In the present study, we evaluated the role of CCR2 in a model of viral-induced neurologic disease. An orchestrated expression of chemokines, including the CCR2 ligands monocyte chemoattractant protein-1/CCL2 and monocyte chemoattractant protein-3/CCL7, occurs within the CNS following infection with mouse hepatitis virus (MHV). Infection of mice lacking CCR2 (CCR2−/−) with MHV resulted in increased mortality and enhanced viral recovery from the brain that correlated with reduced (p ≤ 0.04) T cell and macrophage/microglial (determined by F4/80 Ag expression, p ≤ 0.004) infiltration into the CNS. Moreover, MHV-infected CCR2−/− mice displayed a significant decrease in Th1-associated factors IFN-γ (p ≤ 0.001) and RANTES/CCL5 (p ≤ 0.002) within the CNS as compared with CCR2+/+ mice. Further, peripheral CD4+ and CD8+ T cells from immunized CCR2−/− mice displayed a marked reduction in IFN-γ production in response to viral Ag and did not migrate into the CNS of MHV-infected recombination-activating gene (RAG)1−/− mice following adoptive transfer. In addition, macrophage/microglial infiltration into the CNS of RAG1−/− mice receiving CCR2−/− splenocytes was reduced (p ≤ 0.05), which correlated with a reduction in the severity of demyelination (p ≤ 0.001) as compared with RAG1−/− mice receiving splenocytes from CCR2+/+ mice. Collectively, these results indicate an important role for CCR2 in host defense and disease by regulating leukocyte activation and trafficking.
The CC chemokine ligand 2 (CCL2, monocyte chemoattractant protein-1) is important in coordinating the immune response following microbial infection by regulating T cell polarization as well as leukocyte migration and accumulation within infected tissues. The present study examines the consequences of mouse hepatitis virus (MHV) infection in mice lacking CCL2 (CCL2(-/-)) in order to determine if signaling by this chemokine is relevant in host defense. Intracerebral infection of CCL2(-/-) mice with MHV did not result in increased morbidity or mortality as compared to either wild type or CCR2(-/-) mice and CCL2(-/-) mice cleared replicating virus from the brain. In contrast, CCR2(-/-) mice displayed an impaired ability to clear virus from the brain that was accompanied by a reduction in the numbers of antigen-specific T cells as compared to both CCL2(-/-) and wild-type mice. The paucity in T cell accumulation within the central nervous system (CNS) of MHV-infected CCR2(-/-) mice was not the result of either a deficiency in antigen-presenting cell (APC) accumulation within draining cervical lymph nodes (CLN) or the generation of virus-specific T cells within this compartment. A similar reduction in macrophage infiltration into the CNS was observed in both CCL2(-/-) and CCR2(-/-) mice when compared to wild-type mice, indicating that both CCL2 and CC chemokine receptor 2 (CCR2) contribute to macrophage migration and accumulation within the CNS following MHV infection. Together, these data demonstrate that CCR2, but not CCL2, is important in host defense following viral infection of the CNS, and CCR2 ligand(s), other than CCL2, participates in generating a protective response.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.