Acute but not chronic macrophage recruitment in filarial infections in mice is dependent on C‐C chemokine ligand 2

Abstract

Macrophages play an important role in the formation of granulomas and the clearance of Brugia pahangi infections in mice. However, the factors responsible for the recruitment of these cells to the site of infection are not known. In this study we examined the role of the C-C chemokine ligand 2 (CCL2; also known as macrophage chemotactic factor - MCP1) in macrophage recruitment in intraperitoneal infections with B. pahangi. We observed that CCL2 was expressed by peritoneal exudate cells and was present in the sera of wild-type mice. Serum levels of CCL2 peaked twice during the immune response, once during the early, acute phase and again during the late, chronic phase. To further elucidate the role of this chemokine in the anti-filarial immune response, we compared CCL2 deficient (CCL2(-/-)) mice to wild-type mice. We observed that macrophage recruitment was impaired only during the acute phase in the former. While macrophage recruitment was unaffected during the chronic phase, increased accumulation of B and T lymphocytes was seen in these mice. We further report that larval clearance and the in vitro adhesion of PECs to larvae were unimpaired in these mice.

Ly6Chi Monocyte Recruitment Is Responsible for Th2 Associated Host-Protective Macrophage Accumulation in Liver Inflammation due to Schistosomiasis

“…Taking all of the findings together, it is clear that schistosome eggs induce CCL2 production and that CCR2/CCL2 play a role in monocyte recruitment during egg induced inflammation, and that monocytes recruited in this way are contributing to the expansion of the macrophage population at these sites. This is consistent with a role for CCL2 in increased macrophage numbers at sites of infections with other helminths [32], and with microbial pathogens [33], [34]. Monocytes can differentiate into macrophages in response to M-CSF [21] and into dendritic cells in response to GM-CSF [2], [35].…”

Immunogenicity and Protective Efficacy of Brugia malayi Heavy Chain Myosin as Homologous DNA, Protein and Heterologous DNA/Protein Prime Boost Vaccine in Rodent Model

“…Neutrophils showed an increase especially after larval challenge suggesting their effective involvement in killing of larval parasites and indicated a complex interaction of these cells at the site of infection. Earlier reports also indicate that various cell population of peritoneum play a vital role in parasite killing and rapid accumulation of B cells and T cells is crucial to increase the number of macrophages and other cells that might have significant functional implications in the defense against Brugia infections [ 55 – 56 ]. There was only a marginal increase in the percentage of eosinophils in immunized mice post-L3 challenge in contrast to L3 infected control animals which demonstrated considerably increased infiltration of eosinophils suggesting that these cells are possibly not required for killing of the larvae in the adaptive immune response.…”