Escherichia coli infection induces only fetal thymus-derived gamma delta T cells at the infected site.
Intraperitoneal infection of mice with Escherichia coli induced activated TCR gamma delta T cells in the peritoneal cavity. We provide evidence that the E. coli-induced gamma delta T cells are derived only from the fetal thymus on the following grounds. The gamma delta T cells were not induced in athymic nude mice and irradiated bone marrow-transferred mice which lack fetal thymus-derived T cells. However, E. coli infection of fetal thymus-grafted nude mice did induce fetal thymus-derived gamma delta T cells. These results suggest that the fetal thymus-derived gamma delta T cells colonize the periphery during early ontogeny, and are maintained until adult age. The E. coli-induced gamma delta T cells express only the Vdelta1 gene. Vgamma6 was predominantly expressed whereas anti-Vgamma1 and anti-Vgamma4 monoclonal antibodies stained less than 3 % of the cells. Direct sequencing of PCR products revealed that Vgamma6 and Vdelta1 genes expressed by the E. coli-induced gamma delta T cells were invariant sequences identical to those expressed in the fetal thymus. The antigen (Ag) specificity of a T cell hybridoma expressing the fetal type Vgamma6 / Vdelta1(+) TCR could not be identified as the cells failed to respond to lipopolysaccharide, E. coli Ag, mycobacterial heat shock protein 65, or isopentenyl pyrophosphate. These results suggest that the Vgamma6 / Vdelta1(+) gamma delta T cells derived from fetal thymus can participate in immune responses against bacterial infection through recognition of a novel class of Ag which is not yet identified.
Matsuzaki
G
G
Department of Immunology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan. matsuzak@biorek.kyushu-u.ac.jp
Takada
H
H
Nomoto
K
K
D000818:Animals; D019070:Cell Lineage / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D004926:Escherichia coli / Q000276:immunology*; D004927:Escherichia coli Infections / Q000276:immunology*; D005803:Genes, Immunoglobulin; D051379:Mice; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000235:genetics / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*; D013950:Thymus Gland / Q000196:embryology / Q000276:immunology*
D016692:Receptors, Antigen, T-Cell, gamma-delta