PubMed · 3407228
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R Baumgarten. 1988. [Infectiology--status, development and problems].. https://pubmed.ncbi.nlm.nih.gov/3407228/
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Infection with the human immunodeficiency virus (HIV) leads to a decrease in CD4(+) T cells and disease progression within a decade of seroconversion. However, a small group of infected people, despite being infected by HIV for 10 or more years, remain clinically asymptomatic and have stable CD4(+) cell counts without taking antiretroviral medication. To determine why these individuals, known as long-term survivors (LTS), remain healthy, the hematological profiles, viral load and properties, HIV coreceptor genotype, and anti-HIV immune responses of these people were compared with those of individuals who have progressed to disease (Progressors) over the same time period. Unlike Progressors, LTS have a low circulating viral load and a low number of HIV-infected cells. These differences in the levels of the viral load were not associated with a dominant biologic viral phenotype, varying growth kinetics of the virus, mutation in the cellular CCR5 gene, or the presence of neutralizing antibodies. Importantly, the difference in viral load could be explained by the enhanced ability of CD8(+) cells from LTS to suppress HIV replication.
Cardiomyopathy associated with HIV-1 infection is a well-recognized complication. However, it is unknown whether direct cardiomyocyte infection is involved in the pathogenesis of the cardiomyopathy. An HIV-1-based lentiviral vector and wild-type HIV-1 were used to infect human fetal cardiac myocytes in a primary culture. Quantitative polymerase chain reaction, viral p24 antigen determination, and immunofluorescence were used to detect the synthesis of HIV-1 DNA and proteins after the infection. High-efficiency infection occurred using the HIV-1-based lentiviral vector, although no infection occurred with the wild-type HIV-1 strain. Dual-labeling immunofluorescence for HIV-1 proteins and myosin confirmed that cardiomyocytes were infected. This in vitro analysis suggests that direct myocyte infection with wild-type HIV-1 may not be involved in the pathogenesis of HIV-1 cardiomyopathy. However, HIV-1-based vectors may prove useful for ex vivo cardiovascular gene therapy.
A large collection of natural HIV-1 integrase (IN) sequences has not previously been described. We reasoned that analysis of such sequences would address whether natural variation of HIV-1 IN contributes to the pathogenesis of AIDS and might also identify amino acid residues important for IN function. Sequences encoding HIV-1 IN were amplified from cryopreserved lymphocytes or plasma obtained at different times from 10 hemophilia patients who had been observed for up to 17 years. The region of the HIV-1 genome that encodes the 288-amino acid IN protein was sequenced from a total of 102 clones; information was obtained for 99.97% of 29,478 amino acid positions. Phylogenetic analysis indicated that patient samples were unique. Interpatient nucleic acid distances ranged from 0.8% to 4.9%, highlighting the tight conservation of this genomic region. No major differences were found between DNA and RNA or between early and late time points from the same patient. Significantly, no amino acid changes that might account for the variable rate of disease progression between patients were evident. Only one amino acid substitution involved a highly conserved residue known to be important for enzymatic activity. However, several interesting amino acid substitutions were noted, including residues within the C-terminal region of the protein for which sequence comparisons between animal retroviruses have not been very informative. These results should encourage the pursuit of anti-integrase therapies, especially inasmuch as the apparent biologic constraints on the IN sequence may deter the development of drug resistance.