Analysis of the immunoactivator sites of parotid protein isolated from bovine parotid glands

Effect of tetra-peptide isolated from interleukin 1 (IL-1) on corneal epithelial wound healing in the rabbit

To develop a new method for wound healing in case of injured corneal epithelium, the effects of the tetrapeptide (Val-Leu-Leu-Lys), showing the consensus sequence between human interleukin (IL)-1alpha and bovine parotid protein (parotin) on epithelial cell proliferation and elongation were analysed in vitro cell culture experiments on epithelial cells obtained from rabbit cornea. The peptide showed dose-dependent stimulatory effects on epithelial cell proliferation and elongation at 10-100 microg ml(-1)compared with the control experiments. Furthermore, the peptide also exhibited a significant wound healing activity for the epithelial cells in an in situ experiment using mechanically injured rabbit cornea, while the higher concentration of the peptide (100 microg ml(-1)) showed greater efficient results than a previously known agent, sodium hyaluronate (0.3%). In addition, no pyrogenic activity of this peptide was detected by the previously established pyrogenicity test using rabbits. These results suggest that the tetrapeptide (Val-Leu-Leu-Lys) is a promising agent for wound healing in the case of injured corneal epithelium.

Parotin subunit and its synthetic peptide possess interleukin 1-like activity and exert stimulating effects on liver cells and brain cells

We have investigated whether parotin subunit (PS) and its partial synthetic peptide (P-10.2: TDDTAIVLLK), possess interleukin 1 (IL-1)-like activities, and act on cell lines other than lymphocytes. When Chang liver cells were cultured with P-10.2, PS or IL-1, P-10.2 and PS augmented the growth of Chang liver cells. On the other hand, IL-1 enhanced the growth of Change liver cells at 1 day of the initial culture and subsequently failed to enhance during at least 4-day incubation. Next, effects of P-10.2 and PS on the growth of Alexander cells and MH134 were investigated. The proliferation of Alexander cells was inhibited with P-10.2 or PS but not with IL-1. P-10.2 inhibited the growth of MH134 at day 1 and 3, while the growth of MH134 was shown not to be inhibited with PS and IL-1 at day 1, but rather suppressed them at day 3. These results suggest that P-10.2 augments the growth of non-malignant liver cells (Chang liver cells) but inhibits that of hepatoma cells (Alexander cells and MH134). P-10.2 enhanced fibrinogen and hepatoglobin secretion from Chang liver cells. In addition to their liver cell activation, P-10.2 and PS stimulated ACTH and beta-endorphin secretion from AtT-20 cells.