Screening of HIV-1 isolates by Reverse heteroduplex mobility assay and identification of non-B subtypes in Italy

Luigi Buonaguro, Maria Tagliamonte, Maria Lina Tornesello, Elisabetta Pilotti, Claudio Casoli, Adriano Lazzarin, Giuseppe Tambussi, Massimo Ciccozzi, Giovanni Rezza, Franco M. Buonaguro

Research output: Contribution to journalArticlepeer-review


Objective: The increasing prevalence of HIV-1 transmission through heterosexual contacts and the growing number of immigrants from non-Western countries, where non-B subtypes and recombinant forms are prevalent, suggest the possible emergence in Italy of a new epidemic wave of HIV-1 non-B subtypes as well as recombinant forms. Methods: The distribution of HIV-1 subtypes has been evaluated in 63 seropositive individuals residing in Italy, most of whom were infected through a sexual route during the last 5 years. A modified heteroduplex mobility assay (HMA) strategy, reverse HMA (rHMA), has been developed in our laboratory, allowing rapid identification of divergent-from-B-subtype isolates, which have been subsequently characterized by detailed molecular and phylogenetic analyses. Results: Five samples show, on rHMA, an electrophoretic pattern compatible with a non-B subtype classification. Their phylogenetic analysis, performed on both env and gag regions, confirms the rHMA subtyping prediction, given that 3 samples fall into the "A-family" subtype and 2 into the G subtype. The 5 non-B-subtype HIV-1 isolates have been identified among 23 variants (prevalence, 21.74%) isolated during the 2000 to 2001 period in heterosexuals. In parallel, B-subtype isolates show high levels of intrasubtype nucleotide divergence, compatible with a constant HIV-1 molecular diversification. Conclusion: The Italian HIV-1 epidemic is still mostly attributable to the B subtype, which shows an increasing nucleotide heterogeneity. Heterosexual transmission and the interracial blending, however, are slowly introducing novel HIV-1 subtypes, and the data indicate that rHMA represents a powerful tool for HIV-1 biomolecular screening in epidemics characterized by a mono-/dual-subtype predominance.

Original languageEnglish
Pages (from-to)1295-1306
Number of pages12
JournalJournal of Acquired Immune Deficiency Syndromes
Issue number2
Publication statusPublished - Oct 1 2004


  • Env
  • Gag
  • Italy
  • Non-B HIV-1 subtypes
  • Reverse heteroduplex mobility assay
  • Sexual transmission

ASJC Scopus subject areas

  • Virology
  • Immunology


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