No abstract

To investigate the distribution of thyroid-stimulating antibody (TSAb) activity between IgG subclasses, sera from 11 patients with Graves disease (including the National Institute of Biological Standards and Control (NIBSC) Research Standard, long acting thyroid stimulator-B) were fractionated by chromatography on affinity columns of monoclonal IgG subclass antibodies or protein A to deplete all but a single subclass. The resulting fractions were 98% or more pure for a single subclass. In all 11 patients, TSAb activity appeared to be confined to the IgG, fraction as determined by cAMP production on addition of the fractions to the FRTL-5 rat thyroid cell line. In all of eight specimens from seven patients so tested, the whole serum activity was recovered in the IgG, fraction, after adjusting for the recovery of the isotype from the column. TSAb activity in one serum comprised both lambda and kappa light chains but was IgG1 restricted. This IgG subclass restriction was not found when the same fractions were tested for thyroglobulin, microsomal/thyroid peroxidase, or tetanus toxoid antibody activity. Together with previous results showing marked restriction of both light chain usage and isoelectric point of TSAb, these results support the idea that Graves' disease may be the result of an oligo-or possibly monoclonal response at the B cell level. (J. Clin. Invest. 1990. 86:723-727.)

No abstract

We tested the hypothesis that intramuscular immunization with a multisubunit chlamydial vaccine candidate will induce long lasting immune responses in mice. Accordingly, groups of female C57BL/6 mice were immunized intramuscularly with Vibrio cholerae ghosts (VCG) expressing the Poring B and polymorphic membrane protein-D proteins of C. trachomatis or a control antigen. Humoral and cell-mediated immune responses were evaluated following immunization and after live chlamydial infection. Immunization induced an anamnestic response characterized by chlamydial-specific IgG2a and IgA antibodies in sera and vaginal lavage as well as specific genital and splenic T cell responses. The results also revealed that the local mucosal and systemic cellular and humoral immune effectors induced in mice following immunization with the vaccine candidate are long lasting. Vaccinated mice cleared intravaginal challenge with 105 chlamydial inclusion forming units within 12 days compared to control mice, which shed up to 2×103 IFUs at this time point. Moreover, rechallenge of mice 98 days after resolution of the primary infection resulted in the recall and retention of a relatively high frequency of chlamydial-specific Th1 cells and IgG2a in the genital mucosa. These results provide the first evidence that a VCG-based multisubunit chlamydial vaccine is capable of effectively stimulating anamnestic systemic and mucosal immune responses in mice. The data support further vaccine evaluation and testing for induction of long-term protective immunity.

To delineate accurately the IgG subclass distribution of thyroid auto-antibodies, sera from nine patients with Hashimoto's thyroiditis were fractionated into IgG subclasses by complete depletion of the other IgG subclasses on affinity columns. All IgG subclass fractions contained thyroglobulin and microsomal (or thyroid peroxidase) antibody activity, although when compared to the total serum concentrations of IgG subclasses, IgG4 antibodies were overrepresented. However, in contrast to recent studies, this particular subclass never predominated--IgG4 antibody levels being exceeded by those of the IgG1 and IgG2 subclasses; it seems likely that these differences relate to varying sensitivity for different subclasses in previously used assay methods. This pattern of subclass activity differed from that of tetanus toxoid antibodies, which were found in six subjects. There was no light chain restriction within any subclass, showing that the overproduction of IgG4 thyroid antibodies is not of monoclonal origin. The functional affinity of subclasses for both thyroid antigens varied between patients, but IgG2 subclass fractions showed the highest functional affinity in the majority of samples. We also found that IgG2 subclass thyroid antibodies were ineffective in eliciting antibody-dependent cell-mediated cytotoxicity, as distinct from the other three subclasses. Our results show that thyroid antibodies are less restricted in their IgG subclass distribution and patients are less heterogeneous than previously described. Moreover, IgG2 thyroid antibodies are quantitatively important and differ in relative functional affinity and effector function from IgG1 and IgG4 thyroid antibodies.