There is evidence suggesting that anti-idiotypic regulation against T cells plays a role in maintaining homeostasis in the immune system,although its mechanism is not fully understood. By using DNA constructs encoding the TCR Vα5.2 and Vβ2.1 chains derived from an ovalbumin(OVA) -specific T cell clone(OVA-T) ,we herein demonstrated that vaccination with TCR-DNA effectively induced anti-idiotypic cellular as well as humoral responses. Serum samples from the TCR-DNA-vaccinated BALB/c mice were able to stain T cells in an idiotype-specific manner. CD4+ T cells from the TCR-DNA-vaccinated mice proliferated in response to stimulation with irradiated syngeneic OVA-T cells and secreted interferon-γ but very little IL-4. Splenocytes from the TCR-DNA-vaccinated mice showed strong idiotype-specific CTL activity against the OVA-T cells. Furthermore,adoptive transfer of the CD4+ or CD8+ T cells from the TCR-DNA-vaccinated mice resulted in hyporesponsiveness of syngeneic recipients. These results demonstrated that vaccination with DNA encoding TCR can effectively activate anti-idiotypic regulatory responses in vivo and thus providing a useful way for immunological intervention. There is evidence suggesting that anti-idiotypic regulation against T cells plays a role in maintaining homeostasis in the immune system, although its mechanism is not fully understood. By using DNA constructs encoding the TCR Vα 5.2 and Vβ 2.1 chains derived from an ovalbumin (OVA) -specific T cell clone (OVA-T), which weve demonstrated that vaccination with TCR-DNA efficiently induced anti-idiotypic cellular as well as humoral responses. Serum samples from the TCR-DNA-vaccinated BALB / c mice were to stain T cells in an idiotype-specific manner. CD4 + T cells from the TCR-DNA-vaccinated mice proliferated in response to stimulation with irradiated syngeneic OVA-T cells and secreted interferon-gamma but very little IL-4. Splenocytes from the TCR -DNA-vaccinated mice showed strong idiotype-specific CTL activity against the OVA-T cells. Furthermore, adoptive transfer of the CD4 + or CD8 + T cells from the TCR-DNA-vaccinated mice resulted in hyporesponsiveness of syngeneic recipients. These result s demonstrated that vaccination with DNA encoding TCR can effectively activate anti-idiotypic regulatory responses in vivo and thus providing a useful way for immunological intervention.