A child is suffering from recurrent chronic infections with encapsulated bacteria; Which subclass of IgG does the child has deficiency: (A) IgG1, (B) IgG2, (C) IgG3, (D) IgG4
Answer is B. * IgG has four subclasses: IgG1, IgG2, IgG3 and IgG4 * IgG2 antibody is directed against polysaccharide antigens and hence it is most impoant defence against encapsulated bacteria. Ref:- Review of medical microbiology and immunology 13th ed; pg num:- 1127