*Article* **The Comparative Immunotropic Activity of Carrageenan, Chitosan and Their Complexes**

#### **Viktoriya N. Davydova 1,\*,**†**, Irina V. Sorokina 2,**†**, Aleksandra V. Volod'ko 1, Ekaterina V. Sokolova 1, Marina S. Borisova 2 and Irina M. Yermak 1**


Received: 16 July 2020; Accepted: 1 September 2020; Published: 4 September 2020

**Abstract:** The immunotropic activity of polyelectrolyte complexes (PEC) of κ-carrageenan (κ-CGN) and chitosan (CH) of various compositions was assessed in comparison with the initial polysaccharides in comparable doses. For this, two soluble forms of PEC, with an excess of CH (CH:CGN mass ratios of 10:1) and with an excess of CGN (CH: CGN mass ratios of 1:10) were prepared. The ability of PEC to scavenge NO depended on the content of the κ-CGN in the PEC. The ability of the PEC to induce the synthesis of pro-inflammatory (tumor necrosis factorα (TNFα)) and anti-inflammatory (interleukine-10 (IL-10)) cytokines in peripheral blood mononuclear cell was determined by the activity of the initial κ-CGN, regardless of their composition. The anti-inflammatory activity of PEC and the initial compounds was studied using test of histamine-, concanavalin A-, and sheep erythrocyte immunization-induced inflammation in mice. The highest activity of PEC, as well as the initial polysaccharides κ-CGN and CH, was observed in a histamine-induced exudative inflammation, directly related to the activation of phagocytic cells, i.e., macrophages and neutrophils.

**Keywords:** carrageenan; chitosan; polyelectrolyte complex; cytokine; nitric oxide; anti-inflammatory activity
