An antiserum is __________:
a. An anti-antibody
b. An inactivated vaccine
c. Formed of monoclonal antibodies
d. The liquid portion of blood used for immunization

Verified step by step guidance

1. Understand the term 'antiserum' in the context of immunology. Antiserum is a blood-derived fluid that contains antibodies specific to certain antigens.
2. Recall that antiserum is typically obtained from the blood after an individual or animal has been exposed to an antigen and has produced antibodies against it.
3. Recognize that antiserum is not an anti-antibody (which would be an antibody against another antibody), so option (a) is incorrect.
4. Note that antiserum is not an inactivated vaccine; vaccines stimulate active immunity, whereas antiserum provides passive immunity by supplying ready-made antibodies, so option (b) is incorrect.
5. Understand that antiserum is usually polyclonal (contains a mixture of antibodies), not monoclonal (which are identical antibodies from a single clone), so option (c) is incorrect. Therefore, the correct description is that antiserum is the liquid portion of blood containing antibodies used for immunization, matching option (d).

Key Concepts

Antiserum

Antiserum is a blood serum containing antibodies that are specific to certain antigens. It is used to provide passive immunity by directly supplying antibodies to an individual, helping to neutralize pathogens or toxins.

Antibodies and Monoclonal Antibodies

Antibodies are proteins produced by B cells that recognize and bind to specific antigens. Monoclonal antibodies are identical antibodies produced by a single clone of cells, used in targeted therapies and diagnostics, but antiserum typically contains a mixture of antibodies.

Difference Between Serum and Plasma

Serum is the liquid portion of blood after clotting, lacking clotting factors, and contains antibodies. Plasma is the liquid portion of blood before clotting and contains clotting factors. Antiserum refers specifically to serum rich in antibodies used for immunization.