scholarly journals Antigen Processing in the Endoplasmic Reticulum Is Monitored by Semi-Invariant αβ TCRs Specific for a Conserved Peptide–Qa-1b MHC Class Ib Ligand

2017 ◽  
Vol 198 (5) ◽  
pp. 2017-2027 ◽  
Author(s):  
Jian Guan ◽  
Soo Jung Yang ◽  
Federico Gonzalez ◽  
Yuxin Yin ◽  
Nilabh Shastri
Keyword(s):  
Endoplasmic Reticulum ◽  
Antigen Processing ◽  
Mhc Class Ib ◽  
Class Ib

scholarly journals Nonclassical MHC class Ib–restricted cytotoxic T cells monitor antigen processing in the endoplasmic reticulum

2012 ◽  
Vol 13 (6) ◽  
pp. 579-586 ◽  
Author(s):  
Niranjana A Nagarajan ◽  
Federico Gonzalez ◽  
Nilabh Shastri
Keyword(s):  
T Cells ◽  
Endoplasmic Reticulum ◽  
Antigen Processing ◽  
Cytotoxic T Cells ◽  
Mhc Class Ib ◽  
Nonclassical Mhc ◽  
Class Ib

scholarly journals The Selection of M3-Restricted T Cells Is Dependent on M3 Expression and Presentation of N-Formylated Peptides in the Thymus

1999 ◽  
Vol 190 (12) ◽  
pp. 1869-1878 ◽  
Author(s):  
Nancy M. Chiu ◽  
Bin Wang ◽  
Kristen M. Kerksiek ◽  
Roger Kurlander ◽  
Eric G. Pamer ◽  
...  
Keyword(s):  
T Cells ◽  
Negative Selection ◽  
Antigen Processing ◽  
Partial Agonist ◽  
Mhc Class Ib ◽  
Histocompatibility Complex ◽  
Fetal Thymic Organ Culture ◽  
Single Positive ◽  
Class Ib

The major histocompatibility complex (MHC) class Ib molecule H2-M3 binds N-formylated peptides from mitochondria and bacteria. To explore the role of M3 expression and peptide supply in positive and negative selection, we generated transgenic mice expressing an M3-restricted TCR-α/β from a CD8+ T cell hybridoma (D7) specific for a listerial peptide (LemA). Development of M3-restricted transgenic T cells is impaired in both β2-microglobulin–deficient and transporter associated with antigen processing (TAP)-deficient mice, but is not diminished by changes in the H-2 haplotype. Maturation of M3/LemA-specific CD8+ single positive cells in fetal thymic organ culture was sensitive to M3 expression levels as determined by antibody blocking and use of the castaneus mutant allele of M3. Positive selection was rescued in TAP−/− lobes by nonagonist mitochondrial and bacterial peptides, whereas LemA and a partial agonist variant caused negative selection. Thus, M3-restricted CD8+ T cells are positively and negatively selected by M3, with no contribution from the more abundant class Ia molecules. These results demonstrate that class Ib molecules can function in thymic education like class Ia molecules, despite limited ligand diversity and low levels of expression.

scholarly journals Transporters Associated with Antigen Processing (TAP)-independent Presentation of Soluble Insulin to α/β T Cells by the Class Ib Gene Product, Qa-1b

1998 ◽  
Vol 188 (5) ◽  
pp. 961-971 ◽  
Author(s):  
S. Mark Tompkins ◽  
Jennifer R. Kraft ◽  
Chinh T. Dao ◽  
Mark J. Soloski ◽  
Peter E. Jensen
Keyword(s):  
T Cells ◽  
Mhc Class Ii ◽  
Antigen Processing ◽  
Mhc Class Ib ◽  
Histocompatibility Complex ◽  
Soluble Insulin ◽  
Restriction Element ◽  
Antigen Presenting ◽  
Different Tissues ◽  
Class Ib

T cell hybridomas isolated from nonresponder H-2b mice immunized with pork insulin were stimulated by insulin in the presence of major histocompatibility complex (MHC)-unmatched antigen presenting cells. The restriction element used by these CD4− T cells was mapped to an oligomorphic MHC class Ib protein encoded in the T region and identified as Qa-1b using transfectants. The antigenic determinant was localized to the insulin B chain, and experiments with truncated peptides suggested that it is unexpectedly long, comprising most or all of the 30 amino acid B chain. The antigen processing pathway used to present insulin to the Qa-1b– restricted T cells does not require transporters associated with antigen processing (TAP), and it is inhibited by chloroquine. A wide variety of cell lines from different tissues efficiently present soluble insulin to Qa-1b–restricted T cells, and insulin presentation is not enhanced by phagocytic stimuli. Our results demonstrate that Qa-1b can function to present exogenous protein to T cells in a manner similar to MHC class II molecules. Therefore, this class Ib protein may have access to a novel antigen processing pathway that is not available to class Ia molecules.

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