HETEROPHILIC AGGREGATION AND GELATION OF PLASMA-PROTEINS BY CELL-ADHESION PROTEIN

Cryogel is a coprecipitate of a cell adhesion protein with human plasm a proteins produced from patient plasma. Cryogel is insoluble at a low temperature (4 degrees C), and it is soluble at a high temperature (3 7 degrees C). The diseases producing cryogel are rheumatoid arthritis, thrombosis, and so on. Cryogel is a physical gel formed by the hetero philic aggregation of EDA(+)fibronectin (EDA(+)FN), plasma fibronectin (pFN), fiburinogen (Fbg), and heparin (Hep). EDA(+) FN is a cell adhe sion protein that does not exist in the blood, pFN and Fbg are plasma proteins, and Hep is a glucosaminoglycan. In this report, we describe the interaction of the cryogel composition molecules, and the conditio n of cryogel formation. The binding constant (KA) is measured by surfa ce plasmon resonance (SPR). The order of strength for the interaction was Fbg-Hep > EDA( +)FN-Hep > Fbg-Fog > Fbg-EDA( +)FN > Hep-pFN > Fbg- pFN. Hep-EDA(+)FN affinity is about 70 times bigger than that of Hep-p FN. It is thought that cryogel formation is controlled by the balance between aggregation size and aggregation concentration. So, the most s uitable gelation condition was examined from the diffusion coefficient of the aggregate and the amount of aggregate by the dynamic light sca ttering measurement and the turbidity measurement. It was found that t he cryogel grew around the self-aggregate of Fbg from the temperature dependence of diffusion coefficient. The diffusion coefficient ratio a t a low temperature (5 degrees C) became 1/1000 by adding Hep and EDA( +)FN into Fbg. On the other hand, the amount of aggregate by the three -element Fbg-Hep-pFN was much more than that of Fbg-Hep-EDA(+)FN. In o ther words, an important factor is the ratio of EDA(+)FN to pFN for th e cryogel formation. Aggregation occurred most efficiently at EDA(+)FN : pFN:Fbg:Hep = 0.05 :0.95 : 15: 1 (mol%). Cryogelation is thus the Fb g-pFN aggregations of plasma proteins crosslinked by EDA(+)FN-Hep aggr egates.