| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1989: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1988: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
In order to clarify the biological significance of myelin basic protein (MBP) immunoreactive substance in tumor cells, we investigated if or not tumor basic protein (TBP), acid extracts of tumor tissues, possess the MBP immunoreactive substance, which could have amino acid components somehow similar to MBP.
Various types of tumor tissues from various origins were obtained at autopsy or surgery and submitted for the present study. The acid extracts of tumor tissue were obtained as follows; The tissues were homogenized with ice-cold distilled water, and the resulting homogenate was centrifuged. The supernatant discarded and the tissue pellet rehomogenized with ice-cold water. This procedure was repeated twice and the final pellets dispersed into ice-cold acetone and stirred in the cold room for overnight. The defatted tissue was removed from the acetone by filtration, and the filter cake dispersed into ice-cold water. The pH of the tissue suspension was adjusted to about 2 and stirred in
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the cold for overnight. After acid extraction the suspension was centrifuged and the supernatant dialysed against distilled water until neutral. The dialysate was freeze-dry. The protein compositions of the crude extracts of the tumor tissues were determined by SDS-polyacrylamide gel electrophoresis in 12% gels. Then, an immunoblotting technique was used in the detection of immunologically cross-reacting proteins in the ctude extracts. The antibody used in the present study was anti-MBP serum, which was made in the following procedures. It was obtained from white rabbit two months after weekly subcutaneous injections of 0.5 mg of porcine spinal cord MBP in Freund's complete adjuvant. The serum was heat-inactivated at 56ﾟC for 30 min. The specificity of the serum was confirmed by the same immunoblotting procedures.
As the results, the TBP from various tumors were clearly found to possess at least four or five bands which cross-reacted with anti-MBP, ranging from about 35,000 to 65,000 in molecules, suggesting that TBP contains persistently certain common epitope and/or polymer form of MBP which are cross-reactive with the present anti-MBP antibody. The universal appearance of MBP reactive substance in acid extracts of tumor tissues, regardless of the origin and histologic typings, strongly suggests that MBP immunoreactive substance in tumor cells could play an important biological role, probably as a mitogen, in the tumor growth. Less
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