Use of monoclonal antibodies to study the interaction between an integrin adhesion receptor, GP IIb-IIIa, and its physiological ligand, fibrinogen

Antibodies to serotonin attenuate closed head injury induced blood brain barrier disruption and brain pathology

Closed head injury (CHI) often results in profound brain swelling and instant death of the victims due to compression of the vital centers. However, the neurochemical basis of edema formation in CHI is still obscure. Previous studies from our laboratory show that blockade of serotonin synthesis prior to CHI in a rat model attenuates brain edema, indicating a prominent role for serotonin in head injury. Thus, neutralization of endogenous serotonin activity and/or blocking of its receptors will induce neuroprotection in CHI. Since serotonin has more than 14 receptors and selective serotonin antagonists are still not available, we used serotonin antiserum to neutralize its in vivo effects before or after CHI in a rat model. CHI was produced by an impact of 0.224 N on the right parietal skull bone under Equithesin anesthesia by dropping a weight of 114.6 g from a height of 20 cm through a guide tube. This concussive brain injury resulted in blood-brain barrier (BBB) disruption, brain edema formation, and volume swelling at 5 h that were most pronounced in the contralateral cerebral hemisphere. The plasma and brain serotonin levels were increased several-fold at this time. Intracerebroventricular administration of serotonin antiserum (1:20, monoclonal) into the left lateral cerebral ventricle (30 microL in PBS) 30 min before or 30 min (but not 60 min) after CHI significantly attenuated BBB disruption, brain edema formation, volume swelling, and brain pathology. The plasma and brain serotonin levels continued to remain high. These observations are the first to suggest that antiserum to serotonin when administered into the CSF during the early phase of CHI are capable of inducing neuroprotection.

Topical application of 5-HT antibodies reduces edema and cell changes following trauma of the rat spinal cord

Involvement of serotonin in the early microvascular reactions and cell changes following trauma of the spinal cord was examined using topical application of serotonin antibodies to the traumatised cord in a rat model. A focal trauma of the spinal cord was produced by making an incision into the right dorsal horn of the T10-11 segments (about 2 mm deep and 5 mm long); the animals were allowed to survive 5 h after injury. Monoclonal 5-HT antibodies (1:20) were applied (25 microliters in 10 sec) to the traumatised spinal cord 2 min after injury. There was a significant reduction in the breakdown of the blood-spinal cord barrier, edema formation, and cell changes in the traumatised rats which received 5-HT antiserum compared to the injured rats given saline. These results show that 5-HT is an important mediator involved in the early pathophysiological responses of spinal cord injury.

Two monoclonal antibodies from the platelet panel recognize sheep plasma fibrinogen

Among the monoclonal antibodies (mAbs) submitted to the third Workshop, two mAbs, IVA120 (3W-323) and IVA198 (3W-290), could be identified to recognize the sheep fibrinogen molecule. The apparent molecular weight of the immunoprecipitated 48-60 kDa cell surface protein under reducing conditions suggested this antigen could be the fibrinogen molecule. ELISA and immunoblotting assays, performed with commercially available sheep plasma fibrinogen, confirmed that these two mAbs recognize two different epitopes present on the sheep fibrinogen molecule.