Mdp. Boyle et al., DO CHICKENS IMMUNIZED WITH BACTERIAL IMMUNOGLOBULIN G-BINDING PROTEINS PRODUCE RHEUMATOID FACTOR-LIKE ANTIBODIES, Scandinavian journal of immunology, 47(3), 1998, pp. 218-222
An association between the production of rheumatoid factor (RF)-like a
ntibodies in animals immunized with bacterial immunoglobulin (Ig)G-bin
ding proteins has been noted. Three potential explanations have been p
roposed: (1) altered host IgG due to binding of the immunogen; (2) B-c
ell superantigenic properties of the binding proteins; and (3) idiotyp
e-anti-idiotype response leading to an antibody which acts as an antig
en mimic. In order to distinguish among these possibilities, it is nec
essary to carry out studies in animals whose IgG does not react with t
he IgG-binding protein immunogen. Consequently, we have determined the
effects of immunizing chickens with a purified group C streptococcal
IgG-binding protein, FcRc, a bacterium expressing this protein, and ap
propriate control immunogens. The results of these studies provided ev
idence for production of specific antibodies to FcRc in groups of chic
kens immunized with either the pure protein or bacteria expressing the
protein. No significant association with production of RF-like antibo
dies was noted, favouring the altered IgG-binding explanation for the
association between RF-like antibodies and immunization with the bacte
rial IgG-binding proteins.