Antigenic mimicry of mammalian oligomannose by a naturally occurring bacterial oligosaccharide and its implications for HIV vaccine design

Oligomannose sugars on gp120 are of significance to HIV vaccine design because of the description of the broadly neutralizing mAb 2G12 and, more recently, of the potent and broadly neutralizing ‘PGT’ series of mAbs, which bind with high affinity to clusters of oligomannose moieties on gp120. Attempts to elicit oligomannose-specific antibodies have focused mainly on immunizing with antigenic clusters of synthetic oligomannose or natural oligomannose. These strategies have had limited success, suggesting that alternative approaches are needed. Here, we present the surface lipo-oligosaccharide (LOS) of Rhizobium radiobacter Rv3 that antigenically mimics the 2G12 epitope, as one potential new avenue of exploration.