Antibodies that cause pathogens to dissolve or break up are known as?

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2015

Explanation

The term 'lysin' is derived from 'lysis', which means the disintegration or rupture of a cell membrane.
Lysins are antibodies that bind to antigens on the surface of a pathogen's cell membrane.
This binding initiates a process, often involving the complement cascade, that creates pores in the membrane, causing the cell to swell and burst (lyse).
This action of dissolving or breaking up the pathogen is the defining characteristic of lysins.

Option A: Antitoxins do not act on the pathogen itself; they neutralize the harmful protein toxins that the pathogen secretes. The pathogen remains intact.
Option C: Agglutinins cause pathogens to clump together (agglutinate), not dissolve. This clumping immobilizes the pathogens and makes them a larger target for phagocytic cells.
Option D: Precipitins act on soluble (dissolved) antigens, not whole pathogens. They cause these soluble antigens to form an insoluble solid (precipitate), making them easier to clear.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Mechanisms of antibody action as background academic context rather than a clinical decision trigger.
The principle of lysis is clinically significant in transfusion medicine. A transfusion reaction occurs when a recipient's antibodies (acting as lysins) attack and destroy incompatible donor red blood cells, a process called hemolysis.
Agglutination is the basis for blood typing (ABO grouping) and diagnostic tests like the Widal test for typhoid fever.
Precipitation reactions are used in laboratory techniques like immunodiffusion and immunoelectrophoresis to detect and quantify antigens or antibodies.

How to Approach the Question

First, identify the key action described in the question stem: 'cause pathogens to dissolve or break up'.
Recognize that 'dissolve' or 'break up' in a cellular context is synonymous with the biological term 'lysis'.
Scan the options for a term related to 'lysis'. The option 'Lysins' is a direct derivative.
Briefly recall the definitions of the other terms to confirm they are incorrect. Antitoxins neutralize toxins, agglutinins clump cells, and precipitins precipitate soluble antigens.
Confirm that Lysins are the antibodies responsible for causing cell lysis, making it the correct choice.

Concept Tested & Keywords

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E6 Microbiology Essentials Sastry 4e Part 2 p. 73-75

E6 Medicine Harrison 22e Part 1 p. 1015-1017

E6 Pathology- ROBBINS & COTRAN PATHOLOGIC BASIS OF DISEASE 10TH Ed p. 354-356

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