Analysis of CVC1302-Mediated Enhancement of Monocyte Recruitment in Inducing Immune Responses

TL;DR

The study explores how CVC1302 recruits different monocyte subsets to lymph nodes, enhancing immune responses through antigen presentation and chemokine secretion.

Contribution

The paper identifies distinct roles of Ly6C+ and Ly6C− monocytes in immune response initiation following CVC1302 treatment.

Findings

CVC1302 recruits both Ly6C+ and Ly6C− monocytes to lymph nodes from different origins.

Ly6C− monocytes secrete higher levels of CXCL9 and CXCL10, attracting antigen-specific CD4+ T cells.

Ly6C+ monocytes primarily capture and present antigens, while Ly6C− monocytes secrete chemokines.

Abstract

Monocytes (Mos) are believed to play important roles during the generation of immune response. In our previous study, CVC1302, a complex of PRRs agonists, was demonstrated to recruit Mo into lymph nodes (LNs) in order to present antigen and secret chemokines (CXCL9 and CXCL10), which attracted antigen-specific CD4+ T cells. As it is known that Mos in mice are divided into two main Mo subsets (Ly6C+ Mo and Ly6C− Mo), we aimed to clarify the CVC1302-recruiting Mo subset and functions in the establishment of immunity. In this study, we found that CVC1302 attracted both Ly6C+ Mo and Ly6C− Mo into draining LNs, which infiltrated from different origins, injection muscles and high endothelial venule (HEV), respectively. We also found that the numbers of OVA+ Ly6C+ Mo in the draining LNs were significantly higher compared with OVA+ Ly6C− Mo. However, the levels of CXCL9 and CXCL10 produced by Ly6C− Mo were significantly higher than Ly6C+ Mo, which plays important roles in attracting antigen-specific CD4+ T cells. Under the analysis of their functions in initiating immune responses, we found that the ability of the Ly6C+ monocyte was mainly capturing and presenting antigens, otherwise; the ability of the Ly6C− monocyte was mainly secreting CXCL9 and CXCL10, which attracted antigen-specific CD4+ T cells through CXCR3. These results will provide new insights into the development of new immunopotentiators and vaccines.

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