Intersubtype recombinant HIV type 1 involving HIV-MAL-Like and subtype H-like sequence in four Norwegian cases

Suspected epidemiological links between three cases of human immunodeficien cy virus type 1 (HIV-1) infection were verified by the finding of a shared unique virus genotype, A probable male index case was not available for tes ting. Case 1 was a female sexual partner of the index case, Case 2 was an a dult son of case 1, Case 3 was a female sexual partner of case 2, The link to the index case was substantiated by the subsequent finding of another fe male sexual contact of the index case, harboring the same HIV-1 genotype as the three other cases. To characterize the genotype further, the complete provirus nucleotide sequence was obtained directly from blood cell DNA of c ase 3. HIV cultivated from case 3 demonstrated CCR5 dependence, an extreme slow-low phenotype, and some genotypic features not present in its directly sequenced counterpart. Most of the gag, pol, and vif genes of these viruse s clustered with one of the earliest African HIV-1 strains, MAL, previously classified as a recombinant between the subtypes A, D, and I. Most of the rest of the genome was related to subtype H, albeit with less than 90% iden tity in most regions. These viruses are the only ones shown to display exte nsive similarity with MAL in the gag-pol region and among the first HIV-1 r ecombinants described involving subtype H. We postulate that the gag-pol ge nes of MAL and these viruses are derived from a common ancestor that is not necessarily intersubtype recombinant in the pol region.