Natural history of HIV-1 infection

Rapid detection of the CCR2-V64I, CCR5-A59029G and SDF1-G801A polymorphisms by tetra-primer PCR

OBJECTIVE

To develop tetra-primer PCR assays for detection of the CCR2-V64I, CCR5-A59029G and SDF1-G801A polymorphisms associated with HIV pathogenesis.

DESIGN AND METHODS

For each assay, two primers for the amplification of the gene locus are combined in one tube with two primers for the subsequent allele specific amplification (ASA). In the first set of cycles, pre-amplification of the gene region of interest is ensured by the gene specific primers. In the second set of cycles, lowering the annealing temperature allows ASA on the newly produced template.

RESULTS

Analysis of 90 DNA samples resulted in allele frequencies for CCR2-V64I, CCR5-A59029G and SDF1-G801A which are similar to other Caucasian cohorts. Furthermore, re-analysis of sequenced genomic DNA by tetra-primer PCR analysis (7-11 times) always showed identical results.

CONCLUSION

Our set of single-tube assays allows rapid and reproducible genotyping of the CCR2-V64I, CCR5-A59029G and SDF1-G801A polymorphisms. These inexpensive but accurate assays are valuable for screening these polymorphisms in cohorts of HIV-infected patients.

13. HIV-1 infection

This review is intended to provide a fundamental perspective on the dynamic interplay between HIV-1 and the immune system, an essential aspect in defining the pathogenesis and treatment of AIDS. HIV-1 infection, the cause of AIDS, is a worldwide pandemic with enormous adverse heath and economic implications, particularly in the developing world. This bloodborne and sexually transmitted disease, which evolved from simian immunodeficiency virus, infects and replicates in helper T cells and macrophages and utilizes CD4 and a chemokine coreceptor for entry. Immune deficiency occurs as a result of virally induced attrition of CD4 T cells, resulting in the development of opportunistic infections and malignancy. Prophylaxis against opportunistic infections is required according to the extent of immune deficiency. HIV-specific immunity can control viral replication and delay disease progression but does not clear infection. Antiretroviral treatment consists of inhibitors that target for viral entry, reverse transcriptase, and viral protease. Therapy can control viral replication, restore immunity, and delay disease progression, but it cannot eliminate infection. Thus chronic infection persists even in treated patients. Antiretroviral drugs have been highly effective in preventing mother-to-child transmission and for postexposure prophylaxis. Several novel vaccines in development hold promise for either effective infection prevention or attenuation of disease progression.

From HIV infection to AIDS: a dynamically induced percolation transition?

The origin of the unusual incubation period distribution in the development of AIDS is largely unresolved. A key factor in understanding the observed distribution of latency periods, as well as the occurrence of infected individuals not developing AIDS at all, is the dynamics of the long-lasting struggle between HIV and the immune system. Using a computer simulation, we study the diversification of viral genomes under mutation and the selective pressure of the immune system. In non-HIV infections, vast spreading of viral genomes in genome space usually does not take place. In the case of an HIV infection, this may occur, as the virus successively weakens the immune system by the depletion of CD4+ cells. In a sequence space framework, this leads to a dynamically induced percolation transition, corresponding to the onset of AIDS. As a result, we obtain a prolonged shape of the incubation period distribution, as well as a finite fraction of non-progressors that do not develop AIDS, comparing well with results from recent clinical research.

Increased expression of the inflammatory chemokine CXC chemokine ligand 9/monokine induced by interferon-gamma in lymphoid tissues of rhesus macaques during simian immunodeficiency virus infection and acquired immunodeficiency syndrome

Chemokines are important mediators of cell trafficking during immune inductive and effector activities, and dysregulation of their expression might contribute to the pathogenesis of human immunodeficiency virus type 1 and the related simian immunodeficiency virus (SIV). To understand better the effects of SIV infection on lymphoid tissues in rhesus macaques, we examined chemokine messenger RNA (mRNA) expression patterns by using DNA filter array hybridization. Of the 34 chemokines examined, the interferon gamma (IFN-gamma)-inducible chemokine CXC chemokine ligand 9/monokine induced by interferon-gamma (CXCL9/Mig) was one of the most highly up-regulated chemokines in rhesus macaque spleen tissue early after infection with pathogenic SIV. The relative levels of expression of CXCL9/Mig mRNA in spleen and lymph nodes were significantly increased after infection with SIV in both quantitative image capture and analysis and real-time reverse transcriptase-polymerase chain reaction assays. In addition, in situ hybridization for CXCL9/Mig mRNA revealed that the patterns of expression were altered after SIV infection. Associated with the increased expression of CXCL9/Mig were increased numbers of IFN-gamma mRNA-positive cells in tissues and reduced percentages of CXC chemokine receptor (CXCR) 3(+)/CD3(+) and CXCR3(+)/CD8(+) lymphocytes in peripheral blood. We propose that SIV replication in vivo initiates IFN-gamma-driven positive-feedback loops in lymphoid tissues that disrupt the trafficking of effector T lymphocytes and lead to chronic local inflammation, thereby contributing to immunopathogenesis.