SARS-CoV-2 Spike Protein and Neutralizing Anti-Spike Protein Antibodies Modulate Blood Platelet Function

Area of Science:

• Immunology
• Hematology
• Virology

Background:

• COVID-19 is associated with altered platelet counts and activation.
• The specific role of the SARS-CoV-2 spike protein in platelet response is not fully understood.
• The impact of neutralizing antibodies on spike protein-induced platelet changes is unknown.

Purpose of the Study:

• To investigate the in vitro effects of the SARS-CoV-2 spike protein on blood platelet aggregation and activation.
• To determine if anti-SARS-CoV-2 neutralizing antibodies can modulate these spike protein effects.

Main Methods:

• In vitro experiments using isolated platelets and whole blood.
• Assessed collagen- and ristocetin-induced platelet aggregation.
• Measured von Willebrand factor (vWF) binding and GPIIbIIIa activation.

Main Results:

• Spike protein increased collagen-stimulated platelet aggregation and vWF binding.
• Spike protein reduced collagen- or ADP-induced aggregation and GPIIbIIIa activation in whole blood.
• These modulatory effects were dependent on the presence of anti-spike protein neutralizing antibodies.

Conclusions:

• The SARS-CoV-2 spike protein directly influences platelet aggregation and activation.
• Anti-spike protein neutralizing antibodies can attenuate the spike protein's effects on platelets.
• Measuring spike protein and antibody levels is crucial in studies of COVID-19 patients and vaccinated individuals.