We previously reported that some human antiphospholipid Abs (aPL) in patients with the antiphospholipid syndrome (APS) bind to the homologous enzymatic domains of thrombin and the activated coagulation factor X (FXa). Moreover, some of the reactive Abs are prothrombotic and interfere with inactivation of thrombin and FXa by antithrombin (AT). Considering the enzymatic domain of activated coagulation factor IX (FIXa) is homologous to those of thrombin and FXa, we hypothesized that some aPLs in APS bind to FIXa and hinder AT inactivation of FIXa. To test this hypothesis, we searched for IgG anti-FIXa Abs in APS patients. Once the concerned Abs were found, we studied the effects of the Ab on FIXa inactivation by AT. We found that 10 of 12 patient-derived monoclonal IgG aPLs bound to FIXa and that IgG anti-FIXa Abs in APS patients were significantly higher than those in normal controls (p < 0.0001). Using the mean + 3 SD of 30 normal controls as the cutoff, the IgG anti-FIXa Abs were present in 11 of 38 (28.9%) APS patients. Importantly, 4 of 10 FIXa-reactive monoclonal aPLs (including the B2 mAb generated against β2-glycoprotein I significantly hindered AT inactivation of FIXa. More importantly, IgG from two positive plasma samples were found to interfere with AT inactivation of FIXa. In conclusion, IgG anti-FIXa Ab occurred in ∼30% of APS patients and could interfere with AT inactivation of FIXa. Because FIXa is an upstream procoagulant factor, impaired AT regulation of FIXa might contribute more toward thrombosis than the dysregulation of the downstream FXa and thrombin.

With the advent of sperm sex sorting methods and computer-aided sperm analysis platforms, comparative 2D motility studies showed that there is no significant difference in the swimming speeds of X-sorted and Y-sorted sperm cells, clarifying earlier misconceptions. However, other differences in their swimming dynamics might have been undetectable as conventional optical microscopes are limited in revealing the complete 3D motion of free-swimming sperm cells, due to poor depth resolution and the trade-off between field-of-view and spatial resolution. Using a dual-view on-chip holographic microscope, we acquired the full 3D locomotion of 235X-sorted and 289 Y-sorted bovine sperms, precisely revealing their 3D translational head motion and the angular velocity of their head spin as well as the 3D flagellar motion. Our results confirmed that various motility parameters remain similar between X- and Y-sorted sperm populations; however, we found out that there is a statistically significant difference in Y-sorted bovine sperms’ preference for helix-shaped 3D swimming trajectories, also exhibiting an increased linearity compared to X-sorted sperms. Further research on e.g., the differences in the kinematic response of X-sorted and Y-sorted sperm cells to the surrounding chemicals and ions might shed more light on the origins of these results.

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Objective. To test the hypothesis, utilizing 2 experimental mouse models, that plasmin is an important autoantigen that drives the production of certain IgG anticardiolipin (aCL) antibodies in patients with the antiphospholipid syndrome.Methods. BALB/cJ and MRL/MpJ mice were immunized with Freund's complete adjuvant in the presence or absence of human plasmin. The mouse sera were analyzed for production of IgG antiplasmin, IgG aCL, and IgG anti-␤ 2 -glycoprotein I (anti-␤ 2 GPI) antibodies. IgG monoclonal antibodies (mAb) were generated from the plasmin-immunized MRL/MpJ mice with high titers of aCL, and these 10 mAb were studied for their binding properties and functional activity in vitro.Results. Plasmin-immunized BALB/cJ mice produced high titers of IgG antiplasmin only, while plasmin-immunized MRL/MpJ mice produced high titers of IgG antiplasmin, IgG aCL, and IgG anti-␤ 2 GPI.