The immunoglobulin found in a mother's milk is...?

DHS 2018 shift 1st

Applied Physiology

Easy

Appeared in: DHS 2018 shift 1st

Explanation

IgA is the primary antibody found in bodily secretions, including breast milk, saliva, tears, and mucus.
It is present in high concentrations in colostrum, the first milk produced after birth, providing crucial protection to the newborn.
As secretory IgA, it provides local (mucosal) immunity in the infant's gut, preventing pathogens from causing infections.
This transfer of antibodies from mother to infant via breast milk is a classic example of natural passive immunity.

Option A: IgM is the first antibody produced during an initial immune response and is primarily found in the bloodstream. Its large pentameric structure restricts it from being easily passed into secretions like breast milk.
Option C: IgE is found in very low concentrations and is primarily responsible for mediating allergic reactions (Type I hypersensitivity) and defending against parasitic worm infections. It is not the main protective antibody in breast milk.
Option D: While IgG is the most abundant immunoglobulin in the blood, it is not the primary one in breast milk. Its main role in passive immunity is transferring from mother to fetus across the placenta during pregnancy.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Types of Immunoglobulins and Passive Immunity as background academic context rather than a clinical decision trigger.
Nurses play a vital role in educating new mothers about the benefits of breastfeeding, emphasizing that colostrum ('liquid gold') is rich in IgA and provides essential protection against infections.
Understanding the role of IgA reinforces the importance of encouraging and supporting breastfeeding, especially in the first few days of life, to reduce infant morbidity and mortality from diarrheal and respiratory diseases.
What if? If a mother is unable to breastfeed, the infant will not receive secretory IgA. This makes them more vulnerable to gastrointestinal and respiratory infections. Nurses should educate parents on formula safety and signs of infection to monitor for.

How to Approach the Question

First, identify the core concepts in the question: 'immunoglobulin' and 'mother's milk'.
This is a factual recall question that requires knowledge of the different types of antibodies and their primary functions/locations.
Recall the five main classes of immunoglobulins: IgG, IgA, IgM, IgD, and IgE.
Associate each immunoglobulin with its key characteristic. Remember the mnemonic GAMED.
Specifically, link 'secretions' (like milk, saliva, tears) with the 'secretory' antibody, which is IgA.
Differentiate this from IgG (crosses the placenta), IgM (first responder in blood), and IgE (allergies) to confirm the correct answer.

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