Laminarin Promotes Immune Responses and Reduces Lactate Dehydrogenase But Increases Glutamic Pyruvic Transaminase in Normal Mice In Vivo.

Laminarin, a typical component of fungal cell walls, has been shown to induce immune responses in both adult and larval locusts. We investigated the effects of laminarin on immune response and glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT) and lactate dehydrogenase (LDH) levels in normal mice.

Thirty-six normal BALB/c mice were randomly divided into four groups and treatments were provided by gavage. Group I mice acted as normal control; mice of groups II-IV received laminarin at different doses (100 μl at 1, 2.5 and 5.0 mg/mouse in double-distilled water, respectively). All animals were treated for 14 days and were weighed, blood was collected for determination of cell markers, liver and spleen samples were weighed. Spleens were used for phagocytosis and determination of natural killer (NK) cell activity and cell proliferation by flow cytometric assay.

Laminarin reduced the body weights and weights of liver and spleen. Laminarin increased CD3, CD19 and Mac-3 cell populations at 2.5 and 5 mg/mouse, however, these did not affect CD11b marker levels. Laminarin (1 and 5 mg/mouse) reduced macrophage phagocytosis from peripheral blood mononuclear cells, but did not affect phagocytosis by macrophages from the peritoneal cavity. At an effector:target ratio of 50:1, laminarin reduced NK cell cytotoxic activity at all levels, but at a ratio of 25:1, only at 1 mg treatment. Laminarin did not affect T-cell and B-cell proliferation. Laminarin increased the level of GPT and reduced that of LDH at all doses, indicating laminarin can protect against liver injury. Laminarin is worthy of investigation in future experiments on improving immune responses.