Class I negative CD8 T cells reveal the confounding role of peptide-transfer onto CD8 T cells stimulated with soluble H2-Kb molecules.
Crosslinking of the T cell receptor has been proposed to be a prerequisite for T cell activation. Although the evidence supports this notion for CD4 T cells, the situation for CD8 T cells is less clear. Soluble class I monomers have been used to determine activation requirements in vitro with contradictory results. The possibility of transfer of peptide from soluble class I molecules onto class I molecules present on the surface of CD8 T cells, with ensuing presentation to other CD8 T cells, has been widely ignored. We show that monomeric and tetrameric class I molecules as well as free peptide can stimulate naive CD8 T cells in vitro. We generate and characterize CD8 T cells that express the OT-I T cell receptor (for K(b)/SIINFEKL) yet lack K(b) and D(b) molecules, and show that their activation requirements differ from their class I positive counterparts when stimulated with soluble K(b) molecules. By eliminating the confounding effect of peptide transfer, we unmask the true activation requirements for naive CD8 T cells and show that multivalent engagement of T cell receptors, as well as costimulation, is required for optimal stimulation.
Schott
Eckart
E
Department of Pathology, Harvard Medical School, Boston, MA 02115, USA.
Bertho
Nicolas
N
Ge
Qing
Q
Maurice
Madelon M
MM
Ploegh
Hidde L
HL
D019264:Adoptive Transfer; D000595:Amino Acid Sequence; D000818:Animals; D017951:Antigen Presentation; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D004527:Egg Proteins / Q000737:chemistry / Q000276:immunology; D006183:H-2 Antigens / Q000737:chemistry / Q000378:metabolism*; D015395:Histocompatibility Antigens Class I / Q000378:metabolism*; D066298:In Vitro Techniques; D008213:Lymphocyte Activation; D051379:Mice; D008822:Mice, Transgenic; D010047:Ovalbumin / Q000737:chemistry / Q000276:immunology; D010446:Peptide Fragments; D010455:Peptides / Q000737:chemistry / Q000276:immunology; D010641:Phenotype; D020836:Protein Structure, Quaternary; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000378:metabolism; D012995:Solubility
D004527:Egg Proteins; D006183:H-2 Antigens; C032876:H-2Kb protein, mouse; D015395:Histocompatibility Antigens Class I; C110366:OVA-8; D010446:Peptide Fragments; D010455:Peptides; D011948:Receptors, Antigen, T-Cell; D010047:Ovalbumin