Chemokine-Adjuvanted Plasmid DNA Induces Homing of Antigen-Specific and Non-Antigen-Specific B and T Cells to the Intestinal and Genital Mucosae.

Yoann Aldon,Sven Kratochvil,Paul F Mckay,Robin J Shattock

doi:10.4049/jimmunol.1901184

Yoann Aldon, Sven Kratochvil + Show 2 more

Open Access

https://doi.org/10.4049/jimmunol.1901184

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Abstract

Plasmid DNA is a promising vaccine platform that together with electroporation can elicit significant systemic Ab responses; however, immunity at mucosal sites remains low. In this study, we sought to program T and B cells to home to the gastrointestinal and vaginal mucosae using genetic chemokine adjuvants and assessed their impact on immune homeostasis in various distinct immune compartments. BALB/c mice were immunized i.m. with plasmid DNA encoding a model Ag HIV-1 Env gp140 and selected chemokines/cytokine and boosted intravaginally with gp140 recombinant protein. Isolated splenocytes, intestinal lymphocytes, and genital lymphocytes as well as serum and intestinal luminal contents were assessed for Ag-specific reactivity. In addition, flow cytometric analysis was performed to determine the impact on immune homeostasis at these sites. Different molecular chemokine/cytokine adjuvants effected significant alterations to the recruitment of B and T cells to the spleen, vaginal and intestinal mucosae, for example CCL25 enhanced splenic and vaginal Ag-specific T cell responses whereas CCL28 increased the levels of specific T cells only in the vaginal mucosa. The levels of Ab could be modulated in the systemic circulation, as well as the vaginal vault and intestinal lumen, with CCL20 playing a central role. Our data demonstrate that the CCL20, CCL25, and CCL28 genetic chemokine adjuvants enhance the vaccine Ag-specific humoral and cellular responses and induce homing to the intestinal and female genital mucosae.

Highlights

We selected this configuration for our study and further cloned the genes coding for CCL25, CCL27, CCL28, TNF-a, and a scb control gene into the Ag–internal ribosome entry site (IRES)–chemokine backbone
Eliciting an appropriate immune response at mucosal sites is likely necessary to protect from sexually transmitted pathogens such as HIV and Chlamydia, respiratory pathogens like influenza and RSV, or gastrointestinal infections caused by rotavirus, clostridium, and Salmonella
We evaluated the potential of four chemokines (CCL20, CCL25, CCL27, CCL28) and one cytokine (TNF-a) to program T and B cells to home to the female genital tract and/or to the intestinal mucosa upon systemic DNA immunization and a subsequent vaginal protein boost in mice

Summary

Introduction

CN54gp140 soluble Env Ag, we evaluated the potential of the selected chemokines/cytokine to induce homing of Ag-specific immune cells to the intestinal and vaginal mucosae in a DNA prime-protein boost strategy. Among the genetically adjuvanted groups, the Ag–IRES–CCL25 induced the highest Ag-specific serum IgG boosting between week 9 and 10.5 with a ∼ 6.7-fold increase whereas Ag–IRES– CCL27, –CCL28, and –TNF-a were below 3 (Supplemental Fig. 2A).

Results

Conclusion