Exp Mol Med.  2009 Dec;41(12):866-872. 10.3858/emm.2009.41.12.092.

The presence of CD8+ invariant NKT cells in mice

• Lee H
• Hong C
• Shin J
• Oh S
• Jung S
• Park YK
• Hong S
• Lee GR
• Park SH

• KMID: 1099863
• DOI: http://doi.org/10.3858/emm.2009.41.12.092

Abstract

Invariant natural killer T (iNKT) cells develop in the thymus upon recognition of CD1d expressed on developing thymocytes. Although CD4 and CD8 coreceptors are not directly involved in the interaction between CD1d and the T cell receptors (TCRs) of iNKT cells, a conspicuous lack of CD8+ iNKT cells in mice raised the question of whether CD8+ iNKT cells are excluded due to negative selection during their thymic development, or if there is no lineage commitment for the development of murine CD8+ iNKT cells. To address this question, we analyzed iNKT cell-specific TCR Valpha14+ transgenic mice, where the Valpha14 transgene forces the generation of iNKT cells. This allows detailed study of the iNKT cell repertoire. We were able to identify CD8+ iNKT cells which respond to the NKT cell-specific glycolipid ligand alpha-galactosylceramide. Unlike conventional iNKT cells, CD8+ iNKT cells produce predominantly IFN-gamma but not IL-4 upon antigen stimulation. We also confirmed the presence of CD8+ iNKT cells in wild type mice. Our results suggest that CD8+ NKT cells do exist in mice, although their population size is quite small. Their Th1-skewed phenotype might explain why the population size of this subtype needs to be controlled tightly.

Keyword

antigens, CD1d; CD8-positive T-lymphocytes; alpha-galactosylceramide; mice, transgenic; natural killer T-cells

MeSH Terms

Animals
CD8-Positive T-Lymphocytes/*immunology/metabolism
Galactosylceramides/immunology
Interferon-gamma/immunology
Interleukin-4/immunology
Mice
Mice, Inbred C57BL
Mice, Transgenic
Natural Killer T-Cells/*immunology/metabolism
Receptors, Antigen, T-Cell, alpha-beta/*genetics
Transgenes