Synthesis of HIV Protective Oligo-Mannoside Immunogens

PS2 Poster session 2 Even numbers
Location (hall): 
Start/end time: 
Tuesday, July 2, 2019 - 15:45 to 17:15

Matteo Cattin1, Ralph Pantophlet1, Paul Kosma1

1Herr, Vienna, Österreich

Oligomannose glycans are among the major targets on the Gp120 component of the HIV envelope protein (Env) for broadly neutralizing antibodies (bnAbs). In 2017 our group designed and synthesized a library of oligomannose mimetics, based on the unique chemical structure of a recently identified bacterial lipooligosaccharide. For every compounds both anomers were synthetized in order to understand which compound provided the best immunoresponse. 

One of these mimetics (I) is bound avidly by members of a family of oligomannose-specific bnAbs and their putative common germline precursor when presented as a glycoconjugate1. 

Fig.1: a.Glycoconiugate I, b. and c. Structure of the glycomimetics 
The good immune response provided by the βanomer of the compound I requested a modification of all the synthetic approach in order to improve the amount of βcompound. Using the Crich β-mannosylation2 we were able to synthetize a new buildings blocks 3 with high selectivity (onlyβ-anomer has been detected). 

Fig.2: Synthesis of the building block 3
The development of the building block 4, with the introduction of a new orthogonal protective group, methyl-naphthyl group, easily cleaved by oxidative agents, enables the synthesis of two different oligomannoside, the compound Man-7 and the compound Man-9.

Fig.3: Structure of Man-7 and Man-9.

  1. Pantophlet, R.; Lu, N.; Chau, D.; Rempel, C.; Pantophlet, R.; Pantophlet, R.; Trattnig, N.; Kosma, P.; Murrell, S.; Wilson, I. A.; Murrell, S.; Wilson, I. A.; Wilson, I. A.; Wilson, I. A., Nat Commun 2017, 8 (1), 1601.
  2. Crich, D.; Smith, M., J. Am. Chem. Soc. 2001, 123 (37), 9015-9020.