Anti-β2GP1 antibodies have variable effects on platelet aggregation

Betts, N.A., Ahuja, K.D.K. and Adams, M.J.ORCID: 0000-0002-7743-4515 (2013) Anti-β2GP1 antibodies have variable effects on platelet aggregation. Pathology, 45 (2). pp. 155-161.

Abstract

Aim

To investigate the effects of affinity-purified rabbit anti-β2GP1, and anti-β2GP1 purified from patients with systemic lupus erythematosus (SLE), on adenosine diphosphate (ADP)-induced aggregation.

Methods

Whole blood was collected and processed to obtain platelet poor plasma (PPP) from normal controls (n = 15) and SLE patients (n = 15). Using PPP, anti-β2GP1 titres were determined using an ELISA and IgG fractions isolated using a HiTrap protein G column. Anti-β2GP1 was purified from two SLE patients using purified β2GP1 coupled to a HiTrap NHS-activated HP column.

Results

The effect of rabbit and human derived anti-β2GP1 (0–100μg/mL), on ADP (2.5, 5μM) induced platelet aggregation were investigated using light transmission aggregometry. Rabbit anti-β2GP1 significantly inhibited all parameters of 5μM ADP-induced platelet aggregation; %Max (p = 0.028), %AUC (p = 0.014) and slope (p<0.001). In contrast, anti-β2GP1 purified from SLE patients significantly enhanced the %Max (p = 0.031) and %AUC (p = 0.007) in a concentration dependent manner, but inhibited the slope (p<0.05) of 5μM ADP-induced platelet aggregation.

Conclusion

Our data suggest anti-β2GP1 purified from different species have variable effects on in vitro platelet aggregation. The disparity between rabbit and human anti-β2GP1 may be due to the heterogeneous nature of anti-β2GP1, varying avidity or different antibody binding specificities between species.

Item Type:	Journal Article
Publisher:	Royal College of Pathologists of Australasia
Copyright:	© 2013 Royal College of Pathologists of Australasia
URI:	http://researchrepository.murdoch.edu.au/id/eprint/53623

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