Avidity of antibody and agglutinability of antibody-sensitized latex in latex agglutination test.

This paper describes the avidity of IgG antibody used for preparation of latex sensitized with IgG antibody (IgG-sensitized latex) and the agglutinability of IgG-sensitized latex in slide reversed passive latex agglutination (RPLA). Using immunodiffusion techniques, it was found that anti-canine C-reactive protein (CRP) sera from four rabbits immunized with canine CRP had the same antibody titers. However, the antibodies had different levels of avidity. When lattices were sensitized under the same condition with the IgG antibodies of different avidity levels separated from the above-mentioned antisera using Protein A and canine CRP-Sepharose 4B immunosorbent, these demonstrated different patterns of agglutinability in slide RPLA. The latex sensitized with IgG antibody of higher avidity demonstrated a stronger agglutinability.