Selectivity inIgGsubclass responsetohepatitis B vaccine ininfants borntoHBsAg-positive mothers

SUMMARY IgGsubclasses ofantibodies tothehepatitis B surface antigen (HBsAg) inserafrom40healthy infants immunized withthevaccine against hepatitis Bvirus (HBV)weredetected using an enzymelinked immunosorbent assay(ELISA) withmonoclonal antibodies. Theinfants were bornto asymptomatic HBsAg-positive mothers. Total serumIgGsubclasses werealsotested toexclude a deficiency ofcertain subclasses inthese infants buttheir distribution was theoneexpected according toage.Incontrast, IgGsubclass antibodies toHBsAgwerepredominantly IgGiandIgG4.The collected dataindicate that infants produce significantly higher levels ofIgGlandIgG4thanIgG2 andIgG3inresponsetothevaccine forHBV.TheIgG4responsetoanti-viral vaccinations is uncommon. Therole ofthatIgG4subclass isnotyetclear: evenifananaphylactic role wassuggested, no adverse reactions wereobserved invaccinated children.