Document 0216
 DOCN  M95B0216
 TI    Studies on the intermolecular forces involved in the antibody-antigen
       interactions, using V3 synthetic peptides and sera from HIV1
       seropositive patients.
 DT    9511
 AU    Magureanu CG; Diaconu C; Alexandrescu R; Tirdei G; Cernescu C; Stefan S.
       Nicolau Institute of Virology, Bucharest, Romania.
 SO    Rev Roum Virol. 1994 Jul-Dec;45(3-4):143-57. Unique Identifier :
       AIDSLINE MED/95345002
 AB    The nature of physical forces responsible for the antibody-antigen
       (Ab-Ag) reaction was analyzed in an original system, represented by
       synthetic peptides derived from the V3 consensus sequences of some HIV1
       subtypes gp 120 and HIV1 positive human serum. For locating antigenic
       determines, flexibility, hydrophilicity and hydrophobicity profiles of
       the V3 peptides were analysed. The hydrophilicity indicates that V3 apex
       borders are involved in the first stage of the reaction. The flexibility
       and hydrophobicity suggest that the apex of the V3 loop (GPGR/Q) is
       involved in the stabilization of the complex by hydrophobic
       interactions. Further, we followed up the influence of the dielectric
       constant and of the pH upon the forces established between Ab and Ag.
       Modifications in the dielectric constant and pH reveal a significant
       contribution of electrostatic and van der Waals forces in securing the
       intermolecular complementarity. D2O produces the highest augmentation of
       the antibody affinity for the most hydrophilic peptides, while a very
       slight one was recorded for the most hydrophobic sequence. A high
       affinity of antibodies for the peptides MN, R and Z was registered at an
       acid pH, when their His residue was protonated. On the contrary, no
       influence was recorded in the case of the peptide A, which does not
       contain any His residue.
 DE    Amino Acid Sequence  Antigen-Antibody Reactions/DRUG EFFECTS
       Deuterium/PHARMACOLOGY  Human  Hydrogen-Ion Concentration  HIV
       Antibodies/*IMMUNOLOGY  HIV Antigens/*IMMUNOLOGY  HIV Envelope Protein
       gp120/*IMMUNOLOGY  HIV Seropositivity/*IMMUNOLOGY  HIV-1/*IMMUNOLOGY
       Molecular Sequence Data  Peptide Fragments/*IMMUNOLOGY  JOURNAL ARTICLE

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