Reconstituted basement membrane complex with biological activity

A biologically active extract for promoting cell growth and differentiation derived from Engelberth-Holm-Swarm tumor by a process carried out at about 4.degree. C. comprising the sequential steps of:

• (a) homogenizing the tumor multiple times in a suitable first buffer containing at least 3.4M salt and discarding the soluble fraction after each homogenization so as to remove undesirable components;
• (b) extracting the residual tumor in a suitable urea buffer containing at leat 2M urea keeping the extract stirred for about 16-18 hours;
• (c) separating the extract form step (b) and saving the extract while repeating step (b) with the residual tumor fraction and again saving the extract resulting therefrom;
• (d) combining the extracts from step (c) and dialyzing against a suitable sterilizing buffer with multiple changes of the dialyzing buffer;
• (e) further dialyzing against a suitable buffer not containing a sterilizing component;
• (f) recovering a dialysate from step (e);
• and
• (g) polymerizing the dialysate at 24.degree.-32.degree. C. for at least 20 minutes, said dialysate in a concentration of at least 3.7 mg/ml containing in parts by weight about 60-85% laminin, 5-30% collagen IV, 1-10% nidogen, 1-101% heparin sulfate proteoglycan and 1-5% entactin.

A biologically active extract for promoting cell growth and differentiation derived from human placental tissue by a process carried out at about 4.degree. C. comprising the sequential steps of:

• (a) homogenizing placental tissue multiple times in a suitable first buffer containing at least 3.4M salt and discarding the soluble fraction after each homogenization so as to remove undesirable components;
• (b) extracting the residual tissue in a suitable urea buffer containing at least 2M urea and keeping the extract stirred for about 16-18 hours;
• (c) separating the extract from step (b) and saving the extract while repeating step (b) with the residual tissue fraction and against saving the extract resulting therefrom;
• (d) combining the extracts from step (c) and transferring to a heparin affinity column to allow adsorption and then eluting the bound material with a salt solution of greater than physiological concentration;
• (e) dialyzing the eluate against a sterilizing buffer with multiple changes of the sterilizing buffer;
• (f) further dialyzing against a suitable buffer not containing a sterilizing component;
• (g) recovering a dialysate from step (f);
• and
• (h) polymerizing the dialysate at 24.degree.-37.degree. C. for at least 20 minutes, said dialysate being a protein extract.