Antibody recognition of synthetic peptides mimicking immunodominant regions of HIV-1 p24 and p17 proteins.
The gag gene of HIV-1 encodes a single open reading frame of 55 kDa that contains three subdomains: the matrix domain (p17), the capsid domain (p24) and the nucleocapsid domain (p15). The p24 and p17 proteins have a predominant alpha-helical structure and perform important functions throughout the viral life-cycle. The determination of gag-specific antibodies is important because declining titers of these antibodies herald clinical deterioration. In this work we present the results obtained on immunoreactiviy of synthetic peptides that mimic immunogenic alpha-helical regions of p24 and p17. The influence on the immunoreactivity of structural modifications in native sequences, including the addition of non immunogenic side chains: AAAC- and -CAAA on both side of minimal epitopes was evaluated in indirect and competitive enzyme immunoassays. The conformational characteristcs to the peptides were analysed by circular dichroism and these results were correlated with that obtained in the immunoassays. It was shown that the reactivity of peptides mimicking short alpha-helical regions of p24 and p17 is improved by adding short non immunogenic chains on both N- and C-terminus. These modifications enhanced the immobilization of the peptides onto the solid support and allowed more accessibility to the minimal epitopes by specific antibodies, in solution.
Lottersberger
J
J
Departamento de Química Orgánica, Facultad de Bioquímica y Ciencias Biológicas-UNL, Ciudad Universitaria, C.C. 242, (3000) Santa Fe, Argentina. jlotters@fbcb.unl.edu.ar
Salvetti
J L
JL
Beltramini
L M
LM
Tonarelli
G
G
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000937:Antigen-Antibody Reactions; D002942:Circular Dichroism; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D015683:Gene Products, gag / Q000737:chemistry / Q000276:immunology*; D015483:HIV Antibodies / Q000276:immunology* / Q000302:isolation & purification; D015488:HIV Antigens / Q000737:chemistry / Q000276:immunology*; D016655:HIV Core Protein p24 / Q000737:chemistry / Q000276:immunology*; D015658:HIV Infections / Q000097:blood / Q000276:immunology; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D016056:Immunodominant Epitopes / Q000737:chemistry / Q000276:immunology; D018716:Molecular Mimicry; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000276:immunology*; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012996:Solutions; D014764:Viral Proteins / Q000737:chemistry / Q000276:immunology*; D054301:gag Gene Products, Human Immunodeficiency Virus
D015683:Gene Products, gag; D015483:HIV Antibodies; D015488:HIV Antigens; D016655:HIV Core Protein p24; D016056:Immunodominant Epitopes; D010446:Peptide Fragments; D012996:Solutions; D014764:Viral Proteins; D054301:gag Gene Products, Human Immunodeficiency Virus; C054858:p17 protein, Human Immunodeficiency Virus Type 1