       Document 0649
 DOCN  M9640649
 TI    Humoral response to oligomeric human immunodeficiency virus type 1
       envelope protein.
 DT    9604
 AU    Richardson TM Jr; Stryjewski BL; Broder CC; Hoxie JA; Mascola JR; Earl
       PL; Doms RW; Department of Pathology, University of Pennsylvania,
       Philadelphia; 19104, USA.
 SO    J Virol. 1996 Feb;70(2):753-62. Unique Identifier : AIDSLINE
       MED/96135183
 AB    The humoral immune response to human immunodeficiency virus type 1
       (HIV-1) is often studied by using monomeric or denatured envelope
       proteins (Env). However, native HIV-1 Env complexes that maintain
       quaternary structure elicit immune responses that are qualitatively
       distinct from those seen with monomeric or denatured Env. To more
       accurately assess the levels and types of antibodies elicited by HIV-1
       infection, we developed an antigen capture enzyme-linked immunosorbent
       assay using a soluble, oligomeric form of HIV-1IIIB Env (gp140) that
       contains gp120 and the gp41 ectodomain. The gp140, captured by various
       monoclonal antibodies (MAbs), retained its native oligomeric structure:
       it bound CD4 and was recognized by MAbs to conformational epitopes in
       gp120 and gp41, including oligomer-specific epitopes in gp41. We
       compared the reactivities of clade B and clade E serum samples to
       captured Env preparations and found that while both reacted equally well
       with oligomeric gp140, clade B seras reacted more strongly with
       monomeric gp120 than did clade E samples. However, these differences
       were minimized when gp120 was captured by a V3 loop MAb, which may lead
       to increased exposure of the CD4 binding site. We also measured the
       ability of serum samples to block binding of MAbs to epitopes in gp120
       and gp41. Clade B serum samples consistently blocked binding of
       oligomer-dependent MAbs to gp41 and, to a slightly lesser extent, MAbs
       to the CD4 binding site in gp120. Clade E serum samples showed
       equivalent or greater blocking of oligomer-dependent gp41 antibodies and
       considerably less blocking of CD4-binding-site MAbs. Finally, we found
       that < 5% of the antibodies in clade B sera bound to epitopes present
       only in monomeric gp120, 30% bound to epitopes present in both monomeric
       gp120 and oligomeric gp140, and 70% bound to epitopes present in
       oligomeric gp140, which includes gp41. Thus, captured oligomeric Env
       closely reflects the antigenic characteristics of Env protein on the
       surface of virions and infected cells, retains highly conserved epitopes
       that are recognized by antibodies raised against different clades, and
       makes it possible to detect a much greater fraction of total anti-HIV-1
       Env activity in sera than does native monomeric gp120.
 DE    Animal  Antibodies, Monoclonal/IMMUNOLOGY  Cell Line  Cells, Cultured
       Enzyme-Linked Immunosorbent Assay/*METHODS  Gene Products,
       env/*IMMUNOLOGY  Human  HIV Antibodies/BLOOD/*IMMUNOLOGY  HIV
       Antigens/*IMMUNOLOGY  HIV Envelope Protein gp120/IMMUNOLOGY  HIV
       Envelope Protein gp41/IMMUNOLOGY  HIV Seropositivity/BLOOD/IMMUNOLOGY
       HIV-1/*IMMUNOLOGY/ISOLATION & PURIF  Recombinant Fusion
       Proteins/IMMUNOLOGY  Support, U.S. Gov't, P.H.S.  JOURNAL ARTICLE

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

