ABSTRACT
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177 Spirulina and the Innate Immune System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
Macrophage Phagocytosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 Macrophage Chemokine and Cytokine Production . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 Inflammation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
Prostaglandins and Leukotrienes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181 Reactive Oxygen and Nitrogen Species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181 Animal Models of Inflammatory Diseases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184
Allergic Inflammation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184 NK Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
Spirulina in Adaptive Immune Responses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187 Antibody Production by B Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187 Effect on T Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188 Spirulina and the Generation of Immune Cells (Hematopoiesis) . . . . . . . . . . . . 189 Absorption of Spirulina Constituents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
Concluding Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
The main function of the immune system in humans and animals is to detect and then neutralize or destroy invading pathogens, such as viruses, bacteria, fungi, and parasites. In addition, it is responsible for eliminating worn-out and abnormal self-cells. For these purposes, two types of immune responses have evolved, classified as innate and adaptive. Innate immune responses are also called nonspecific because they can be triggered by certain molecular patterns common to whole classes of pathogens and do not vary in subsequent encounters with the same antigen. The major mechanisms of innate immunity include phagocytosis, inflammation, complement activation, and induction of cell death. The main classes of phagocytes, that is, cells able to engulf entire bacteria or particulate matter, are neutrophils and macrophages. The chemical messengers they and some other cell types produce play an important role in the initiation of an inflammatory response. The killing of virus-infected cells and cancer
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cell death or by natural killer (NK) cells.
