抄録
Plasma fibronectin (FN) binding to bacteria and its effect of the opsonic activity on the phagocytosis of them by human alveolar macrophages (AM) was investigated. The binding of 125I-FN to Staphylococcus aureus (S. aureus: 209-P) was proportional to the amount of FN added, and was inhibited by adding non-ladiolabeled FN. Haemophilus influenzae (H. inf: 85-237) was less reactive than S. aureus. FN alone was a poor opsonin for S. aureus, but FN promoted the phagocytosis of S. aureus by AM in dose dependent manner on condition that the reactions were carried out with FN depleted serum at the higher bacteria to AM ratio. On the other hand, the phagocytosis of H. inf was not affected by FN at the higher bacteria to AM ratio. These results suggested that FN binding to bacteria might contribute to the promotion of the bacterial phagocytosis by AM in cooperation with serum factor.
