AEGiS-07IAC: Binding of CD4 to synthetic peptides patterned on the principal neutralizing domain of gp120.

7th International AIDS Conference

Florence, Italy — June 16-21, 1991

Binding of CD4 to synthetic peptides patterned on the principal neutralizing domain of gp120.

Int Conf AIDS 1991 Jun 16-21; 7:96 (abstract no. M.A.1016)
Autiero M, Abrescia P, Dettin M, DiBello C, Guardiola J; CNR, Naples, Italy

OBJECTIVE: Studies on the binding of gp120 and gp120- derived peptides to Sepharose 4B-linked Soluble CD4 were performed. The synthetic peptides corresponding to the PND of gp120 (aa. 308-331) are able to bind CD4 both as an immobilized recombinant molecule and as a membrane-bound antigen and the interaction is specific.

METHODS: Peptides were obtained by solid phase synthesis and purified by FPLC and HPLC. The affinity matrix was prepared incubating sCD4 with CNBr-activated Sepharose 4B. The amount of eluted peptide was determined spectrophotometrically. Competition experiments were made using mAbs in presence of [125] -I labelled G-E-3 peptide (sequence (307-330) of MN isolate).

RESULTS: The specificity of the column was studied by competition experiments using anti -CD4-mAbs. Peptides corresponding to the gp120 PND domain of different isolates specifically bind to sCD4 Sepharose 4B even if the PND region is not expected to take part in the binding of gp120 to CD4. DISCUSSION AND CONCLUSION: The differences of peptides in the interaction with CD4 bring us to these conclusions: the GPGR sequence is probably involved in the binding but the context in which the GPGR motif lies may be relevant; modification of carboxy-terminal function is likely to drastically reduce the propensity of PND peptide to assume the appropriate conformation for binding; peptides binding region is not coincident with gp120-binding site.

Keywords: AEGIS, Antigens, CD4, Peptides, Antibodies, Monoclonal, Binding Sites, Recombinant Proteins, SK&F 106528, pharmacokinetics, ICA7
910616
MA1016