The earliest immunoglobulin to be synthesized by the fetus is -
Option 1, 3, 4 IgM: IgM is the first immunoglobulin to be synthesized by a neonate in about 20 weeks of age. IgM is not transpoed across the placenta; hence, the presence of IgM in the fetus or newborn indicates intrauterine infection. The first immunoglobulin produced in response to an antigen is IgM. after 3 monts of bih class switching is staed and then other class of immunoglobulins are synthesised. IgM is secreted as a pentamer and is composed of five H2L2 units (similar to one IgG unit) and one moleculeof a J chain.. It is the most efficient Because its interaction with antigen can involve all 10 binding sites, it has the highest binding capacity and cross-linking of all the immunoglobulins. Option 2 IgG is the only immunoglobulin class to cross the placenta and therefore is the most abundant immunoglobulinin newborns.( this is not the the first to be synthesised in newborn)
IgA
IgG
IgE
IgM
Immunology Pa 1 (Immune Response, Antigen-Antibody Reactions, Hypersensitivity, Structure of Immune System, Immunodeficiency Disorders)