IgG antibodies can negatively regulate antibody responses. When IgG anti-sheep
erythrocytes (SRBC) is administered to an animal together with SRBC, the response against
SRBC will frequently be less than 1% of the response in animals immunized with SRBC
alone. The mechanism behind this phenomenon is not fully understood. It has been
suggested that suppression is caused by masking of epitopes by IgG, thus preventing B cells
from recognizing the antigen. Other possible explanations are that IgG/antigen complexes …