How many subclasses exist for IgG?

How many subclasses exist for IgG?

• A. 4
• B. 3
• C. 2
• D. 5

Answer: (A)

IgG has four subclasses in humans: IgG1, IgG2, IgG3, and IgG4. Each subclass has slight differences in the hinge region and Fc portion, which shape its ability to activate complement and bind Fc receptors, influencing how strongly it flags pathogens for destruction or interacts with immune cells. IgG1 and IgG3 are particularly effective at triggering effector functions, IgG2 is more common against polysaccharide antigens, and IgG4 tends to be less inflammatory and can even exchange Fab arms. Because these distinct forms exist, the total number of IgG subclasses is four.

IgG has four subclasses in humans: IgG1, IgG2, IgG3, and IgG4. Each subclass has slight differences in the hinge region and Fc portion, which shape its ability to activate complement and bind Fc receptors, influencing how strongly it flags pathogens for destruction or interacts with immune cells. IgG1 and IgG3 are particularly effective at triggering effector functions, IgG2 is more common against polysaccharide antigens, and IgG4 tends to be less inflammatory and can even exchange Fab arms. Because these distinct forms exist, the total number of IgG subclasses is four.