Immunogenicity of synthetic HIV-1 gp120 V3-loop peptide-conjugate immunogens.

A successful prophylactic human immunodeficiency virus type 1 (HIV-1) vaccine must elicit an immune response that will prevent establishment of the persistent viral infection. The only response shown to be effective in this regard is virus-neutralizing antibody directed against the viral gp120 hypervariable V3-loop region. Conjugate immunogens, containing cyclic peptides representing the V3 determinant covalently bound to a carrier protein, were capable of eliciting virus-neutralizing antibodies.

Cyclic V3-loop-related HIV-1 conjugate vaccines. Synthesis, conformation and immunological properties.

Branched undecapeptides with sequences related to the virus glycoprotein V3 domain sequences of the MN and IIIB variants of HIV-1 were synthesized and cyclized with a peptide (amide) closure to cyclic decapeptides. Two-dimensional NMR studies allowed protons for the MN variant-related cycle (L-697,250) to be assigned. Molecular modelling with distance geometry methods permitted a conformation to be identified which showed good agreement with ROESY and 2D NMR study data.

Acidic derivatives of homocysteine thiolactone: utility as anionic linkers.

Homocysteine thiolactone (2) derivatives in which the nitrogen is acylated with groups containing acidic functionalities have been synthesized. These include the succinyl (3), the carboxymethylglutaryl (4), the 3-phosphonopropionyl (7), and the 3-sulfopropionyl (8) derivatives. These thiolactones can be used to introduce a thiol functionality into proteins such as the outer membrane protein complex of Neisseria meningitidis (OMPC) allowing conjugation with electrophilic ligands.

Nicarbazin complex yields dinitrocarbanilide as ultrafine crystals with improved anticoccidial activity.

Nicarbazin, a drug used to control the protozoal disease coccidiosis in poultry, is a complex of the highly insoluble drug 4,4'-dinitrocarbanilide with 2-hydroxy-4,6-dimethylpyrimidine. The structures of this and other 4,4'-dinitrocarbanilide complexes have not been determined, but an analogous 2:1 complex of 4,4'-dinitrodiphenylamine with 1,4-diacetylpiperazine has been prepared in which the only possible bonds are hydrogen bonds between the amide carbonyls and amino hydrogens. Scanning electron microscopy revealed that micron-size crystals of nicarbazin disintegrate in water to form much smaller dinitrocarbanilide crystals.