Lipid Transfer Proteins As Components of the Plant Innate Immune System: Structure, Functions, and Applications

Among a variety of molecular factors of the plant innate immune system, small proteins that transfer lipids and exhibit a broad spectrum of biological activities are of particular interest. These are lipid transfer proteins (LTPs). LTPs are interesting to researchers for three main features. The first feature is the ability of plant LTPs to bind and transfer lipids, whereby these proteins got their name and were combined into one class. The second feature is that LTPs are defense proteins that are components of plant innate immunity. The third feature is that LTPs constitute one of the most clinically important classes of plant allergens. In this review, we summarize the available data on the plant LTP structure, biological properties, diversity of functions, mechanisms of action, and practical applications, emphasizing their role in plant physiology and their significance in human life.

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Streptococcal Inhibitor of Complement Inhibits Two Additional Components of the Mucosal Innate Immune System: Secretory Leukocyte Proteinase Inhibitor and Lysozyme

Infection and Immunity ◽

10.1128/iai.70.9.4908-4916.2002 ◽

2002 ◽

Vol 70 (9) ◽

pp. 4908-4916 ◽

Cited By ~ 60

Author(s):

Barbara A. Fernie-King ◽

David J. Seilly ◽

Alexandra Davies ◽

Peter J. Lachmann

Keyword(s):

Immune System ◽

Temperature Dependence ◽

Innate Immune System ◽

Proteinase Inhibitor ◽

Biological Activities ◽

Insertion Site ◽

Innate Immune ◽

Strong Temperature Dependence ◽

Secretory Leukocyte Proteinase Inhibitor

ABSTRACT Streptococcal inhibitor of complement (SIC) is a 31-kDa extracellular protein of a few, very virulent, strains of Streptococcus pyogenes (particularly M1 strains). It is secreted in large quantities (about 5 mg/liter) and inhibits complement lysis by blocking the membrane insertion site on C5b67. We describe investigations into the interaction of SIC with three further major components of the innate immune system found in airway surface liquid, namely, secretory leukocyte proteinase inhibitor (SLPI), lysozyme, and lactoferrin. Enzyme-linked immunosorbent assays showed that SIC binds to SLPI and to both human and hen egg lysozyme (HEL) but not to lactoferrin. Studies using 125I-labeled proteins showed that SIC binds approximately two molecules of SLPI and four molecules of lysozyme. SLPI binding shows little temperature dependence and a small positive enthalpy, suggesting that the binding is largely hydrophobic. By contrast, lysozyme binding shows strong temperature dependence and a substantial negative enthalpy, suggesting that the binding is largely ionic. Lysozyme is precipitated from solution by SIC. Further studies examined the ability of SIC to block the biological activities of SLPI and lysozyme. An M1 strain of group A streptococci was killed by SLPI, and the antibacterial activity of this protein was inhibited by SIC. SIC did not inhibit the antiproteinase activity of SLPI, implying that there is specific inhibition of the antibacterial domain. The antibacterial and enzymatic activities of lysozyme were also inhibited by SIC. SIC is the first biological inhibitor of the antibacterial action of SLPI to be described and may prove to be an important tool for investigating this activity in vivo. Inhibition of the antibacterial actions of SLPI and lysozyme would be advantageous to S. pyogenes in establishing colonization on mucosal surfaces, and we propose that this is the principal function of SIC.

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Antimicrobial Peptides from Amphibian Innate Immune System as Potent Antidiabetic Agents: A Literature Review and Bioinformatics Analysis

Journal of Diabetes Research ◽

10.1155/2021/2894722 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Hossein Soltaninejad ◽

Hadi Zare-Zardini ◽

Mahtab Ordooei ◽

Yaser Ghelmani ◽

Akram Ghadiri-Anari ◽

...

Keyword(s):

Immune System ◽

Antimicrobial Peptides ◽

Innate Immune System ◽

Bioinformatics Analysis ◽

Biological Activities ◽

Innate Immune ◽

Antidiabetic Activity ◽

Net Charge ◽

Peptide Family ◽

Negative Side Effects

Antimicrobial peptides, as an important member of the innate immune system, have various biological activities in addition to antimicrobial activity. There are some AMPs with antidiabetic activity, especially those isolated from amphibians. These peptides can induce insulin release via different mechanisms based on peptide type. In this review study, we collected all reported AMPs with antidiabetic activity. We also analyze the sequence and structure of these peptides for evaluation of sequence and structure effect on their antidiabetic activity. Based on this review, the biggest peptide family with antidiabetic activity is temporins with nine antidiabetic peptides. Frogs are the most abundant source of antidiabetic peptides. Bioinformatics analysis showed that an increase of positive net charge and a decrease of hydrophobicity can improve the insulinotropic effect of peptides. Peptides with higher positive net charge and Boman index showed higher activity. Based on this review article, AMPs with antidiabetic activity, especially those isolated from amphibians, can be used as novel antidiabetic drug for type 2 diabetes disease. So, amphibians are potential sources for active peptides which merit further evaluation as novel insulin secretagogues. However, strategy for the increase of stability and positive activity as well as the decrease of negative side effects must be considered.

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Fish Immunology. The modification and manipulation of the innate immune system: Brazilian studies

Anais da Academia Brasileira de Ciências ◽

10.1590/0001-3765201420130159 ◽

2014 ◽

Vol 86 (3) ◽

pp. 1484-1506 ◽

Cited By ~ 26

Author(s):

JAQUELINE D. BILLER-TAKAHASHI ◽

ELISABETH C. URBINATI

Keyword(s):

Immune System ◽

Innate Immune System ◽

New Technologies ◽

Disease Outbreaks ◽

Innate Immune ◽

System Structure ◽

Economic Losses ◽

Massive Growth ◽

And Function ◽

Brazilian Studies

The understanding of fish immune system structure and function is essential for the development of new technologies and products to improve productivity. This is the first review on immune system of fish with Brazilian studies. Aquaculture in Brazil has shown massive growth in recent years due to methods of culture intensification. However, these procedures led to disease outbreaks, as well as the chemotherapy and the misuse of antibiotics. A viable alternative to avoid the use of chemicals and prevent economic losses is the administration of immunostimulants and prebiotcs, which act by increasing the innate immune system. In Brazil there is a lack of studies on fish immune system, except by some groups that have studied the effects of the immunostimulants administration in various species.

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