Second Stage (Agglutination)

Once antibody has sensitized the red cell, agglutination may or may not occur. Factors that affect this stage are:

1. Antigen-Antibody Concentration

2. Antibody Size

3. Number of Antigen Combining Sites on the Antibody

4. Number of Antigenic Sites on the Red Cell

5. Location of Antigenic Sites on the Membrane

6. Zeta Potential

Note: Other workers believe that a water-lipid interface at the red cell membrane creates a surface tension; according to this theory, agglutination of red cells by IgG antibody is facilitated when this surface tension is lowered.

Second Stage (Agglutination)