S Nakaike — Page 3 | Search PubMed

PubMed1981

Studies of D-penicillamine (3): immunomodulating effects of D-penicillamine.

D-penicillamine (D-PA) has beneficial therapeutic effects for patients with rheumatoid arthritis but no convincing explanation has been offered for the mode of action. Experiments reported here were designed to gain an insight into the related mechanisms. Wistar rats were inoculated with various doses of Mycobacterium tuberculosis to induce adjuvant arthritis, and on the 21st day, the lesions of paws and ears were graded according to the extent of the erythema and swelling. Rats given D-PA simultaneously with the inoculation of M. tuberculosis developed a more severe arthritis than that seen in the control group, when they were inoculated with low doses of M. tuberculosis. To investigate the effect of D-PA on hemolytic plaque forming cells (PFC) in the spleen, BDF1 mice were immunized with various doses of sheep red blood cells (SRBC) and D-PA was injected in various doses and at various times. D-PA produced either enhancement or depression of the number of PFC, depending on the dose of antigenic stimulus of SRBC. Furthermore, D-PA slightly enhanced the concanavalin A-induced blastogenesis of the spleen cells in vitro, at a concentration of 1-50 microM, but at concentrations of 500 microM, inhibition was evident. These results indicate that D-PA may act as an immunomodulating agent.

Adjuvants, Immunologic↗

PubMed1977

Detergent-resistant phospholipase A of Escherichia coli K-12. Purification and properties.

Detergent-resistant phospholipase A, which is tightly bound to the outer membranes of Escherichia coli K-12 cells, was purified approximately 2000-fold to near homogeneity by solubilization with sodium dodecylsulfate and butan-1-ol, acid precipitation, acetone fractionation and column chromatographies on Sephadex G-100 in the presence of sodium dodecylsulfate and on DEAE-cellulose in the presence of Triton X-100. The final preparation showed a single band in the sodium dodecylsulfate gel system. The enzyme hydrolyzes both the 1-acyl and 2-acyl chains of phosphatidylethanolamine or phosphatidylcholine. It also attacks 1-acyl and 2-acylglycerylphosphorylethanolamine. Thus, this enzyme shows not only phospholipase A1 and lysophospholipase L1 activities but also phospholipase A2 and lysophospholipase L2 activities. The enzyme lost its activity completely on incubation at 80 degrees C for 5 min at either pH 6.4 or pH 8.0. It was stable in 0.5% sodium dodecylsulfate at below 40 degrees C. The enzyme was inactivated on incubation for 5 min at 90 degrees C in 1% sodium dodecylsulfate/1% 2-mercaptoethanol/4 M urea. The native and inactivated enzymes showed different protein bands with RF values corresponding to Mr 21 000 and Mr 28 000 respectively, in a sodium dodecylsulfate gel system. Triton X-100 seemed to protect the enzyme from inactivation. The purified enzyme was fully active on phosphatidylethanolamine in the presence of 0.0002% or 0.05% Triton X-100. The enzyme requires Ca2+. From its properties this enzyme seems to be identical with the enzyme purified from crude extracts of Escherichia coli B by Scandella and Kornberg. However, it differs from the latter in its positional specificity and susceptibility to sodium dodecylsulfate. Possible explanation of the difference of positional specificity of the two preparations is also described.

Drug Stability↗