Question

Which type of immunoglobulin is/are abundantly found in foetus?
A. IgE
B. IgG
C. IgM
D. IgD

Answer 1

Immunoglobulins also known as antibodies, are glycoprotein molecules produced by plasma cells (white blood cells). They act as a critical part of the immune response by specifically recognizing and binding to particular antigens, such as bacteria or viruses, and then aids in their destruction.

Complete Answer:
- There are three main types of immunoglobulins – IgG, IgA, and IgM. Out of these three only IgG is the only antibody class that significantly crosses the human placenta.
- These immunoglobulins are transferred to foetus from the maternal placenta as a newborn does not yet have a mature immune system and is often unable to produce an effective immune response.
- So, the placental transfer of maternal IgG antibodies to the fetus is an important mechanism that protects the infant while his/her humoral response (the immune response that involves transformation of B cells into plasma cells that produce and secretes antibodies to a specific antigen) is inefficient. It affords immunity to specific viral infections.

So the correct answer is option ‘B’ i.e., IgG immunoglobulins.

Note: At birth, the baby’s levels of IgG are equal to or slightly higher than those of the mother. This provides passive immunity during the first few months of life. Further, the size of IgG is small enough to cross the placental barrier. immunoglobulin G is the most common antibody. It is in blood and other body fluids and protects against bacterial and viral infections. It can take time to form after an infection or immunization.