(1→3)(1→6)-Beta-D-Glucan (High Molecular Weight)

High-MW beta-glucans (100,000-200,000 Da) with (1→3) backbone and (1→6) side branches bind to complement receptor type 3 (CR3/CD11b/CD18) on macrophages and natural killer cells following C3 complement opsonization. This triggers NF-κB activation, TNF-α, IL-8, IL-1β, and IL-12 production, promoting Th1 immune response. Macrophage-produced IL-12 activates CD4+ T-cells and enhances CD8+ cytotoxic T-cell killing. Beta-glucan activity is strictly size-dependent — fragments below 100,000 Da are immunologically inactive, and (1→3) side branching is essential for receptor recognition.