title: The binding affinity of double-stranded RNA motifs to HIV-1 Tat protein affects transactivation and the neutralizing capacity of anti-Tat antibodies elicited after intranasal immunization.
abstract: In this study we examined the hypothesis that the binding affinity of two double-stranded (ds) RNA motifs to HIV-1 Tat protein might affect transactivation and the type of anti-Tat immune responses. Using surface plasmon resonance technology we demonstrated the capacity of the poly(A):poly(U) (pA:pU) motif to bind with high affinity to a totally synthetic Tat protein and to inhibit more efficiently the Tat/transactivation response element (TAR) RNA interaction as compared to the poly(I):poly(C) (pI:pC) motif. Furthermore, the pA:pU motif was tenfold more effective in inhibiting Tat-driven transactivation than the pI:pC motif. Following intranasal immunization of mice, both dsRNA motifs enhanced the antibody (serum and mucosal) and cellular responses to Tat. However, only the serum samples of mice immunized with Tat + pI:pC inhibited Tat-driven transactivation. The profile of serum antibody subclasses together with the secreted cytokines by Tat-stimulated splenocyte cultures indicated that both dsRNA motifs favored the induction of a balanced Th1 and Th2 immune response. The demonstration in this study that two dsRNA motifs had a marked effect on Tat/TAR RNA interaction and on the neutralizing capacity of anti-Tat specific antibody responses highlights their potential for biological applications and the importance of selecting the appropriate motif as an adjuvant for vaccine design.
authors.affiliation: UPR 9021, Institut de Biologie Moléculaire et Cellulaire, CNRS, Strasbourg, France. H.Partidos@ibmc.u-strasbg.fr
authors.forename: Charalambos D
authors.initials: CD
authors.lastname: Partidos
authors.forename: Johan
authors.initials: J
authors.lastname: Hoebeke
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Moreau
authors.forename: Olivier
authors.initials: O
authors.lastname: Chaloin
authors.forename: Mélanie
authors.initials: M
authors.lastname: Tunis
authors.forename: Guillaume
authors.initials: G
authors.lastname: Belliard
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Briand
authors.forename: Claude
authors.initials: C
authors.lastname: Desgranges
authors.forename: Sylviane
authors.initials: S
authors.lastname: Muller
mesh_terms: D000281:Administration, Intranasal; D000818:Animals; D000918:Antibody Specificity / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015696:Gene Products, tat / Q000276:immunology / Q000378:metabolism*; D015497:HIV-1 / Q000276:immunology / Q000378:metabolism*; D007371:Interferon-gamma / Q000276:immunology; D007376:Interleukin-2 / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D012330:RNA, Double-Stranded / Q000008:administration & dosage / Q000276:immunology* / Q000378:metabolism*; D012367:RNA, Viral / Q000008:administration & dosage / Q000276:immunology / Q000378:metabolism; D020349:Surface Plasmon Resonance; D013601:T-Lymphocytes / Q000276:immunology; D015533:Transcriptional Activation; D054322:tat Gene Products, Human Immunodeficiency Virus
chemical_list: D015696:Gene Products, tat; D007376:Interleukin-2; D012330:RNA, Double-Stranded; D012367:RNA, Viral; D054322:tat Gene Products, Human Immunodeficiency Virus; D007371:Interferon-gamma