Analysis of infectious virus clones from two HIV-1 superinfection cases suggests that the primary strains have lower fitness

<p>Abstract</p> <p>Background</p> <p>Two HIV-1 positive patients, L and P, participating in the Amsterdam Cohort studies acquired an HIV-1 superinfection within half a year from their primary HIV-1 infection (Jurriaans <it>et al</it>., <it>JAIDS </it>2008, <b>47:</b>69-73). The aim of this study was to compare the replicative fitness of the primary and superinfecting HIV-1 strains of both patients. The use of isolate-specific primer sets indicated that the primary and secondary strains co-exist in plasma at all time points after the moment of superinfection.</p> <p>Results</p> <p>Biological HIV-1 clones were derived from peripheral blood CD4 + T cells at different time point, and identified as the primary or secondary virus through sequence analysis. Replication competition assays were performed with selected virus pairs in PHA/IL-2 activated peripheral blood mononuclear cells (PBMC's) and analyzed with the Heteroduplex Tracking Assay (HTA) and isolate-specific PCR amplification. In both cases, we found a replicative advantage of the secondary HIV-1 strain over the primary virus. Full-length HIV-1 genomes were sequenced to find possible explanations for the difference in replication capacity. Mutations that could negatively affect viral replication were identified in the primary infecting strains. In patient L, the primary strain has two insertions in the LTR promoter, combined with a mutation in the <it>tat </it>gene that has been associated with decreased replication capacity. The primary HIV-1 strain isolated from patient P has two mutations in the LTR that have been associated with a reduced replication rate. In a luciferase assay, only the LTR from the primary virus of patient P had lower transcriptional activity compared with the superinfecting virus.</p> <p>Conclusions</p> <p>These preliminary findings suggest the interesting scenario that superinfection occurs preferentially in patients infected with a relatively attenuated HIV-1 isolate.</p

HIV-1 Superinfection in the Antiretroviral Therapy Era: Are Seroconcordant Sexual Partners at Risk?

Acquisition of more than one strain of human immunodeficiency virus type 1 (HIV-1) has been reported to occur both during and after primary infection, but the risks and repercussions of dual and superinfection are incompletely understood. In this study, we evaluated a longitudinal cohort of chronically HIV-infected men who were sexual partners to determine if individuals acquired their partners' viral strains.Our cohort of HIV-positive men consisted of 8 couples that identified themselves as long-term sexual partners. Viral sequences were isolated from each subject and analyzed using phylogenetic methods. In addition, strain-specific PCR allowed us to search for partners' viruses present at low levels. Finally, we used computational algorithms to evaluate for recombination between partners' viral strains.All couples had at least one factor associated with increased risk for acquisition of new HIV strains during the study, including detectable plasma viral load, sexually transmitted infections, and unprotected sex. One subject was dually HIV-1 infected, but neither strain corresponded to that of his partner. Three couples' sequences formed monophyletic clusters at the entry visit, with phylogenetic analysis suggesting that one member of the couple had acquired an HIV strain from his identified partner or that both had acquired it from the same source outside their partnership. The 5 remaining couples initially displayed no evidence of dual infection, using phylogenetic analysis and strain-specific PCR. However, in 1 of these couples, further analysis revealed recombinant viral strains with segments of viral genomes in one subject that may have derived from the enrolled partner. Thus, chronically HIV-1 infected individuals may become superinfected with additional HIV strains from their seroconcordant sexual partners. In some cases, HIV-1 superinfection may become apparent when recombinant viral strains are detected

The role of neutralizing antibodies in prevention of HIV-1 infection: what can we learn from the mother-to-child transmission context?

International audienceIn most viral infections, protection through existing vaccines is linked to the presence of vaccine-induced neutralizing antibodies (NAbs). However, more than 30 years after the identification of AIDS, the design of an immunogen able to induce antibodies that would neutralize the highly diverse HIV-1 variants remains one of the most puzzling challenges of the human microbiology. The role of antibodies in protection against HIV-1 can be studied in a natural situation that is the mother-to-child transmission (MTCT) context. Indeed, at least at the end of pregnancy, maternal antibodies of the IgG class are passively transferred to the fetus protecting the neonate from new infections during the first weeks or months of life. During the last few years, strong data, presented in this review, have suggested that some NAbs might confer protection toward neonatal HIV-1 infection. In cases of transmission, it has been shown that the viral population that is transmitted from the mother to the infant is usually homogeneous, genetically restricted and resistant to the maternal HIV-1-specific antibodies. Although the breath of neutralization was not associated with protection, it has not been excluded that NAbs toward specific HIV-1 strains might be associated with a lower rate of MTCT. A better identification of the antibody specificities that could mediate protection toward MTCT of HIV-1 would provide important insights into the antibody responses that would be useful for vaccine development. The most convincing data suggesting that NAbs migh confer protection against HIV-1 infection have been obtained by experiments of passive immunization of newborn macaques with the first generation of human monoclonal broadly neutralizing antibodies (HuMoNAbs). However, these studies, which included only a few selected subtype B challenge viruses, provide data limited to protection against a very restricted number of isolates and therefore have limitations in addressing the hypervariability of HIV-1. The recent identification of highly potent second-generation cross-clade HuMoNAbs provides a new opportunity to evaluate the efficacy of passive immunization to prevent MTCT of HIV-1

The HIV-1 transmission bottleneck

It is well established that most new systemic infections of HIV-1 can be traced back to one or a limited number of founder viruses. Usually, these founders are more closely related to minor HIV-1 populations in the blood of the presumed donor than to more abundant lineages. This has led to the widely accepted idea that transmission selects for viral characteristics that facilitate crossing the mucosal barrier of the recipient’s genital tract, although the specific selective forces or advantages are not completely defined. However, there are other steps along the way to becoming a founder virus at which selection may occur. These steps include the transition from the donor’s general circulation to the genital tract compartment, survival within the transmission fluid, and establishment of a nascent stable local infection in the recipient’s genital tract. Finally, there is the possibility that important narrowing events may also occur during establishment of systemic infection. This is suggested by the surprising observation that the number of founder viruses detected after transmission in intravenous drug users is also limited. Although some of these steps may be heavily selective, others may result mostly in a stochastic narrowing of the available founder pool. Collectively, they shape the initial infection in each recipient

Attitudes of Emergency Department Staff towards the Role of Clinical Pharmacists in a Region of Saudi Arabia - A Pilot Study

Purpose: To evaluate the attitudes and perceptions of medical doctors and nurses in the Emergency Department ED towards the role of clinical pharmacists. Methods: A pilot study was conducted among the medical and paramedical staff of the ED of Public Hospital, Eastern Region, Saudi Arabia, Al-Ahsa, using a 24-item questionnaire on Doctor of Pharmacy (Pharm-D) program as well as clinical pharmacist and medical staff attitudes toward the availability and possible role of clinical pharmacist in EDs. The data analysed statistically. Results: Sixteen of the 20 respondents expressed a willingness to participate in the study. Six (37.5 %) of the respondents were doctors while the rest were nursing staff. Ten (62.5 %) of the ED staff were aware of the professional degree held by clinical pharmacists (i.e., Pharm-D), and a majority, 12 (75.0 %) had heard of a health care professional called a clinical pharmacist. While exploring medical staff attitude toward the availability of a full-time pharmacist in EDs, 13 (81.3 %) of the respondents viewed this favorably while that regarding the role of pharmacists in drug adherence and patient care was viewed less favorably. Fourteen (87.5%) disagreed with giving prescription rights to clinical pharmacists for minor ailments. Conclusion: These findings highlight the need to enhance the interaction between the medical and paramedical staff on the one hand, and the clinical pharmacist on the other. Clinical pharmacists need to be given an opportunity to prove their capabilities in direct patient care in order to facilitate the full participation of future Pharm-D graduates in direct patient care in the Saudi health care system

Crocus cancellatus

Spices are appreciated for their medicinal properties besides their use as food adjuncts to enhance the sensory quality of food. In this study, Crocus cancellatus subsp. damascenus was investigated for its antioxidant activities employing different in vitro systems. Stigma extract demonstrated a radical scavenging activity against both 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radicals with IC50 values of 34.6 and 21.6 µg/mL and a good ferric reducing ability (53.9 µM Fe(II)/g). In order to clarify the potential functional properties of this spice, the carbohydrate-hydrolysing enzymes and pancreatic lipase inhibitory properties were investigated. Crocus cancellatus subsp. damascenus extract inhibited α-amylase and α-glucosidase with IC50 values of 57.1 and 68.6 µg/mL, respectively. The bioactivity was discussed in terms of phytochemicals content. The obtained results may be of interest from a functional point of view or as food additive and to promote the revalorization of this species