In periodontal disease and other diseases, resistance to infection is enhanced when neutrophils respond to lipopolysaccharide (LPS) from bacteria and become primed. Priming results in increased ability of neutrophils to produce microbicidal oxygen radicals and enzymes when they phagocytize microbes. However, to limit inflammation and to avoid tissue damage by oxygen radicals and other products of primed neutrophils, the bacteria must be efficiently killed, and their LPS must be rapidly inactivated. The objective of this proposal is to investigate the inactivation of LPS by neutrophils. In preliminary experiments, LPS that had been pre- incubated with neutrophils lost its ability to prime fresh neutrophils. The LPS was not absorbed or destroyed, because its ability to gel Limulus lysate (a standard test for LPS) was not impaired. In preliminary work, a protein of approximately 80 kDa that inactivated LPS was isolated from neutrophil culture supernatant.
Specific Aim 1 is to identify the enzyme or binding factor from neutrophils that inactivates LPS. The LPS inactivating protein will be purified. The purified protein will be characterized and partially sequenced, to see if it is a novel protein.
Specific Aim 2 is to identify any chemical change in LPS that results from inactivation by neutrophils. Inactivated LPS will be purified and chemically characterized by chromatography and mass spectroscopy.
Specific Aim 3 is to identify factors in serum that protect LPS against inactivation. The affinity and concentration of LPS protecting factors in serum will be compared with affinity and concentration of the LPS in activating factor of neutrophils. This might help to clarify the role of serum exudate in potentiating neutrophil-mediated inflammatory responses in tissues.
Specific Aim 4 is to determine the biological activity of inactivated LPS on monocytes. LPS inactivated by neutrophils might be active on monocytes. The ability of monocytes to inactivate LPS will also be examined.
Specific Aim 5 is to determine if LPS's from periodontal pathogens are inactivated normally by neutrophils. LPS from a pathogen might resist inactivation, leading to chronic inflammation and loss of connective tissue and bone. Alternatively, LPS from a pathogen might already exist in a form that appears inactivated to neutrophils. Such LPS might allow a bacterium to avoid priming neutrophils and therefore avoid being efficiently killed by neutrophils. This investigation might lead to stratagems for increasing resistance to infection and decreasing tissue damage in periodontal disease and other chronic infections.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Research Project (R01)
Project #
5R01DE011125-02
Application #
2132249
Study Section
Oral Biology and Medicine Subcommittee 1 (OBM)
Project Start
1994-09-01
Project End
1998-08-31
Budget Start
1995-09-01
Budget End
1996-08-31
Support Year
2
Fiscal Year
1995
Total Cost
Indirect Cost
Name
University of Tennessee Health Science Center
Department
Dentistry
Type
Schools of Dentistry
DUNS #
941884009
City
Memphis
State
TN
Country
United States
Zip Code
38163
Kusumoto, K; Aida, Y; Maeda, K et al. (2001) Cross-linking of beta2 integrins caused diminished responses of neutrophils to priming agents like lipopolysaccharide or tumor necrosis factor-alpha: possible involvement of tyrosine kinase Syk. Microbiol Immunol 45:241-8
Pabst, M J; Beranova-Giorgianni, S; Krueger, J M (1999) Effects of muramyl peptides on macrophages, monokines, and sleep. Neuroimmunomodulation 6:261-83
Nakatomi, K; Aida, Y; Kusumoto, K et al. (1998) Neutrophils responded to immobilized lipopolysaccharide in the absence of lipopolysaccharide-binding protein. J Leukoc Biol 64:177-84
Nakabo, Y; Pabst, M J (1998) Inhibition by sphingosine of leukemic cell killing by human monocytes activated with interleukin-2: a possible role of protein kinase C. Jpn J Cancer Res 89:548-55
Beranova-Giorgianni, S; Desiderio, D M; Pabst, M J (1998) Structures of biologically active muramyl peptides from peptidoglycan of Streptococcus sanguis. J Mass Spectrom 33:1182-91
Nakabo, Y; Pabst, M J (1997) C2-ceramide and C6-ceramide inhibited priming for enhanced release of superoxide in monocytes, but had no effect on the killing of leukaemic cells by monocytes. Immunology 90:477-82
Nakabo, Y; Pabst, M J (1996) Lysis of leukemic cells by human macrophages: inhibition by 4-(2-aminoethyl)-benzenesulfonyl fluoride (AEBSF), a serine protease inhibitor. J Leukoc Biol 60:328-36
Aida, Y; Kusumoto, K; Nakatomi, K et al. (1995) An analogue of lipid A and LPS from Rhodobacter sphaeroides inhibits neutrophil responses to LPS by blocking receptor recognition of LPS and by depleting LPS-binding protein in plasma. J Leukoc Biol 58:675-82
Pabst, M J; Pabst, K M; Collier, J A et al. (1995) Inhibition of neutrophil and monocyte defensive functions by nicotine. J Periodontol 66:1047-55
Wang, D; Pabst, K M; Aida, Y et al. (1995) Lipopolysaccharide-inactivating activity of neutrophils is due to lactoferrin. J Leukoc Biol 57:865-74