which class of immunoglobulin provides passive immunity to the newborn?
All antibodies are protein blood fractions called immune globulins. There are five classes of immunoglobulins with distinct physical and functional properties: 1. IgG is the principle immunoglobulin in human serum and accounts for approximately 80% of the total immunoglobulins in the blood. These molecules effectively penetrate extravascular spaces and readily cross the placental barrier to provide passive immunity to the newborn. 2.