作者: marine0425030 时间: 2015-2-12 15:56
Envelope glycans of immunodeficiency virions are almost entirely oligomannose antigens
Katie J. Dooresa,b,1, Camille Bonomellic,1, David J. Harveyc, Snezana Vasiljevicc, Raymond A. Dwekc, Dennis R. Burtona,b, Max Crispinc, and Christopher N. Scanlanc,2
+ Author Affiliations
aDepartment of Immunology and Microbial Science and International AIDS Vaccine Initiative Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA 92037;
bThe Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard University, Boston, MA 02114; and
cOxford Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
Communicated by Richard A. Lerner, The Scripps Research Institute, La Jolla, CA, June 2, 2010 (received for review April 16, 2010)
↵1K.J.D. and C.B. contributed equally to this work.
【Abstract】The envelope spike of HIV is one of the most highly N-glycosylated structures found in nature. However, despite extensive research revealing essential functional roles in infection and immune evasion, the chemical structures of the glycans on the native viral envelope glycoprotein gp120—as opposed to recombinantly generated gp120—have not been described. Here, we report on the identity of the N-linked glycans from primary isolates of HIV-1 (clades A, B, and C) and from the simian immunodeficiency virus. MS analysis reveals a remarkably simple and highly conserved virus-specific glycan profile almost entirely devoid of medial Golgi-mediated processing. In stark contrast to recombinant gp120, which shows extensive exposure to cellular glycosylation enzymes (>70% complex type glycans), the native envelope shows barely detectable processing beyond the biosynthetic intermediate Man5GlcNAc2 (<2% complex type glycans). This oligomannose (Man5–9GlcNAc2) profile is conserved across primary isolates and geographically divergent clades but is not reflected in the current generation of gp120 antigens used for vaccine trials. In the context of vaccine design, we also note that Manα1→2Man-terminating glycans (Man6–9GlcNAc2) of the type recognized by the broadly neutralizing anti-HIV antibody 2G12 are 3-fold more abundant on the native envelope than on the recombinant monomer and are also found on isolates not neutralized by 2G12. The Manα1→2Man residues of gp120 therefore provide a vaccine target that is physically larger and antigenically more conserved than the 2G12 epitope itself. This study revises and extends our understanding of the glycan shield of HIV with implications for AIDS vaccine design.