Immunomodulatory and Allergenic Properties of Antimicrobial Peptides

Abstract

With the growing problem of the emergence of antibiotic-resistant bacteria, the search for alternative ways to combat bacterial infections is extremely urgent. While analyzing the effect of antimicrobial peptides (AMPs) on immunocompetent cells, their effect on all parts of the immune system, and on humoral and cellular immunity, is revealed. AMPs have direct effects on neutrophils, monocytes, dendritic cells, T-lymphocytes, and mast cells, participating in innate immunity. They act on B-lymphocytes indirectly, enhancing the induction of antigen-specific immunity, which ultimately leads to the activation of adaptive immunity. The adjuvant activity of AMPs in relation to bacterial and viral antigens was the reason for their inclusion in vaccines and made it possible to formulate the concept of a “defensin vaccine” as an innovative basis for constructing vaccines. The immunomodulatory function of AMPs involves their influence on cells in the nearest microenvironment, recruitment and activation of other cells, supporting the response to pathogenic microorganisms and completing the inflammatory process, thus exhibiting a systemic effect. For the successful use of AMPs in medical practice, it is necessary to study their immunomodulatory activity in detail, taking into account their pleiotropy. The degree of maturity of the immune system and microenvironment can contribute to the prevention of complications and increase the effectiveness of therapy, since AMPs can suppress inflammation in some circumstances, but aggravate the response and damage of organism in others. It should also be taken into account that the real functions of one or another AMP depend on the types of total regulatory effects on the target cell, and not only on properties of an individual peptide. A wide spectrum of biological activity, including direct effects on pathogens, inactivation of bacterial toxins and influence on immunocompetent cells, has attracted the attention of researchers, however, the cytostatic activity of AMPs against normal cells, as well as their allergenic properties and low stability to host proteases, are serious limitations for the medical use of AMPs. In this connection, the tasks of searching for compounds that selectively affect the target and development of an appropriate method of application become critically important. The scope of this review is to summarize the current concepts and newest advances in research of the immunomodulatory activity of natural and synthetic AMPs, and to examine the prospects and limitations of their medical use.

Multifunctional Role of S100 Protein Family in the Immune System: An Update

“…It facilitates the immune response cascade through direct participation, and provides host defense mechanisms by triggering immunological responses against numerous invasion pathogens. Notably, antimicrobial peptides and/or proteins (AMPs) play an essential role in the first line of defense against a wide range of pathogens [ 55 ]. In humans, there are many antimicrobial peptides (AMPs), bactericidal factors, and host defense peptides (HDPs), including RNase7 [ 56 ], Reg3 [ 57 ], α- and β-defensins [ 58 ], S100A7 (psoriasin) [ 59 , 60 ], S100A15 [ 61 ], the S100A8/A9 heterodimer (calprotectin) [ 6 ], and Cathelicidin/hCAP-18 (cleaved into LL-37 and FALL-39) [ 62 , 63 , 64 , 65 ].…”

How Do Pollen Allergens Sensitize?

“…Defensins are small peptides with a pronounced antimicrobial activity which are present in various organs and play an important role in plant defense from phytopathogens. Some pollen defensins may act as allergens ( Guryanova and Ovchinnikova, 2022 ). Defensin-like proteins containing an additional C-terminal domain enriched by hydroxylated and O-glycated proline residues are present in plant pollen and possess allergenic properties ( Finkina and Ovchinnikova, 2018 ).…”

High Level Expression and Purification of Cecropin-like Antimicrobial Peptides in Escherichia coli

“…Recent progress of AMPs conjugated with antibiotics also demonstrated an enhanced killing effect on drug-resistant bacterial strains [ 11 , 12 ]. Moreover, many AMPs possess lipopolysaccharide (LPS) neutralization as well as anticancer activities [ 13 , 14 , 15 ]. Recent studies also summarized the immunomodulatory activities of AMPs in medical uses [ 15 ].…”

“…Moreover, many AMPs possess lipopolysaccharide (LPS) neutralization as well as anticancer activities [ 13 , 14 , 15 ]. Recent studies also summarized the immunomodulatory activities of AMPs in medical uses [ 15 ].…”