Question

After an adaptive defense is produced against a pathogen, typically plasma cells first secrete immunoglobin, which constitutes about ten percent of all what?

Answer 1

antibodies

After an adaptive defense is produced against a pathogen, typically plasma cells first secrete IgM into the blood. BCRs on nave B cells are of the IgM class and occasionally IgD class. IgM molecules make up approximately ten percent of all antibodies. Prior to antibody secretion, plasma cells assemble IgM molecules into pentamers  five individual antibodies  linked by a joining  J  chain, as shown in Figure 42.23. The pentamer arrangement means that these macromolecules can bind ten identical antigens. However, IgM molecules released early in the adaptive immune response do not bind to antigens as stably as IgGs, which are one of the possible types of antibodies secreted in large quantities upon re-exposure to the same pathogen. Figure 42.23 summarizes the properties of immunoglobulins and illustrates their basic structures.