Use of Cholera Toxin B as a Vaccine Adjuvant Activates Antigen Presenting Cells and Stimulates Production of Pro-Inflammatory Cytokines

<p><em>Francisella tularensis</em> is an intracellular pathogen that has been classified as a category “A” bioterrorism agent by the Centers For Disease Control. To date, there is no approved vaccine to provide protection against this pathogen. Previous <em>in vivo </em>studies with mice<em> </em>have shown that a mucosally targeted vaccine preparation of inactivated <em>F. tularensis</em> (<em>iFt</em>) adjuvanted with Cholera toxin “B” (CTB), successfully granted full protection against a less virulent strain (<em>FT LVS</em>) of the bacterium and provided partial protection against a more virulent strain (SchuS4). However, the mechanisms of this protection are not fully understood. In this present study, an <em>in vitro</em> system was utilized to further elucidate the mechanisms that drive protection against lethal F. tularensis challenge in <em>iFt+CTB </em>mucosally immunized mice. Specifically, the focus was directed towards determining the effects of <em>iFt+CTB </em>on macrophages, the common host of <em>F. tularensis</em>, and their ability to present antigen to naïve T-cells, express costimulatory molecules, and produce pro-inflammatory cytokines. We found that RAW264.7 cells, a murine macrophage cell line, responded to treatment with <em>iFt+CTB</em> by an increased secretion of the pro-inflammatory cytokines IL-6 and TNF-α. It was also determined that treatment with <em>iFt+CTB</em> up-regulated the expression of TLR4 on the macrophage cell surface. The effects of <em>iFt+CTB</em> treatment were shown to increase the expression of both costimulatory molecules B7.1 and B7.2 on the macrophage cell surface. Furthermore, we found that <em>iFt+CTB</em> enhanced the ability of macrophages to present antigen to a <em>FT-specific</em> T-cell hybridoma cell line. These findings allow us to elucidate in part, the mechanisms of protection against <em>F. tularensis </em>challenge in <em>iFt+CTB</em> immunized mice.</p>

Name thesis:degree_name

MS Microbiology

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Biology

Year dc:date.available

2014

Author dc:creator

• Romlein, Heather C.

Contributors dc:contributor

• Constantine Bitsaktsis
• Daniel B. Nichols
• Allan D. Blake
• Jane L. Ko

• cytokines
• Cholera Toxin
• adjuvant
• CTB
• Biology
• Immunity
• Immunoprophylaxis and Therapy
• Microbiology
• Pathogenic Microbiology

Repository record dc:identifier

https://scholarship.shu.edu/dissertations/1997

OAI identifier oai:identifier

oai:scholarship.shu.edu:dissertations-3007