Induction of high levels of anticardiolipin antibodies in mice by immunization with beta 2-glycoprotein I does not cause fetal death.

OBJECTIVE

Our purpose was to determine whether anticardiolipin antibodies induced by immunization with beta 2-glycoprotein I cause fetal death in mice.

METHODS

Female BALB/c mice were immunized with beta 2-glycoprotein I in a carbohydrate adjuvant or with carbohydrate adjuvant alone. The mice were mated with BALB/c males and killed on day 11 to 13 of pregnancy, and the fetal status was determined. Posttreatment blood samples were obtained for measurement of anticardiolipin and anti-beta 2-glycoprotein I antibodies and platelet counts.

RESULTS

Anticardiolipin and anti-beta 2-glycoprotein I antibodies developed in all mice immunized with beta 2-glycoprotein I. Fetal death occurred in 17 of 145 gestational sacs (12%) in 18 mice immunized with beta 2-glycoprotein I compared with 24 of 177 (14%) sacs in 21 control mice. There were no morphometric or histologic differences between gestational tissues, and platelet counts were similar for each group.

CONCLUSIONS

The induction of high levels of anticardiolipin antibodies in BALB/c mice by beta 2-glycoprotein I immunizations did not result in fetal death or thrombocytopenia. These nonpathogenic beta 2-glycoprotein I-induced anticardiolipin antibodies should prove useful in the characterization of clinically relevant epitopes for antiphospholipid syndrome.