). In the present study, the immunogenicity of recombinant RABV expressing MIP-1␣ (rHEP-MIP1␣) was determined. It was found that intramuscular immunization of BALB/c mice with rHEP-MIP1␣ resulted in a higher level of expression of MIP-1␣ at the site of inoculation, increased recruitment of dendritic cells (DCs) and mature B cells into the draining lymph nodes and the peripheral blood, and higher virus-neutralizing antibody titers than immunization with the parent rHEP and recombinant RABVs expressing RANTES (CCL5) or IP-10 (CXCL10). Our data thus demonstrate that expression of MIP-1␣ not only reduces viral pathogenicity but also enhances immunogenicity by recruiting DCs and B cells to the site of immunization, the lymph nodes, and the blood.Rabies continues to present public health problems worldwide and causes more than 55,000 human deaths each year, most of which occur in the developing nations of Asia and Africa, where dog rabies remains the main source of human exposure (8, 31). Current rabies vaccines are made with inactivated rabies virus (RABV) grown in cultured cells. Although these vaccines are safe and efficacious, multiple doses (at least 4) must be administered over an extended period of time (14 days) to stimulate optimal immune responses (24). Furthermore, the high cost of cell culture-based vaccines makes it difficult to utilize them effectively in developing countries where they are needed most (28). A live attenuated RABV vaccine (SAG-2) and a recombinant vaccinia virus expressing RABV glycoprotein (VRG) have been licensed particularly for use in the oral immunization of wild animals (10, 29). These vaccines are effective; however, VRG may cause intense skin inflammation and systemic vaccinia infection (3, 25), and SAG-2 induces a low level of virus-neutralizing antibody (VNA) responses in wild animals (11).Recent studies demonstrated that the activation of innate immune responses is one of the mechanisms by which RABV is attenuated (16, 30). Induced innate-response genes include inflammatory chemokines and cytokines, interferons (IFNs) and IFN-related genes, and Toll-like receptors (14,(22)(23). Furthermore, it was found that overexpression of the chemokine MIP-1␣ (CCL3) in mouse brain further decreased RABV pathogenicity, while overexpression of RANTES (CCL5) or IP-10 (CXCL10) increased RABV pathogenicity (35). In this study, the immunogenicity of the recombinant high egg passage (rHEP) Flury strain of RABV that contains the MIP-1␣ gene (rHEP-MIP1␣) was investigated.To ensure that the decreased pathogenicity of rHEP-MIP1␣, as shown previously (35), is due to the overexpression of MIP-1␣, another rHEP virus was constructed with a MIP-1␣ gene cloned into the rHEP genome that does not express MIP-1␣ protein because two stop codons were introduced near the N terminus of the MIP-1␣ gene, one stop codon (TAG) replacing TCA (residues 68 to 70) and the other replacing the codon ATG (residues 78 to 80). The recombinant RABV was rescued, using the procedures described by Inoue et al. (13), and was de...