Which statement best describes immune antibodies in terms of immunoglobulin class?

Which statement best describes immune antibodies in terms of immunoglobulin class?

• A. They are primarily IgM
• B. They are primarily IgG
• C. They are primarily IgA
• D. They are a mix of IgG and IgM

Answer: (B)

Immune antibodies formed after exposure to an antigen are predominantly of the IgG class. After initial exposure, B cells often switch from producing IgM to IgG, and with repeated exposure (memory response) IgG becomes the main antibody produced. This IgG response has higher affinity due to maturation and can persist longer, enabling effective targeting of antigens on cells like red blood cells. In transfusion immunology, clinically significant alloantibodies are usually IgG and are detected at body temperature or with the antiglobulin test, reflecting their role in real immune challenges. IgM antibodies, while potent early responders and good at causing immediate agglutination, are typically natural or primary-response antibodies and are not the main class after antigen exposure. IgA, meanwhile, is mainly involved in mucosal immunity and isn’t the primary class for systemic immune antibodies against RBC antigens. So the statement that immune antibodies are primarily IgG best captures the typical class produced after antigen exposure.

Immune antibodies formed after exposure to an antigen are predominantly of the IgG class. After initial exposure, B cells often switch from producing IgM to IgG, and with repeated exposure (memory response) IgG becomes the main antibody produced. This IgG response has higher affinity due to maturation and can persist longer, enabling effective targeting of antigens on cells like red blood cells. In transfusion immunology, clinically significant alloantibodies are usually IgG and are detected at body temperature or with the antiglobulin test, reflecting their role in real immune challenges. IgM antibodies, while potent early responders and good at causing immediate agglutination, are typically natural or primary-response antibodies and are not the main class after antigen exposure. IgA, meanwhile, is mainly involved in mucosal immunity and isn’t the primary class for systemic immune antibodies against RBC antigens. So the statement that immune antibodies are primarily IgG best captures the typical class produced after antigen exposure.