Document 0224
 DOCN  M9650224
 TI    Cross-reactive antibodies between HIV-gp120 and platelet gpIIIa (CD61)
       in HIV-related immune thrombocytopenic purpura.
 DT    9605
 AU    Bettaieb A; Oksenhendler E; Duedari N; Bierling P; Laboratoire
       d'Immunologie Leuco-Plaquettaire, Centre de; Transfusion, Creteil,
       France.
 SO    Clin Exp Immunol. 1996 Jan;103(1):19-23. Unique Identifier : AIDSLINE
       MED/96150276
 AB    We have previously demonstrated that immune platelet destruction
       observed in an AIDS-free HIV-infected patient was associated with the
       presence of a cross-reactive antibody recognizing both HIV-glycoprotein
       (gp)120 and platelet gpIIIa (CD61). We have now investigated the
       presence of such antibodies in other HIV-infected patients, together
       with the molecular structure of the cross-reactive epitope. Platelet
       gpIIb/IIIa antibodies were characterized in sera from HIV-infected
       patients with immune thrombocytopenic purpura by means of an ELISA and a
       radio-immunoprecipitation procedure (RIP). The platelet antibodies were
       purified and tested for their ability to recognize HIV-gp. We also tried
       to characterize the antibody target epitope on HIV-gp120 using
       recombinant gp and synthetic peptides. IgG with anti-gpIIb/IIIa activity
       were detected, by means of an ELISA with purified gpIIb/IIIa, in 101/138
       (73%) sera from HIV-infected patients with immune thrombocytopenic
       purpura. The platelet antibodies were purified from 23 sera by
       absorption/elution on purified immobilized platelet gpIIb/IIIa, and
       recognition of gpIIIa was confirmed in eight cases with a RIP.
       Furthermore, the presence of a cross-reactive antibody between HIV-gp120
       and platelet gpIIIa was demonstrated in 18/18 patients (including the
       eight with a confirmed gpIIIa antibody) by the ability of the serum
       HIV-gp160/120 antibodies to bind to purified gpIIb/IIIa. The
       cross-reactive epitope was shown to be independent of the carbohydrate
       moieties of gp120, since deglycosylation of two recombinant (r)-gp120s
       did not abolish antibody binding. However, the antibody did not
       recognize synthetic gp120 peptides spanning 355 of the 516 amino acids
       of gp120, particularly the four regions exhibiting sequences of four or
       five consecutive amino acids that are identical between r-gp120 and
       gpIIIa. Our results thus support the hypothesis that the cross-reactive
       antibody recognizes the conformational structure of gp120. These results
       strongly suggest that molecular mimicry between HIV-gp120 and platelet
       gpIIIa may be important in the pathogenesis of immune thrombocytopenia
       in AIDS-free HIV-infected patients.
 DE    Antigens, CD/*IMMUNOLOGY  Autoantibodies/*BLOOD
       Carbohydrates/IMMUNOLOGY  Cross Reactions  Epitopes/IMMUNOLOGY  Human
       HIV Envelope Protein gp120/*IMMUNOLOGY  HIV Infections/BLOOD/*IMMUNOLOGY
       HIV-1/*IMMUNOLOGY  Platelet Glycoprotein GPIIb-IIIa Complex/*IMMUNOLOGY
       Platelet Membrane Glycoproteins/*IMMUNOLOGY  Purpura, Thrombocytopenic,
       Idiopathic/BLOOD/*IMMUNOLOGY  Support, Non-U.S. Gov't  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).