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A new subtype of human immunodeficiency virus type 1 (MVP-5180) from Cameroon
L G Gürtler1, P H Hauser, J Eberle
1Max von Pettenkofer Institute, University of Munich, Germany.
Insights
A novel human immunodeficiency virus type 1 (HIV-1) subtype, MVP-5180, was identified in Cameroon. This divergent HIV-1 strain, subtype O, has unique genetic and serological characteristics, impacting HIV evolution and vaccine development.
Area of Science:
- Virology
- Immunology
- Genetics
Background:
- Human immunodeficiency virus type 1 (HIV-1) exhibits genetic diversity, with various subtypes circulating globally.
- Understanding the genetic and antigenic properties of different HIV-1 subtypes is crucial for effective diagnostics and vaccine design.
- Previous studies have identified distinct HIV-1 subtypes, but novel strains continue to emerge, particularly in certain geographic regions.
Purpose of the Study:
- To characterize a newly isolated human immunodeficiency virus type 1 (HIV-1) subtype, designated MVP-5180, from a patient in Cameroon.
- To investigate the genetic relatedness, serological reactivity, and unique features of MVP-5180 compared to other known HIV-1 and HIV-2 strains.
- To assess the prevalence and significance of this new subtype in the Cameroonian HIV-1-infected population.
Main Methods:
- Isolation and propagation of MVP-5180 in human T-cell and monocytic cell lines.
- Polymerase chain reaction (PCR) amplification using conventional and specific primers for HIV-1 genes (env, gag, pol).
- Serological analysis using immunoblots with anti-HIV-1 sera from different countries.
- DNA sequencing and phylogenetic analysis of MVP-5180, including V3 loop sequencing, to determine genetic relationships.
Main Results:
- MVP-5180 DNA showed limited amplification with conventional primers but was detectable with specific primers.
- Serological assays revealed differential reactivity of MVP-5180 Env proteins with sera from various regions, with strong reactions from Cameroonian sera.
- Sequence analysis indicated MVP-5180 is a distinct HIV-1 subtype (subtype O) with significant genetic divergence from other HIV-1 and HIV-2 strains, particularly in the env gene and V3 loop.
- MVP-5180 was identified in 8% of HIV-1-infected Cameroonians by serology and 7% by PCR.
Conclusions:
- MVP-5180 represents a new, highly divergent subtype (subtype O) of HIV-1, distinct from previously characterized strains.
- The unique genetic and serological profile of MVP-5180 highlights the complex evolutionary dynamics of HIV.
- Characterization of MVP-5180 is essential for understanding primate lentivirus evolution and for developing broadly effective HIV vaccines and diagnostics.
Abstract:
A new subtype (MVP-5180) of human immunodeficiency virus type 1 (HIV-1) was isolated from a Cameroonian AIDS patient. MVP-5180 was grown in several human T-cell lines and the monocytic U937 line. MVP-5180 DNA could not be amplified by nested primer PCR with conventional env primers and could be only very faintly amplified with gag and pol primers. Most German, Ivoirian, and Malawian anti-HIV-1 sera reacted faintly or moderately with Env proteins in an MVP-5180 immunoblot, whereas some Cameroonian sera reacted strongly. Of HIV-1-infected Cameroonians, 8% were identified by serological methods as infected with MVP-5180; 7% were positive when MVP-5180-specific PCR env primers were used. DNA sequence analysis of MVP-5180 showed that its genetic organization was that of HIV-1, with 65% similarity to HIV-1 and 56% similarity to HIV-2 consensus sequences. The env gene of MVP-5180 had similarities to HIV-1 and HIV-2 of 53 and of 49%, respectively. V3 loop analysis identified a crown of Gly-Pro-Met-Arg by using cloned DNA and Gly-Pro-Leu-Arg by using PCR-amplified DNA, neither of which configuration has been described for other HIV strains. In an analysis of relationships, MVP-5180 occupied a position distant to all other HIV-1 strains, including the chimpanzee simian immunodeficiency virus type 1 SIVcpz and the Uganda virus U455, and closer to the HIV-1/HIV-2 divergence node. MVP-5180, together with another Cameroonian isolate, ANT-70, constitutes a group subtype O of the most divergent HIV-1 isolates yet identified. Characterization of MVP-5180 is important for understanding the natural history of the primate immunodeficiency viruses and for the development of vaccines and diagnostics.