IGA IS A BILE DUCT GROWTH FACTOR
| Autor: | Sheila Fallon-Friedlander, Marshall S. Horwitz, Joy H. Glaser, Jeffrey R. Boscamp, Rachel Morecki |
|---|---|
| Rok vydání: | 1987 |
| Předmět: | |
| Zdroj: | Pediatric Research. 21:264A-264A |
| ISSN: | 1530-0447 0031-3998 |
| Popis: | We have discovered a bile duct growth factor (BDGF) in serum which causes non-neoplastic proliferation of extrahepatic bile duct (EHBD) epithelium. BDGF activity was determined after 7 intraperitoneal injections of serum or serum fractions given every other day to BALB/c mice which were dissected for gross and microscopic study of the EHBD. The duct enlargement, up to seven times normal, occurred without luminal obstruction and without other tissue involvement. Early characterization demonstrated that the BDGF was a thermostable protein located in the 33-65% ammonium sulfate (AS) precipitate of serum and susceptible to proteases only after denaturation in 1% SDS. (Hepatology, in press). The active 33-65% AS fraction was chromatographed on a G-75 sephadex column from which the BDGF eluted at a higher molecular mass than albumin. Affinity chromatography utilizing concanavalin A-sepharose or lentil-lectin demonstrated BDGF activity in the methyl mannoside elute, indicating it was a glycoprotein. Since the BDGF was also present in bile as well as breast milk and had many of the properties of IgA, we tested chromatographically purified human IgA for BDGF activity. Isolated IgA (2mg/ml) was as active as whole serum while serum depleted of IgA by affinity chromatography produced no BDGF response. Calf serum was also positive for BDGF but fetal calf serum, naturally devoid of IgA, was negative. The only IgA-containing sera without BDGF activity was BALB/c mouse sera. We conclude, therefore, that heterologous IgA is a growth factor for the EHBD. The mechanism by which heterologous IgA enhances bile duct growth is being explored. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|