Homing Studies on Distribution of Ectromelia (Mousepox) Virus-Specific T Cells Adoptively Transferred into Syngeneic H-2 d Mice: Paradigm of Lymphocyte Migration

Mousepox (infectious ectromelia) may be used as a model for studies on the cellular immune response and pathogenesis of generalized viral infections. Ectromelia virus (EV) initially replicates in the footpad (fp) skin at the site of infection, next in draining lymph nodes, and then in the spleen and liver where the virus may induce extensive necrotic process with inflammatory reaction. We show in this study that after recipient BALB/c mice (H-2^d) fp infection with EV prior to the adoptive transfer of syngeneic donor EV-specific cytotoxic T lymphocytes interferon-γ-positive (IFN-γ-⁺), interleukin-2-positive (IL-2⁺), and IL-4⁺ of both phenotypes, CD8⁺ ≈ 70%, and CD4⁺ ≈ 30%) preferentially migrated to the inguinal and auxiliary lymph nodes, spleen, liver, and skin at the site of infection (fp). Many particles of EV with the morphology characteristic for orthopoxviruses and virus-specific immunofluorescence within the cells of inguinal and auxiliary lymph nodes, liver, spleen, and skin have been observed using high-resolution transmission electron microscopy and fluorescence antibody technique, respectively. Results presented in this article support the concept that immune T cells adoptively transferred into infected recipient mice are able not only to specific migration in the host and homing in the sites of virus replication, but also to develop immunoprotection in the transferred animals.