spergualin and methyldeoxyspergualin

Deoxyspergualin, an analog of spergualin, has been known as a novel immunosuppressive agent with strong immunosuppressive activity in in vivo experimental systems. In the present study, we examined the effect of deoxyspergualin (DSG) and methyldeoxyspergualin (MeDSG) on the proliferation and differentiation of human B lymphocytes in vitro. Highly purified B cells from human tonsil samples were isolated by Percoll density gradient from nonrosetted cells and were used as target cells. Both agents had little effect on the proliferative response of resting or activated B lymphocytes. However, they suppressed the immunoglobulin synthesis of B lymphocytes not only in a T cell-dependent, but also in a T cell-independent system. The inhibition of antibody synthesis was manifested in the early stage of B cell differentiation. Both drugs also suppressed Ig secretion, but not proliferation, of an EBV-transformed human B lymphoblastoid cell line. These results indicate that DSG and MeDSG have a selective immunosuppressive effect on the differentiation pathway of B lymphocytes.

Topics: Antibody-Producing Cells; B-Lymphocytes; Cell Differentiation; Cell Line, Transformed; Guanidines; Herpesvirus 4, Human; Humans; Immunoglobulins; Immunosuppressive Agents; Kinetics; Lymphocyte Activation; Staphylococcus aureus

Optically active 15-deoxyspergualin (II) and 15-deoxy-11-O-methylspergualin (IIa) were synthesized, and their antitumor activities were examined. The (-)-enantiomers of both II and IIa were active against mouse leukemia L1210, while the (+)-enantiomers were almost inactive. The optical resolution of the key intermediate, (+/-)-N-(7-guanidinoheptanoyl)-alpha-alkoxyglycine (VI) was achieved by use of an exopeptidase, serine (acid) carboxypeptidase [EC 3.4.16.1] and (+/-)-N-(7-guanidinoheptanoyl)-alpha-alkoxyglycyl-L-amino acid (VIII) as the substrate. Considering the enzymatic susceptibility of the substrate (VIII), we deduced that the absolute configuration of the carbon at 11 (C-11) of the bioactive (-)-enantiomer, and so that of natural spergualin (I), is S. This is, to our knowledge, the first report of the use of carboxypeptidase for the resolution of N-acyl amino acid.

Topics: Animals; Antibiotics, Antineoplastic; Guanidines; Leukemia L1210; Magnetic Resonance Spectroscopy; Mice