A protective role of γδ T cells in primary infection with <em>Listeria monocytogenes</em> in autoimmune non-obese diabetic mice.

We investigated the host defense mechanism in primary infection with Listeria monocytogenes in non-obese diabetic (NOD) mice at pre-diabetic stage showing an impaired responsiveness of the αβ T cells to T-cell receptor (TCR) triggering. The NOD mice showed a deteriorated resistance at the late stage after an intraperitoneal infection with L. monocytogenes compared with BALB/c and C57BL/6 mice as assessed by bacterial growth in organs. Consistent with our previous findings, a prominent increase in number of γδ T cells was evident at the early stage after infection, while generation of Listeria-specific αβ T cells was impaired in these mice. In vivo administration of anti-TCR γδ monoclonal antibody (mAb) allowed L. monocytogenes to grow exaggeratedly in the NOD mice. These results imply that γδ T cells may be mainly involved in protection against primary infection with L. monocytogenes in NOD mice. [ABSTRACT FROM AUTHOR]