| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
ík*
Laboratories of
*
Viral Diseases and
Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892; and
Section of Immunobiology, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510
To study the requirements for assembly of MHC class I molecules with antigenic peptides in the endoplasmic reticulum (ER), we studied Ag processing in insect cells. Insects lack a class I recognition system, and their cells therefore provide a "blank slate" for identifying the proteins that have evolved to facilitate assembly of class I molecules in vertebrate cells. H-2Kb heavy chain, mouse ß2-microglobulin, and an ER-targeted version of a peptide corresponding to Ova257–264 were expressed in insect cells using recombinant vaccinia viruses. Cell surface expression of Kb-OVA257–264 complexes was quantitated using a recently described complex-specific mAb (25-D1.16). Relative to TAP-deficient human cells, insect cells expressed comparable levels of native, peptide-receptive cell surface Kb molecules, but generated cell surface Kb-OVA257–264 complexes at least 20-fold less efficiently from ER-targeted peptides. The inefficient assembly of Kb-OVA257–264 complexes in the ER of insect cells cannot be attributed solely to a requirement for human tapasin, since first, human cells lacking tapasin expressed endogenously synthesized Kb-OVA257–264 complexes at levels comparable to tapasin-expressing cells, and second, vaccinia virus-mediated expression of human tapasin in insect cells did not detectably enhance the expression of Kb-OVA257–264 complexes. The assembly of Kb-OVA257–264 complexes could be greatly enhanced in insect but not human cells by a nonproteasomal protease inhibitor. These findings indicate that insect cells lack one or more factors required for the efficient assembly of class I-peptide complexes in vertebrate cells and are consistent with the idea that the missing component acts to protect antigenic peptides or their immediate precursors from degradation.
This article has been cited by other articles:
|
|
 |
|
  P. Berglund, D. Finzi, J. R. Bennink, and J. W. Yewdell Viral Alteration of Cellular Translational Machinery Increases Defective Ribosomal Products J. Virol., July 1, 2007; 81(13): 7220 - 7229. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Lopez-Albaitero, J. V. Nayak, T. Ogino, A. Machandia, W. Gooding, A. B. DeLeo, S. Ferrone, and R. L. Ferris Role of Antigen-Processing Machinery in the In Vitro Resistance of Squamous Cell Carcinoma of the Head and Neck Cells to Recognition by CTL J. Immunol., March 15, 2006; 176(6): 3402 - 3409. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. J. Barnden, A. W. Purcell, J. J. Gorman, and J. McCluskey Tapasin-Mediated Retention and Optimization of Peptide Ligands During the Assembly of Class I Molecules J. Immunol., July 1, 2000; 165(1): 322 - 330. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. A. Peh, N. Laham, S. R. Burrows, Y. Zhu, and J. McCluskey Distinct Functions of Tapasin Revealed by Polymorphism in MHC Class I Peptide Loading J. Immunol., January 1, 2000; 164(1): 292 - 299. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R.-C. Su, S. K.-P. Kung, E. T. Silver, S. Lemieux, K. P. Kane, and R. G. Miller Ly-49CB6 NK Inhibitory Receptor Recognizes Peptide-Receptive H-2Kb 1 J. Immunol., November 15, 1999; 163(10): 5319 - 5330. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. Lauvau, B. Gubler, H. Cohen, S. Daniel, S. Caillat-Zucman, and P. M. van Endert Tapasin Enhances Assembly of Transporters Associated with Antigen Processing-dependent and -independent Peptides with HLA-A2 and HLA-B27 Expressed in Insect Cells J. Biol. Chem., October 29, 1999; 274(44): 31349 - 31358. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
