A complementary La/SSB epitope anchored to Sequential Oligopeptide Carrier regulates the anti-La/SSB response in immunized animals.
ABSTRACT Complementary peptide epitopes, derived from complementary RNA sequences, have been used for suppressing the autoimmune response in experimental autoimmune diseases as myasthenia gravis, allergic neuritis and allergic encephalomyelitis. Aiming at contributing to the development of a tool that could regulate the autoantibody production against La/SSB, which is the main target of autoantibodies in Sjogren's syndrome (SS) and systemic lupus erythematosus (SLE), the complementary epitope, cpep349-364, of the minor T/major B cell epitope of La/SSB, pep349-364, was utilized for the induction of neutralizing anti-cpep349-364 antibodies in rabbit immunizations. Complementary peptides were coupled to an artificial carrier, developed in our laboratory, in order to enhance the complementary potency of cpep349-364 and its counterpart. This carrier, named Sequential Oligopeptide Carrier, SOC(n), formed by the repeating tripeptide Lys-Aib-Gly, adopts helical conformation, which allows the anchored peptide epitopes to preserve their initial reactivity such as molecular recognition, antigenicity/immunogenicity. Our study provides proof of evidence of specific interactions between idiotypic (Id)/anti-idiotypic (anti-Id) antibodies generated in immunized animals by the sense epitope (conjugate I) of La/SSB and its complementary counterpart (conjugate II). It was also demonstrated that the Id/anti-Id association is specifically disrupted by adding either the sense epitope (conjugate I) or its complementary counterpart (conjugate II). A mutual neutralization of Id/anti-Id antibodies was observed in vivo, which implies that generation of anti-Id antibodies by immunization with the complementary La/SSB epitope could scavenge the anti-La/SSB response.
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ABSTRACT: A region of human interleukin-2 (IL-2) which was predicted to be a contact point with its receptor was used to locate a homologous region in the envelope protein of human T-lymphotropic retrovirus (HTLV-III). This homologous six amino acid peptide from the carboxy (C)-terminus of the HTLV-III envelope protein was found to inhibit the biological activity of human IL-2 in a murine spleen cell proliferation assay. When conjugated to a carrier protein, this peptide inhibited the binding of radiolabelled IL-2 to its receptor. The biological activity of the peptide was antagonized by a six amino acid peptide fragment of the IL-2 receptor which was predicted to be the contact point on the receptor that corresponded to the binding region of IL-2. The HTLV-III peptide also inhibited the binding of radiolabelled IL-2 to polyclonal anti-IL-2 antiserum. These data support the previous assignment of contact points between IL-2 and its receptor. They also suggest two possible mechanisms of immunosuppression during acquired immunodeficiency syndrome (AIDS). One involves direct competition of the envelope protein or its fragments with IL-2 for binding to the IL-2 receptor. The other involves antibodies to the envelope protein which crossreact with and neutralize IL-2.Biochemical and Biophysical Research Communications 09/1986; 139(1):367-74. · 2.41 Impact Factor
- Archives of Biochemistry and Biophysics - ARCH BIOCHEM BIOPHYS. 01/1992; 296(1):137-143.
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ABSTRACT: Myasthenia gravis (MG) and experimental autoimmune myasthenia gravis (EAMG) are caused, in part, by the production of autoantibodies against the main immunogenic region, amino acids 61-76, of the alpha chain of the acetylcholine receptor (AChR). Theoretically, induction of anti-idiotypic (Id) antibodies (Abs) should be a highly specific treatment for the disease by virtue of their potential ability to neutralize Abs to the AChR. We have tested this idea by attempting to evoke such anti-Id Abs by immunization with a peptide (termed RhCA 67-16) encoded by RNA complementary to the Torpedo AChR main immunogenic region and determining whether such treatment will prevent the development of EAMG. Immunization with RhCA 67-16, but not a control peptide termed PBM 9-1, was found to elicit the production of anti-Id Abs that blocked recognition of native Torpedo AChR by its Ab. This anti-Id Ab activity was ablated by incubation of the anti-RhCA 67-16 serum with RhCA 67-16, but PBM 9-1, prior to the assay for Ab binding to AChR. The anti-Id Ab-inducing activity of RhCA 67-16 was confirmed by the ability to produce a rat monoclonal Ab to RhCA 67-16 that showed anti-Id activity for polyclonal rat Ab reactive with AChR residues 67-76. Most importantly, RhCA 67-16 immunization also prevented the development of EAMG in Lewis rats challenged with Torpedo AChR (25% incidence versus 90% in the controls) and diminished the AChR Ab levels in animals injected with low doses of AChR. Our results suggest a therapy for MG and perhaps other autoimmune diseases through the induction of anti-Id Abs by peptide immunogens.Proceedings of the National Academy of Sciences 10/1993; 90(18):8747-51. · 9.74 Impact Factor