of HLA molecules for presenting HIV-derived peptides to CD8 T cells even if HIV mutates during the course of infection.Heterozygotes have more opportunity for interallelic conversion and can therefore express larger numbers of MHC alleles.Directional selection mechanisms favor heterozygotes and provide selective advantage to pathogen exposure.As heterozygosity increases, so does the concentration of alloantibodies in the serum, some of which cross-react with and neutralize HIV.

Which of the following describes the sequence of events involved in the processing of peptides that will be presented as antigen with MHC class II?protease activity →removal of CLIP from MHC class II →binding of peptide to MHC class II →endocytosis →plasma membraneendocytosis →protease activity →removal of CLIP from MHC class II →binding of peptide to MHC class II →plasma membraneremoval of CLIP from MHC class II →binding of peptide to MHC class II →protease activity →endocytosis →plasma membranebinding of peptide to MHC class II →endocytosis →removal of CLIP from MHC class II →protease activity →plasma membraneplasma membrane →endocytosis →protease activity →removal of CLIP from MHC class II →binding of peptide to MHC class II.

The _____ refers to the complete set of HLA alleles that a person possesses on a particular chromosome 6.isoformisotypeoligomorphallotypehaplotype

Link between Nonspecific and Specific Immune System

Peptides that bind to a particular MHC isoform usually have either the same or chemically similar amino acids at two to three key positions that hold the peptide tightly in the peptide-binding groove of the MHC molecule. These amino acids are called _____ and the combination of these key residues is known as its _____.alleles; allotypesanchor residues; peptide-binding motifallotype; haplotypesinvariant chains; haplotypesrestriction residues; MHC allotype.

Which of the following is not a characteristic of immunoproteasomes?They make up about 1% of cellular protein.They consist of four rings of seven polypeptide subunits that exist in alternative forms.They are produced in response to IFN-γ produced during innate immune responses.They produce a higher proportion of peptides containing acidic amino acids at the carboxy terminus compared with constitutive proteasomes.They contain 20S proteasome-activation complexes on the caps.

What is the only antibody that can cross the placenta?

What is the name of the proteins on all your cells that help you recognize 'self' from 'non-self'?

Antigen processing involves the breakdown of protein antigens and the subsequent association of peptide fragments on the surface of antigen-presenting cells withimmunoglobulinsT-cell receptorscomplement proteinsMHC class I or class II moleculesCD4.

T cells recognize antigen when the antigenforms a complex with membrane-bound MHC molecules on another host-derived cellis internalized by T cells via phagocytosis and subsequently binds to T-cell receptors in the endoplasmic reticulumis presented on the surface of a B cell on membrane-bound immunoglobulinsforms a complex with membrane-bound MHC molecules on the T cellbears epitopes derived from proteins, carbohydrates, and lipids.

Identify which of the following statements is true regarding the transporter associated with antigen processing (TAP).TAP is a homodimer composed of two identical subunits.TAP transports proteasome-derived peptides from the cytosol directly to the lumen of the Golgi apparatus.TAP is an ATP-dependent, membrane-bound transporter.Peptides transported by TAP bind preferentially to MHC class II molecules.TAP deficiency causes a type of bare lymphocytes syndrome resulting in severely depleted levels of MHC class II molecules on the surface of antigen-presenting cells.

The diversity of MHC class I and II genes is due to _____. (Select all that apply.)gene rearrangements similar to those observed in T-cell receptor genesthe existence of many similar genes encoding MHC molecules in the genomesomatic hypermutationextensive polymorphism at many of the allelesisotype switching.

Which of the following processes occur in both B and T cellsSomatic recombinationSomatic hypermutationIsotype switchingA and BA and C

The combination of all HLA class I and class II allotypes that an individual expresses is referred to as theirhaplotypeallotypeisotypeautotypeHLA type

MHC class II molecules are made up of two chains called _______, whose function is to bind peptides and present them to _______ T cells:alpha (α) and beta (β); CD4alpha (α) and beta2-microglobulin (β2m); CD4alpha (α) and beta (β); CD8alpha (α) and beta2-microglobulin β2m); CD8alpha (α) and beta (β); γ:δ T cells.

Directional selection is best described asall polymorphic alleles preserved in a populationT-cell receptor interaction with peptide:MHC complexes directed to a planar interfacea mechanism in T cells that is analogous to affinity maturation of immunoglobulinsselected alleles increase in frequency in a populationselection of most appropriate transplant donor directed at the identification of identical or similar combinations of HLA alleles compared with the transplant recipient.