Who produces Antibodies?

UP CHO - 2018

Applied Microbiology & Infection control

Easy

Appeared in: UP CHO - 2018

Explanation

Plasma cells are the correct answer as they are terminally differentiated B-lymphocytes specialized for mass production and secretion of antibodies.
When a B-lymphocyte is activated by an antigen, it transforms into a plasma cell, which functions as an 'antibody factory'.
A single plasma cell is capable of secreting hundreds to thousands of antibody molecules per second, making it the primary source of circulating antibodies.

Option A: Lymphocytes are a broad category of white blood cells. While B-lymphocytes are the precursors to plasma cells, they are not the final, high-volume antibody-producing cells themselves.
Option B: Erythrocytes, or red blood cells, have no role in the immune response. Their primary function is to transport oxygen from the lungs to the body's tissues.
Option D: Eosinophils are a type of granulocyte involved in combating multicellular parasites and certain infections. They also play a role in allergic reactions but do not produce antibodies.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Cellular basis of humoral immunity as background academic context rather than a clinical decision trigger.
Understanding that plasma cells produce antibodies is fundamental to immunology and clinical practice. It explains the mechanism behind vaccinations, which work by stimulating B-cells to differentiate into plasma cells and memory cells, providing long-term immunity.
In diseases like Multiple Myeloma, there is a malignant proliferation of plasma cells, leading to an overproduction of a single type of (monoclonal) antibody, which can be detected in the blood and urine (Bence-Jones protein).
What if? If a patient has a primary immunodeficiency where B-cells cannot differentiate into plasma cells (e.g., Common Variable Immunodeficiency - CVID), they will have low levels of antibodies (hypogammaglobulinemia) and be susceptible to recurrent bacterial infections. Treatment involves immunoglobulin replacement therapy.

How to Approach the Question

First, identify the core question: Which cell type is responsible for making antibodies?
Recall the key players in the adaptive immune system: T-lymphocytes and B-lymphocytes.
Remember that humoral (antibody-mediated) immunity is the domain of B-lymphocytes.
Differentiate between the roles of a B-lymphocyte and a plasma cell. A B-lymphocyte recognizes an antigen, but it is the plasma cell—its differentiated form—that becomes the factory for producing and secreting antibodies.
Evaluate the options. 'Lymphocyte' is a broad term. 'Plasma cell' is the specific, terminally differentiated cell that performs the function asked in the question.
Eliminate the other options based on their known functions: Erythrocytes for oxygen transport and Eosinophils for parasitic/allergic responses. Therefore, 'Plasma cells' is the most accurate and specific answer.

Concept Tested & Keywords

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E6 Pathology- ROBBINS & COTRAN PATHOLOGIC BASIS OF DISEASE 10TH Ed p. 202-204

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E6 Harper's Illustrated Biochemistry2023 (pp 26-793 of 813) p. 654-656