Fractionation and characterization of the immunosuppressive substance in crude extracellular products released by Streptococcus intermedius
| Autor: | M. T. Porto, Helena Geada, Philipe Arnaud, H. Hugh Fudenberg, M.P. Arala-Chaves, Christian C. Patrick, Maria João Saraiva |
|---|---|
| Rok vydání: | 1981 |
| Předmět: |
Erythrocytes
Biology Streptococcus intermedius chemistry.chemical_compound Bacterial Proteins medicine Antigens Chromatography Chymotrypsin Isoelectric focusing Streptococcus Biological activity General Medicine Trypsin biology.organism_classification Molecular Weight Isoelectric point chemistry Biochemistry Sephadex biology.protein Immunization Lymphocyte Culture Test Mixed Methylene blue Immunosuppressive Agents medicine.drug Research Article |
| Zdroj: | The Journal of clinical investigation. 68(1) |
| ISSN: | 0021-9738 |
| Popis: | The noncytotoxic immunosuppressive substance detected in crude extracellular products of Streptococcus intermedius (CEP-SI) was fractionated by two steps of preparative isoelectric focusing in sucrose gradients using ampholytes of pH range from 3.5 to 6 and 4 to 5, respectively. The in vitro and in vivo suppressor effects of the most highly purified fraction of CEP-Si, designated fraction 3' (F3'EP-Si), corresponded well with those of the original CEP-Si. F3'EP-Si was sensitive to the effects of alpha, gamma, and delta chymotrypsin, trypsin, and heating. It contained approximately 1% of the total amount of protein found in the original CEP-Si, corresponding to a single band on analytical isoelectric focusing, stainable by Coomassie Blue and of isoelectric point of 4.25. The absorption spectrum of F3'EP-Si had a maximum at 260 nm but its biological activity was resistant to deoxyribonuclease and ribonuclease A and it did not contain material stainable by methylene blue. It was also resistant to neuraminidase and did not contain material stainable by periodic acid schiff. We conclude that the substance responsible for the suppressor activity of CEP-Si is a protein of molecular weight approximately 90,000, which adheres to Sephadex of cellulose acetate and forms complexes with other, nonactive constituents of CEP-Si. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|