The Molecular Aspects of Functional Activity of Macrophage-Activating Factor GcMAF

Abstract

Group-specific component macrophage-activating factor (GcMAF) is the vitamin D3-binding protein (DBP) deglycosylated at Thr420. The protein is believed to exhibit a wide range of therapeutic properties associated with the activation of macrophagal immunity. An original method for GcMAF production, DBP conversion to GcMAF, and the analysis of the activating potency of GcMAF was developed in this study. Data unveiling the molecular causes of macrophage activation were obtained. GcMAF was found to interact with three CLEC10A derivatives having molecular weights of 29 kDa, 63 kDa, and 65 kDa. GcMAF interacts with high-molecular-weight derivatives via Ca2+-dependent receptor engagement. Binding to the 65 kDa or 63 kDa derivative determines the pro- and anti-inflammatory direction of cytokine mRNA expression: 65 kDa—pro-inflammatory (TNF-α, IL-1β) and 63 kDa—anti-inflammatory (TGF-β, IL-10). No Ca2+ ions are required for the interaction with the canonical 29 kDa CLEC10A. Both forms, DBP protein and GcMAF, bind to the 29 kDa CLEC10A. This interaction is characterized by the stochastic mRNA synthesis of the analyzed cytokines. Ex vivo experiments have demonstrated that when there is an excess of GcMAF ligand, CLEC10A forms aggregate, and the mRNA synthesis of analyzed cytokines is inhibited. A schematic diagram of the presumable mechanism of interaction between the CLEC10A derivatives and GcMAF is provided. The principles and elements of standardizing the GcMAF preparation are elaborated.

The Macrophage Activator GcMAF-RF Enhances the Antitumor Effect of Karanahan Technology through Induction of M2–M1 Macrophage Reprogramming

“…To analyze the events occurring in the tumor of experimental animals treated with Karanahan technology solely and in combination with GcMAF-RF [ 11 ], the results of four experimental series reported in [ 1 , 2 ] were used: May 2020 (No. 1), November 2020 (No.…”

“…In our previous studies, we discovered the third vector of Karanahan technology alone and in combination with the macrophage activator GcMAF-RF—activation of antitumor immunity [ 2 , 11 ]. Analysis of a regressing tumor indicated an effect on TAS elements, namely dendritic cells, MDSCs, and T regulatory cells.…”

“…The protocol for obtaining group-specific macrophage activator (GcMAF-RF) is described in detail in [ 1 , 11 ]. GcMAF-RF is the subject of industrial property of “ACTIVATOR MAF” LLC.…”

Identification and Molecular Characterization of the Human GcMAF Receptor<b></b>

“…It is also possible that the interaction observed by Kirikovich et al (2023) might be due to the "sticky" nature of Gc protein, a protein whose function is, among others, to bind actin as an actin scavenger (Otterbein et al 2002). In addition, the mechanism proposed by Kirikovich et al (2023) does not take into consideration the observation by Nabeshima et al (2020) that Gc2 has GcMAF activity despite the absence of GalNAc. However, it is also possible that GcMAF binds different receptors either on the same cell or in different cell types.…”

“…Another recent hypothesis concerning the GcMAF receptor comes from the article by Kirikovich et al (2023) who demonstrated that in a cell-free environment GcMAF can interact with the protein encoded by the CLEC10A gene, a C-type lectin domain family 10 member A that is a single-pass type II membrane protein also known as Macrophage lectin 2. Although these results merit consideration since GalNAc is known to bind to this protein, it is worth noting that Macrophage lectin 2 is not listed among the interactors of human Gc protein and is difficult to envisage a role for this protein in angiogenesis, autism, or neuroprotection, conditions where GcMAF has proven effective.…”