Distribution of Lats Activity in Immunoglobulin G Subclass

Abstract

The immunological character of LATS was examined by affinity chromatography on Anti-IgG, Anti-Fab, Anti-Fc and Staphylococcal Protein A bound Sepharose. By affinity chromatography on Anti-IgG, Anti-Fab and Anti-Fc bound Sepharose, it is possible to separate LATS-immunoglobulin from LATS positive serum without loss of activity. Affinity chromatography on Protein A bound Sepharose is useful for obtaining further purified LATS-immunoglobulin. By this method, it is possible to separate I gG molecules of the subclasses IgG(1), I gG ( 2) and IgG (4) with high LATS activity. LATS activity was not found in the IgG(3) fraction.When IgG(1) fraction was purified from the fraction containing the 3 subclasses of IgG(1), IgG(2) and IgG(4), about 85 % of total protein was found in IgG(1). However, specific activity per protein of LATS in IgG (1) fraction did not change remarkably. After papain hydrolysis the thyroid stimulating activity of LATS\x=req-\ immunoglobulin was located in Fab fraction of these 3 subclasses of IgG(1), IgG(2) and IgG(4), and especially in IgG(1). The Fab fraction presents a short acting type of thyroid stimulating activity. These data indicate that LATS activity is mainly distributed in the Fab fragment of IgG(1). LATS (Long Acting Thyroid Stimulator) in serum from hyperthyroid patients has the immunological properties of polyclonal immunoglobulin G(LG) (Kriss et al. 1964;Kriss 1968;McKenzie 1967; Ochi 8c DeGroot 1968). LATS immuno¬ globulin can be purified by chromatography from LATS positive serum using DEAE or CMC-cellulose, salting out using ammonium sulphate, phosphate

Further Characterization of Thyrotropin-Displacing-Activity (TDA): Evidence of Restricted Heterogeneity

“…Similar to the results reported by Zakarija (1983) and Ochi et al (1977) we found a heterogeneous distribution of TDA in IgG-subclasses. With one exception displacing activity was maximal or enriched compared with whole IgG in peak III after Protein-A subfractionation corresponding to IgG 1 • Despite considerable contamination with other subclasses peak II (IgG 2 ) was associated with the receptor binding activity only in one case, whose IgG was highly positive for TDA in all fractions.…”

“…These findings provided evidence that thyroid stimulating antibodies are not distributed at random among IgG molecules. Ochi, Yoshimura, Takashi and Miyazaki (1977) found that LATS-activity was not evenly distributed among IgG-subclasses. To obtain further information on the oligoclonal or even monoclonal character of the antibodies involved, serum from Graves' disease patients was subfractionated, using Protein A bound Sepharose.…”

Thyroid-stimulating antibody activity between different immunoglobulin G subclasses.

“…Protein A depletion of IgG3 showed that there was no long-acting thyroid stimulator activity in this subclass (19), and pH gradient elution of protein A-bound IgG showed that the major (but not unique) component of TSH receptor binding activity resided in the IgG, plus IgG4 fraction (20). However, further fractionation was not possible using this technique.…”

Demonstration of thyroid stimulating activity within H chain fragments of TSAb‐IgG by protease digestion and reduction

“…In the present study the biological activity in 5 tested samples was equally divided between IgG (l) and IgG (k), and was also found in both Fab (k) and Fab (l) fragments. These facts suggest that TSAb-IgG in the tested cases may be polyclonal, with restricted heterogeneity (IgG 1 subclass restriction has been reported (Ochi et al, 1977)).…”