Wikipedia
Blocking antibody
A blocking antibody is an antibody that does not have a reaction when combined with an antigen, but prevents other antibodies from combining with that antigen. This function of blocking antibodies has had a variety of clinical and experimental uses.
The term can also be used for inhibiting antibody, prozone phenomenon and, agglutination reaction.
Blocking antibodies have been described as a mechanism for HSV-1 to evade the immune system.