<prompt> The serum concentration of which of the following human IgG subclass is maximum?IgG1IgG2IgG3IgG4  <response>: IgG comprises about 75 to 85 of total serum immunoglobulinThe four IgG subclasses are numbered in order of their level in serumIgG1 is found in greatest amounts and IgG4 the least Ref: Harrisons 18e p2036 