Serum IgG In Mice Research Articles

Xenoantisera against a murine T cell tumor product cross-react with immunoglobulin Fab determinants.

Some murine monoclonal T lymphoma cells express a surface component that reacts with chicken antisera produced against the Fab fragment of normal mouse IgG. In the present study, we use a solid phase immunoadsorbent consisting of affinity-purified chicken anti-Fab coupled to Sepharose to isolate a product produced by the in vitro T cell line, WEHI-7.1. The affinity-purified T cell surface molecule (IgT) migrated on SDS-PAGE as a single band of approximately 65,000 daltons. The object of these studies was to produce xenoantisera against the purified T cell product cross-reactive with Ig determinants and to characterize the antisera. Rabbits immunized with this purified molecule produced antibodies that reacted with Fab fragments of polyclonal mouse IgG and with the myeloma proteins MOPC-104E and MOPC-41, as detected by enzyme-linked immunosorbent assay (ELISA). This binding was eliminated by adsorption of the antisera with normal polyclonal IgG; however, adsorption with fetuin did not significantly affect the reactivity of the antisera. Radioimmune precipitation assays revealed that the rabbit anti-IgT bound to normal murine spleen and thymus cells; this reactivity was abrogated by adsorption with insolubilized polyclonal IgG. Competition radioimmunoassays demonstrated that detergent extracts of the thymus and the spleen contained material that inhibited the precipitation of MOPC-41; nonlymphoid cells lacked such material. The rabbit anti-IgT serum blocked the binding of antigen by normal T cells; adsorption of the antiserum with polyclonal IgG-Sepharose abrogated this blocking capacity. A solid phase immunoadsorbent prepared from the IgG fraction of the rabbit anti-IgT isolated a single component from formic acid-solubilized mouse thymus. This molecule had an approximate mass of 65,000 to 70,000 daltons. The anti-IgT serum isolated surface IgM and IgD from lactoperoxidase-catalyzed radioiodinated B cells. The anti-IgT serum detected IgM and IgG in mouse serum with the use of immunoelectrophoresis. The anti-IgT immunoadsorbent isolated several components from normal mouse serum, that, when analyzed by SDS-PAGE under reducing conditions, revealed bands corresponding to mu-, gamma-, and light chains as well as components that migrated between mu- and gamma-chains, and another component with an approximate mass of 45,000 daltons. Our results with antibodies to a purified T cell product indicate that a surface component of normal T cells and certain monoclonal T cell tumor lines is serologically related to the Fab fragment of serum Ig and is implicated in the binding of antigen.

Induction of pemphigus in neonatal mice by passive transfer of IgG from patients with the disease.

We examined the role of circulating autoantibodies in the pathogenesis of pemphigus vulgaris by passively transferring IgG fractions from five patients with pemphigus vulgaris into neonatal Balb/c mice, in doses of 1.5 to 16 mg per gram of body weight per day. Cutaneous blisters and erosions with the histologic, ultrastructural, and immunofluorescence features of pemphigus occurred in 39 to 55 mice given intraperitoneal injections of IgG from patients with pemphigus and in none of 58 control mice given normal human IgG. IgG fractions with high titers of pemphigus antibodies were most effective in inducing disease, and this effect was dose dependent. Titers of circulating IgG in mouse serum closely correlated with the extent of disease induced (P less than 0.002). This study strongly supports the proposed role of pemphigus autoantibodies in the pathogenesis of pemphigus vulgaris in human beings and demonstrates that pemphigus can be passively transferred to laboratory animals.