Despite significant advances in neonatal intensive care, including directed antibiotic therapy, mortality from neonatal sepsis remains significant with more than three million deaths worldwide. The highest risk of mortality occurs in preterm, low birth weight (LBW) and very low birth weight (VLBW) neonates. During the initial funding period of this award, we made three novel observations: 1) the neonate relies predominantly on its innate immune system to recognize infections and to provide early protective immunity, 2) host innate immunity is also defective due in part to a failure of innate immune cells to recognize and respond to chemokines essential for recruitment and activation, and 3) adjuvant treatment of mice with TLR and NLR agonists can stimulate PMN function, improve protective immunity, and increase survival to sepsis through MyD88- and inflammasome-independent pathways. Based on these findings, our ultimate goal is to develop adjuvant- therapies based on TLR signaling that can reduce the incidence and severity of both early and late sepsis in LBW/VLBW infants. To accomplish this, there are three specific aims: 1) To delineate the mechanism by which pretreatment of neonates with TRIF-specific pattern recognition receptor (PRRs) agonists improves survival in neonatal sepsis; 2) To determine the mechanisms by which immune adjuvants improve protective immunity and outcomes to neonatal sepsis; and, 3) To determine whether LBW and VLBW infants express comparable defects in PMN chemotaxis, ROS production and bacterial killing seen in PMNs from murine models of neonatal sepsis, and whether treatment of these human cells with TLR4 agonists restores innate immune function. The first two specific aims will determine the mechanisms by which pretreatment of neonatal mice with TRIF-specific TLR4 agonists with and without alum adjuvants improves outcome from E.coli and polymicrobial sepsis. The final specific aim will validate whether the protective effect of TLR agonists and alum seen in neonatal mice are recapitulated in cord and peripheral blood from full-term and LBW/VLBW infants. The ultimate goal of these studies is the reduction of early and late sepsis with improved survival in the highly vulnerable LBW/VLBW infant population by augmenting their immature innate immune system. Ultimately, it is our goal (at the end of this proposed funding period) to move novel or FDA-approved adjuvants and unique TRIF agonists into preliminary clinical trials in LBW/VLBW infants at risk of developing sepsis.

Public Health Relevance

Low and very low birth weight infants have an increased incidence and severity of sepsis due in large part to defective host protective immunity. This proposal investigates the development of novel immune adjuvants based on TLR signaling that can stimulate innate immunity and protect low and very low birth weight infants from early and late sepsis.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
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Special Emphasis Panel (ZRG1)
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Dunsmore, Sarah
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University of Florida
Schools of Medicine
United States
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Rincon, J C; Cuenca, A L; Raymond, S L et al. (2018) Adjuvant pretreatment with alum protects neonatal mice in sepsis through myeloid cell activation. Clin Exp Immunol 191:268-278
Horiguchi, Hiroyuki; Loftus, Tyler J; Hawkins, Russell B et al. (2018) Innate Immunity in the Persistent Inflammation, Immunosuppression, and Catabolism Syndrome and Its Implications for Therapy. Front Immunol 9:595
Raymond, Steven L; Hawkins, Russell B; Murphy, Tyler J et al. (2018) Impact of toll-like receptor 4 stimulation on human neonatal neutrophil spontaneous migration, transcriptomics, and cytokine production. J Mol Med (Berl) 96:673-684
Raymond, Steven L; Rincon, Jaimar C; Wynn, James L et al. (2017) Impact of Early-Life Exposures to Infections, Antibiotics, and Vaccines on Perinatal and Long-term Health and Disease. Front Immunol 8:729
Raymond, Steven L; Holden, David C; Mira, Juan C et al. (2017) Microbial recognition and danger signals in sepsis and trauma. Biochim Biophys Acta Mol Basis Dis 1863:2564-2573
Raymond, Steven L; Stortz, Julie A; Mira, Juan C et al. (2017) Immunological Defects in Neonatal Sepsis and Potential Therapeutic Approaches. Front Pediatr 5:14
Raymond, Steven L; López, María Cecilia; Baker, Henry V et al. (2017) Unique transcriptomic response to sepsis is observed among patients of different age groups. PLoS One 12:e0184159
Stortz, Julie A; Raymond, Steven L; Mira, Juan C et al. (2017) Murine Models of Sepsis and Trauma: Can We Bridge the Gap? ILAR J 58:90-105
Raymond, Steven L; Mathias, Brittany J; Murphy, Tyler J et al. (2017) Neutrophil chemotaxis and transcriptomics in term and preterm neonates. Transl Res 190:4-15
Mathias, Brittany; Mira, Juan C; Rehfuss, Jonathan P et al. (2017) LPS Stimulation of Cord Blood Reveals a Newborn-Specific Neutrophil Transcriptomic Response and Cytokine Production. Shock 47:606-614

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