Experimental study of antibody’s response on synthetic multimeric peptide wich potentially imitate conformational neutralizing epitope of HIV-1

Abstract

The purpose: We elaborate original synthetic peptide (NEQ)₅ wich is linear multiplication up to 15 amino acids of conformational neutralizing epitope of HIV-1 N, E, Q (asparagine, glutamate, glutamine) and investigate its immunogenicity and biological properties. Methods. Peptide was synthesized in Biopeptete Co. (US) with purity nearly 95%. This peptide was covalently bound with plant peptidoglycan Immunomax™ by SMCC (succinimidyl-4-(N-maleimidomethyl)-cyclohexan-1-carboxylat). Conjugate was purified on Zeba® Desalt Spin Columns. Female mice (CBA x C57BL)F1, 2 month old in the beginning of experiments was immunized intraperitoneally 3 times with intervals of 30 – 45 days. All manipulation with animals was done according SOP. By real-time PCR we measured transcription of TNF mRNA in peritoneal exudates cells since 0,5 h to 48 h after injection pure adjuvant. Interaction of this synthetic peptide with brain glutamate receptor was investigated in NR2-GoldDot ELISA test system (US). Interaction of anti-peptide antibodies with replicating HIV-1 was investigated in MT4 cell culture by measuring p24 in culture supernatants. Results. Pure peptide don’t induce detectable antibodies production, but conjugate “peptide-Immunomax™” induced anti-peptide antibodies production in ELISA titres 10⁵⁻⁶. Pure adjuvant induced transcription of TNF mRNA in peritoneal cells only impulsive at 6 or 8 h after i.p. injection. Peptide (NEQ)₅ don’t’t react with brain glutamate receptor in ELISA system NR2 –GoldDot. Anti-peptide serum in 1/10 dilution inhibite HIV-1/IIIB replication on nearly 90%. But the same sera in the dilution 1/20 enchanced replication of other isolate of HIV-1/899 in the same cells MT4. Conclusion. Multiepitopic synthetic peptide (NEQ)₅ can induce antibodies production if would be conjugated with adjuvant for example Immunomax™. This adjuvant per se induce transcription of primary proinflammatory cytokine TNF mRNA only impulsive at 6 or 8 h after in vivo injection. Anti-peptide antiserum inhibit replication of one isolate of HIV-1/IIIB, but enchance replication of other isolate HIV-1/899 in the same cells MT4. Such dilemma is one of the troubles in vaccine elaboration.