The second life of antibodies

Abstract

Antibodies (immunoglobulins, Ig) are used by the immune system to identify and neutralize foreign objects and are responsible for antigen-binding and effector functions. Immunoglobulin G (IgG) is the major serum immunoglobulin of a healthy human (~75% of the total Ig fraction). The discovery in 1970 of the endogenous tetrapeptide tuftsin (Thr-Lys-Pro-Arg, fragment 289-292 of the C(H2)-domain of the heavy (H) chain of IgG), possessing both immunostimulatory and neurotrophic activities, was an impetus for the search for new biologically active peptides of immunoglobulin origin. As a result, fragments of the H-chain of IgG produced as a result of enzymatic cleavage of IgG within the antigen-antibody complex were discovered, synthesized, and studied. These fragments include rigin (341-344), immunorphin (364-373), immunocortin (11-20), and peptide p24 (335-358) and its fragments. In this review the properties of these peptides and their role in regulating the immune response are analyzed.

Circulating immune complexes and markers of systemic inflammation in RAO-affected horses

“…Circulating immune complexes are protein structures that are formed as a consequence of an immune response of the organism to the antigens of various origin (Navolotskaya 2014). Results of our study indicate the presence of significantly elevated levels of circulating immune complexes in the serum of horses with RAO exacerbation compared with healthy controls.…”

“…Lack of the above mentioned data creates difficulties in assessing and comparing the results with those of other authors. In humans, many insights have been made into the pathogenesis of diseases such as rheumatoid arthritis and glomerulonephritis, using the analysis of the levels of circulating immune complexes levels (Nowak-Łoś et al 2013, Navolotskaya 2014, Wener 2014. The incidence of circulating immune complexes has been ascertained for many disease conditions (Haymen 1990, Pandey 2013, Maheswari et al 2014) and the level of circulating immune complexes has been correlated with the activity of certain diseases.…”

Antibodies as a Source of Anti-Infective Peptides: An Update

“…These peptides can act as signaling molecules mostly involved in the regulation of the immune response. Even though at present there are no data on generation of similar peptides in vivo, it is conceivable that they can future science group www.futuremedicine.com actually be produced under physiological conditions in the body [36]. Proceeding in studies previously carried out on KAbs, since 2003 our group has been involved in selecting peptides derived first from the V region, then from the Fc region of Abs, and in characterizing their antimicrobial, antiviral, immunomodulatory and antitumor activities.…”

Plasmodium falciparum malaria and invasive bacterial co-infection in young African children: the dysfunctional spleen hypothesis

“…Additionally, in the spleen tuftsin is synthetized, an opsonin that activates the alternative complement pathway [6, 17], and that has receptors expressed on monocytes/macrophages, neutrophils and NK cells [64]. Upon binding its receptor, the complex is taken into the phagocyte and initiates the production of superoxide and nitroxide radicals, essential molecules for the killing of phagocytosed bacteria [64].…”

“…Upon binding its receptor, the complex is taken into the phagocyte and initiates the production of superoxide and nitroxide radicals, essential molecules for the killing of phagocytosed bacteria [64]. Therefore, the main outcome of tuftsin binding to macrophages and neutrophils is the stimulation of the ability of these cells to digest that leads to termination of phagocytosis in lymphoid formations [64]. Its importance has been confirmed by the development of fatal infections in splenectomized humans and other animals with lack of tuftsin [64].…”