| First Author | Ganta RR | Year | 2004 |
| Journal | Infect Immun | Volume | 72 |
| Issue | 1 | Pages | 159-67 |
| PubMed ID | 14688093 | Mgi Jnum | J:87828 |
| Mgi Id | MGI:3028295 | Doi | 10.1128/IAI.72.1.159-167.2004 |
| Citation | Ganta RR, et al. (2004) Delayed clearance of Ehrlichia chaffeensis infection in CD4+ T-cell knockout mice. Infect Immun 72(1):159-67 |
| abstractText | Human monocytic ehrlichiosis is an emerging tick-borne disease caused by the rickettsia Ehrlichia chaffeensis. To examine the role of helper T cells in host resistance to this macrophage-tropic bacterium, we assessed E. chaffeensis infections in three mouse strains with differing functional levels of helper T cells. Wild-type, C57BL/6J mice resolved infections in approximately 2 weeks. Major histocompatibility complex class II (MHCII) knockout, B6.129-Abb(tm1) mice lacking helper T cells developed persistent infections that were not resolved even after several months. CD4+ T-cell-deficient, B6.129S6-Cd4(tm1Knw) mice cleared the infection, but the clearance took 2 weeks longer than it did for wild-type mice. C57BL/6J mice resolved infection more rapidly following a second experimental challenge, but B6.129S6-Cd4(tm1Knw) mice did not. The B6.129S6-Cd4(tm1Knw) mice also developed active E. chaffeensis-specific immunoglobulin G responses that were slightly lower in concentration and slower to develop than that observed in C57BL/6J mice. E. chaffeensis-specific cytotoxic T cells were not detected following a single bacterial challenge in any mouse strain, including wild-type C57BL/6J mice. However, the cytotoxic T-cell activity developed in all three mouse strains, including the MHCII and CD4+ T-cell knockouts, when challenged with a second E. chaffeensis infection. The data reported here suggest that the cell-mediated immunity, orchestrated by CD4+ T cells is critical for conferring rapid clearance of E. chaffeensis. |
