Studi Pengaruh Ekstrak Kasar Polisakarida Jamur Tiram Putih, Pleurotus ostreatus (Jacq.) P. Kummer, 1871, sebagai Imunomodulator Aktivitas Fagositik Sel Makrofag RAW 264.7 = Study of the Effect of Crude Polysaccharide Extract from White Oyster Mushroom, Pleurotus ostreatus (Jacq.) P. Kummer, 1871, as Immunomodulator on Phagocytic Activity of Macrophage Cells RAW 264.7