<prompt> A child is suffering from recurrent chronic infections with encapsulated bacteria; Which subclass of IgG does the child has deficiencyIgG1IgG2IgG3IgG4  <response>: 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 