Abstract

LOTTERSBERGER, J.; SALVETTI, J.L.; BELTRAMINI, L.M.  and  TONARELLI, G.. Antibody recognition of synthetic peptides mimicking immunodominant regions of HIV-1 p24 and p17 proteins. Rev. argent. microbiol. [online]. 2004, vol.36, n.4, pp.151-157. ISSN 0325-7541.

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 a-helical structure and perform important functions throughout thevirallife-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 a-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 enzymeimmunoassays. 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 a-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 accesibility to the minimal epitopes byspecific antibodies, in solution.

Keywords : HIV-1; capsid protein p24; matrix protein p17; dissociation constants; secondary structure; synthetic epitopes.

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