## 3 Results  
### Immunomodulatory Properties of Phormidium Papyvacuum Extract  
To determine the influence of the _P. papyvacuum_ extract on the immunophenotype and composition of the adaptive immune cells, we designed staining panels that allow us to identify the major subsets of T cells, B cells, antigen-presenting cells (APCs), and NK cells. The expression levels of the main surface markers characterizing the major cell subpopulations were compared between extract-treated and untreated cells (Table 2). No differences between treated and untreated leukocytes were observed for B cells (CD19), plasma cells (CD138), monocytes/macrophages (CD11b), or NK cells (CD16/CD56) (Table 2). To evaluate the T cell subsets in response to the cyanobacterial extract, we analysed the expression of CD3, CD4, CD8, CD25, and CD152. The data demonstrated a strong activation of the CD4\({}^{+}\) T lymphocytes after treatment with _P. papyraceum_ extract with no significant changes of the CD8\({}^{+}\) T cell subpopulation (Table 2). As shown in Figure 2, there was a significant increase in the percentages of activated T cells (CD4\({}^{+}\)CD152\({}^{+}\)) and regulatory T cells (Tregs, CD4\({}^{+}\)CD25\({}^{+}\)) within extract-treated cells compared to untreated cells. No such difference was observed for the CD8\({}^{+}\)CD25\({}^{+}\) population (Figure 3). \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**CD Markers**} & \multirow{2}{*}{**Extract-Treated Cells**} & **Untreated Cells** & **PHA-L Treated Cells** \\  & & **(Negative Control)** & **(Positive Control)** \\ \hline
**CD3 (\%)** & **22.10 \(\pm\) 3.92 a** & 11.91 \(\pm\) 4.47 & **28.30 \(\pm\) 3.13** \\
**CD4 (\%)** & **18.87 \(\pm\) 2.00 a** & 10.57 \(\pm\) 3.5 & **24.37 \(\pm\) 5.42** \\
**CD8 (\%)** & 2.10 \(\pm\) 0.02 & 2.29 \(\pm\) 1.15 & **10.64 \(\pm\) 1.07** \\
**CD25 (\%)** & **5.30 \(\pm\) 1.24 a** & 1.02 \(\pm\) 0.08 & **8.04 \(\pm\) 1.12** \\
**CD152 (\%)** & **15.70 \(\pm\) 2.18 a** & 4.64 \(\pm\) 2.18 & **32.60 \(\pm\) 4.35** \\
**CD19 (\%)** & 3.29 \(\pm\) 0.19 & 4.55 \(\pm\) 0.51 & 3.45 \(\pm\) 0.47 \\
**HLA-DR-DP (\%)** & **11.12 \(\pm\) 1.79 a** & 4.27 \(\pm\) 0.99 & **12.13 \(\pm\) 1.80** \\
**CD11b (\%)** & 1.12 \(\pm\) 0.38 & 1.03 \(\pm\) 0.02 & 1.38 \(\pm\) 0.22 \\
**CD138 (\%)** & 2.62 \(\pm\) 0.39 & 1.42 \(\pm\) 0.09 & 1.88 \(\pm\) 0.19 \\
**CD80 (\%)** & 2.26 \(\pm\) 1.91 & 2.12 \(\pm\) 0.97 & 1.46 \(\pm\) 0.13 \\
**CD16 (\%)** & 1.16 \(\pm\) 0.02 & 1.12 \(\pm\) 0.04 & 1.16 \(\pm\) 0.05 \\
**CD56 (\%)** & 1.45 \(\pm\) 0.90 & 2.79 \(\pm\) 0.29 & **4.27 \(\pm\) 0.56** \\ \hline \hline \end{tabular} For comparison (extract-treated vs. untreated cells), the non-parametric Mann-Whitney \(U\) test was used. Values that are statistically significant vs. control are given in bold. \({}^{\sharp}\)_p_-Value \(<\) 0.001.  
\end{table} 
Table 2: Immunophenotyping of human leukocytes after in vitro treatment with _P. papyraceum_ extract. The cells were stained using 5-color panels of indicated surface markers and analysed by FACS. Percentages \(\pm\) SD (_n_ = 10) of specific populations from the total number of cells are shown. Figure 2: Frequency of some T cell subpopulations after treatment with _P. papyraceum_ extract and without treatment: (**a**) CD3\({}^{+}\)CD4\({}^{+}\)CD152\({}^{+}\) cells; (**b**) CD3\({}^{+}\)CD4\({}^{+}\)CD25\({}^{+}\) cells. Asterisks denote statistically significant differences from the untreated cells (****\(p<\) 0.001) as determined by Mann-Whitney \(U\) test. Data are presented as means \(\pm\) SD (_n_ = 10). The treatment with _P. papyraceum_ extract was able to modulate the levels of some proinflammatory cytokines that are responsible for the cell-mediated immunity and the initial activation of the immune system. Observed activation of the CD4+ T cells by the extract was accompanied with significantly enhanced secretion of IL-2 and IL-6 (2.8 and 2.5-fold), as compared with untreated cells, respectively (Figure 4). In contrast, the secretion of TNF-\(\alpha\) was not affected (Figure 4). Figure 4: _P.