Assays for Quantification of Anti-HPA-1a Antibodies

A method of measuring pharmacokinetics of anti-HPA-1a antibodies administered to a subject, the method comprising:

• (a) contacting a sample from the subject with a capture reagent that binds to the anti-HPA-1a antibodies to form a detection complex, wherein the capture reagent comprises a modified integrin β3;
• and
• (b) measuring an amount of the detection complex, wherein the amount of the detection complex indicates the quantity of the anti-HPA-1a antibodies in the sample;
• wherein the quantity of the anti-HPA-1a antibodies in the sample is used to calculate the pharmacokinetics of the anti-HPA-1a antibodies administered to the subject.

A method of quantifying anti-HPA-1a antibodies in a sample, the method comprising:

• (a) contacting the sample with a capture reagent that binds to the anti-HPA-1a antibodies, wherein the capture reagent comprises a modified integrin β3 comprising the amino acid sequence of SEQ ID NO:
• 2;
• (b) contacting the sample with a detecting reagent that binds to the anti-HPA-1a antibodies, wherein the detecting reagent comprises an antibody or antigen-binding fragment thereof that binds to the anti-HPA-1a antibodies and a detectable label attached thereto, and wherein the anti-HPA-1a antibodies, the capture reagent, and the detecting reagent forms a detection complex;
• and
• (c) measuring an amount of the detection complex, wherein the amount of the detection complex indicates the quantity of the anti-HPA-1a antibodies in the sample.

A method of determining potency of anti-HPA-1a antibodies in a sample, the method comprising:

• (a) contacting the sample with a capture reagent that binds to the anti-HPA-1a antibodies, wherein the capture reagent comprises a modified integrin β3 comprising the amino acid sequence of SEQ ID NO:
• 2;
• (b) contacting the sample with a detecting reagent that binds to the anti-HPA-1a antibodies, wherein the detecting reagent comprises an antibody or antigen-binding fragment thereof that binds to the anti-HPA-1a antibodies and a detectable label attached thereto, and wherein the anti-HPA-1a antibodies, the capture reagent, and the detecting reagent forms a detection complex;
• and
• (c) measuring an amount of the detection complex, wherein the amount of the detection complex indicates the potency of the anti-HPA-1a antibodies in the sample.

A method of measuring pharmacokinetics of anti-HPA-1a antibodies administered to a subject, the method comprising:

• (a) contacting a sample from the subject with a capture reagent that binds to the anti-HPA-1a antibodies, wherein the capture reagent comprises a modified integrin β3 comprising the amino acid sequence of SEQ ID NO:
• 2;
• (b) contacting the sample with a detecting reagent that binds to the anti-HPA-1a antibodies, wherein the detecting reagent comprises an antibody or antigen-binding fragment thereof that binds to the anti-HPA-1a antibodies and a detectable label attached thereto, and wherein the anti-HPA-1a antibodies, the capture reagent, and the detecting reagent forms a detection complex;
• and
• (c) measuring an amount of the detection complex, wherein the amount of the detection complex indicates the quantity of the anti-HPA-1a antibodies in the sample.