Inhibition of ras by farnesylthiosalicylate significantly reduces the levels of autoantibodies in two animal models of the antiphospholipid syndrome.
BACKGROUND
Stimulation and proliferation of lymphocytes require activation of Ras. S-farnesylthiosalicylic acid (FTS) is a synthetic substance that detaches Ras from the inner cell membrane and induces its rapid degradation. Antiphospholipid antibodies (aPL) are a heterogeneous group of antibodies detected in patients with antiphospholipid syndrome (APS), which is associated with thrombosis, pregnancy losses, and thrombocytopenia.


OBJECTIVE
To examine the effect of FTS treatment on aPL levels in a genetic autoimmune model (the MRL/lpr mice) and in an induced model of APS.


METHODS
Female Balb/C mice immunized once with beta2-glycoprotein I (beta2-GPI) in complete Freund's adjuvant (CFA) and female MRL/lpr mice were treated intraperitoneally with either FTS (5 mg/Kg/day) or saline 3-5 times a week. aPL and anti-beta2-GPI antibodies were measured by ELISA.


RESULTS
FTS treatment 3 times a week resulted in significant decreases of aPL and anti-beta2-GPI antibodies in both animal models. In contrast, more frequent treatment (5 times a week) had no significant effect on autantibody levels in both animal models. We further compared 2 protocols in the induced APS model, one for alternate day treatment and the other for daily treatment on the first 3 days each week, and found a decrease in autoantibody levels only in the alternate day protocol.


CONCLUSIONS
Inhibition of Ras activation by FTS is effective in decreasing autoantibody levels in models of APS. The differential modulation of immune function by alternate day compared to daily treatment may provide better understanding of the role of Ras activation in this system.
Katzav
Aviva
A
Dept. of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv, Israel.
Kloog
Yoel
Y
Korczyn
Amos D
AD
Molina
Vered
V
Blank
Miri
M
Shoenfeld
Yehuda
Y
Chapman
Joab
J
D000818:Animals; D017152:Antibodies, Antiphospholipid / Q000097:blood / Q000276:immunology; D016736:Antiphospholipid Syndrome / Q000097:blood* / Q000276:immunology; D001323:Autoantibodies / Q000097:blood*; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D004797:Enzyme-Linked Immunosorbent Assay; D005204:Farnesol / Q000031:analogs & derivatives* / Q000494:pharmacology*; D005260:Female; D005620:Freund's Adjuvant / Q000494:pharmacology; D006023:Glycoproteins / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D019463:Mice, Inbred MRL lpr; D012459:Salicylates / Q000494:pharmacology*; D013997:Time Factors; D053482:beta 2-Glycoprotein I; D018631:ras Proteins / Q000037:antagonists & inhibitors*
D017152:Antibodies, Antiphospholipid; D001323:Autoantibodies; D004791:Enzyme Inhibitors; D006023:Glycoproteins; D012459:Salicylates; D053482:beta 2-Glycoprotein I; C093323:farnesylthiosalicylic acid; D005204:Farnesol; D005620:Freund's Adjuvant; D018631:ras Proteins