III. THE ADAPTIVE IMMUNE SYSTEM

II. HUMORAL IMMUNITY

B. WAYS THAT ANTIBODIES HELP TO DEFEND THE BODY

8. Agglutination of Microorganisms

Fundamental Statements for this Learning Object:

1. Agglutination is mainly a function of antibodies with multiple reactive Fab sites such as IgM and IgA.
2. The Fab portion of the antibodies links microorganisms together (causes them to agglutinate) so they can be phagocytosed more effectively.

 

LEARNING OBJECTIVES FOR THIS SECTION

Humoral Immunity refers to the production of antibody molecules in response to an antigen (def). These antibody molecules circulate in the plasma of the blood and enter tissue and organs via the inflammatory response. Humoral immunity is most effective microbes or their toxins located in the extracellular spaces of the body.

Antibodies or immunoglobulins (def) are specific glycoprotein configurations produced by B-lymphocytes and plasma cells in response to a specific antigen and capable of reacting with that antigen.

The antibodies produced during humoral immunity ultimately defend the body through a variety of different means. These include:

1. Opsonization
2. MAC Cytolysis
3. Antibody-dependent Cellular Cytotoxicity (ADCC) by NK Cells
4. Neutralization of Exotoxins
5. Neutralization of Viruses
6. Preventing Bacterial Adherence to Host Cells
7. Agglutination of Microorganisms
8. Immobilization of Bacteria and Protozoans
9. Promoting an Inflammatory Response

In this section we will look at agglutination of microorganisms.

Agglutination of Microorganisms

Agglutination is mainly a function of antibodies with multiple reactive Fab sites such as IgM and IgA. The Fab portion of the antibodies links microorganisms together (causes them to agglutinate) so they can be phagocytosed more effectively (see Fig. 1).

Concept Map for Ways in which Antibodies Protect the Body

For More Information: Five Classes of Human Antibodies from Unit 6

 

• QUIZ YOURSELF ON THIS SECTION

Gary E. Kaiser, Ph.D.
Professor of Microbiology
The Community College of Baltimore County, Catonsville Campus
This work is licensed under a Creative Commons Attribution 4.0 International License.
Based on a work The Grapes of Staph at https://cwoer.ccbcmd.edu/science/microbiology/index_gos.html.