Fab fregment and small peptide using the vire frame mode CD4 CD8 IgG is the most abundant class of Ig in the body,constituting approximately 75%of the total immunoglobulin and distributed equally within the intravascular and extravasular pools.Very little IgG is produced during the early stages of the primaryIgG is the most abundant class of Ig in the body, constituting approximately 75% of the total immunoglobulin and distributed equally within the intravascular and extravasular pools. Very little IgG is produced during the early stages of the primary