• The Journal of Korean Society of Virology
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• v.26 no.2
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• pp.251-258
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• 1996

The V3 loop, a hypervariable domain of envelope glycoprotein, has an essential role in viral infectivity and has a major epitope for type-specific neutralizing antibody. In order to investigate genetic diversity of V3 region of gp120 of human immunodeficiency virus type 1 (HIV-1) isolated from Korean patients, DNA sequences encoding the C2 to V3 region were amplified by nested polymerase chain reaction (PCR) from uncultured peripheral blood mononuclear cells obtained from 15 HIV-1 seropositive patients and nucleotide sequences were determined. All nucleotide sequences from fifteen patients were compared with 8 distinctive subtypes (A-H) and another subtype O. Phylogenetic analysis was carried out with PHYLIP ver 3.5 (Dnapars) program. Of the 15 isolates, 14 HIV-1 subjects were clustered with subtype B, while one was clustered with subtype C. Intra-subtype B distance at the nucleotide and deduced amino acid level were maximum 17.7% and 37.0%, respectively. Intra-patient distance at the nucleotide and deduced amino acid level were maximum 7.3% and 17.8%, respectively. Analysis of the nucleotide sequences revealed that Korean types have relatively well conserved sequences. These findings could be useful for assessing the source of infection and developing an AIDS vaccine.

• BMB Reports
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• v.32 no.5
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• pp.461-467
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• 1999

Recombinant Mycobacterium smegmatis expressing ovalbumin was used to immunize C57BL/6(H-$2^b$) mice, and the humoral immunity against recombinant ovalbumin was analyzed. Antibodies were purified by denatured ovalbumin-conjugated affinity chromatography. The epitopes of the antibodies were screened with a random peptide library displayed on the tip of fUSE5 filamentous phage pIII minor coat proteins. Two peptides, IRLADR and SPGAEV, were selected predominantly by the recognition of purified antibodies using biopanning methods. The composition of the peptide sequence with the primary structure of OVA revealed that the peptide sequence analogizes to INEAGR, part of the $^{323}ISQAVHAAHAEINEAGR^{339}$ sequence previously reported as the antigenic determinant for murine Band also Th cell epitopes (I-$A^d$ binding). Also, the structures of these mimotopes obtained from restrained molecular dynamic computations resulted in the formation of a $\beta$-turn proven to be a secondary structure of the parent peptide within the ovalbumin molecule, enabling us to confirm the structural similarity. This study demonstrates that immunization with recombinant M. smegmatis can generate neutralizing antibodies identical with those induced by the administration of natural antigenic proteins and supports the potential use of mycobacteria as vaccine delivery vehicles.