New tuberculosis vaccine candidates that are in the development pipeline need to be studied in people with HIV, who are at high risk of acquiring Mycobacterium tuberculosis infection and tuberculosis ...disease and tend to develop less robust vaccine-induced immune responses. To address the gaps in developing tuberculosis vaccines for people with HIV, a series of symposia was held that posed six framing questions to a panel of international experts: What is the use case or rationale for developing tuberculosis vaccines? What is the landscape of tuberculosis vaccines? Which vaccine candidates should be prioritised? What are the tuberculosis vaccine trial design considerations? What is the role of immunological correlates of protection? What are the gaps in preclinical models for studying tuberculosis vaccines? The international expert panel formulated consensus statements to each of the framing questions, with the intention of informing tuberculosis vaccine development and the prioritisation of clinical trials for inclusion of people with HIV.
BACKGROUNDHerpes simplex virus type-2 (HSV-2) may heighten immune activation and increase human immunodeficiency virus 1 (HIV-1) replication, resulting in greater infectivity and faster HIV-1 disease ...progression. An 18-week randomized, placebo-controlled crossover trial of 500 mg valacyclovir twice daily in 20 antiretroviral-naive women coinfected with HSV-2 and HIV-1 was conducted and HSV-2 suppression was found to significantly reduce both HSV-2 and HIV-1 viral loads both systemically and the endocervical compartment.
METHODSTo determine the effect of HSV-2 suppression on systemic and genital mucosal inflammation, plasma specimens, and endocervical swabs were collected weekly from volunteers in the trial and cryopreserved. Plasma was assessed for concentrations of 31 cytokines and chemokines; endocervical fluid was eluted from swabs and assayed for 14 cytokines and chemokines.
RESULTSValacyclovir significantly reduced plasma CXCL10 but did not significantly alter other cytokine concentrations in either compartment.
CONCLUSIONSThese data suggest genital tract inflammation in women persists despite HSV-2 suppression, supporting the lack of effect on transmission seen in large scale efficacy trials. Alternative therapies are needed to reduce persistent mucosal inflammation that may enhance transmission of HSV-2 and HIV-1.
CD1 proteins evolved to present diverse lipid antigens to T cells. In comparison to MHC proteins, CD1 proteins exhibit minimal allelic diversity as a result of non-synonymous single nucleotide ...polymorphisms (SNPs). However, it is unknown if common SNPs in gene regulatory regions affect CD1 expression and function. We report surprising diversity in patterns of inducible CD1a expression on human dendritic cells (DCs), spanning the full range from undetectable to high density, a finding not seen with other CD1 isoforms. CD1a-deficient DCs failed to present mycobacterial lipopeptide to T cells but had no defects in endocytosis, cytokine secretion, or expression of co-stimulatory molecules after LPS treatment. We identified a SNP in the 5’ untranslated region (rs366316) that was common and strongly associated with low CD1a surface expression and mRNA levels (p=0.03 and p=0.001, respectively). Using a CD1a promoter-luciferase system in combination with mutagenesis studies, we found that the polymorphic allele reduced luciferase expression by 44% compared to the wild-type variant (p<0.001). Genetic regulation of lipid antigen presentation by varying expression on human DCs provides a mechanism for achieving population level differences in immune responses despite limited structural variation in CD1a proteins.
Profiling immunity to HIV vaccines with systems biology Andersen-Nissen, Erica; Heit, Antje; McElrath, M Juliana
Current opinion in HIV & AIDS,
2012-January, 2012-Jan, 2012-01-00, 20120101, Volume:
7, Issue:
1
Journal Article
Open access
PURPOSE OF REVIEWThe recent modest success of the RV144 HIV vaccine trial in Thailand has shown that development of an HIV vaccine is possible. Designing a vaccine that achieves better protection, ...however, will require a more complete understanding of vaccine mechanisms of action and correlates of protection. Systems biology approaches enable integration of large datasets from a variety of assays and offer new approaches to understanding how vaccine-induced immune responses are coordinately regulated. In this review, we discuss the recent advances in clinical trial design, specimen collection, and assay standardization that will generate datasets for systems analyses of immune responses to HIV vaccines.
RECENT FINDINGSSeveral recently published HIV vaccine trials have shown that different HIV vaccine prime/boost combinations can greatly affect the immune response generated, but mechanistic insights into their modes of action are lacking. Novel systems biology studies of efficacious, licensed vaccines provide a new template for analysis of HIV vaccines. To generate datasets appropriate for systems analysis, current HIV vaccine clinical trials are undergoing design modifications and increased standardization of specimen collection and immune response assays.
SUMMARYSystems biology approaches to HIV vaccine evaluation are driving new methods of HIV vaccine immune response profiling in clinical trials and will hopefully lead to new improved HIV vaccines in the near future.
Cryopreservation of peripheral blood leukocytes is widely used to preserve cells for immune response evaluations in clinical trials and offers many advantages for ease and standardization of ...immunological assessments, but detrimental effects of this process have been observed on some cell subsets, such as granulocytes, B cells, and dendritic cells. Assaying fresh leukocytes gives a more accurate picture of the in vivo state of the cells, but is often difficult to perform in the context of large clinical trials. Fresh cell assays are dependent upon volunteer commitments and timeframes and, if time-consuming, their application can be impractical due to the working hours required of laboratory personnel. In addition, when trials are conducted at multiple centers, laboratories with the resources and training necessary to perform the assays may not be located in sufficient proximity to clinical sites. To address these issues, we have developed an 11-color antibody staining panel that can be used with Trucount tubes (Becton Dickinson; San Jose, CA) to phenotype and enumerate the major leukocyte populations within the peripheral blood, yielding more robust cell-type specific information than assays such as a complete blood count (CBC) or assays with commercially-available panels designed for Trucount tubes that stain for only a few cell types. The staining procedure is simple, requires only 100 μl of fresh whole blood, and takes approximately 45 minutes, making it feasible for standard blood-processing labs to perform. It is adapted from the BD Trucount tube technical data sheet (version 8/2010). The staining antibody cocktail can be prepared in advance in bulk at a central assay laboratory and shipped to the site processing labs. Stained tubes can be fixed and frozen for shipment to the central assay laboratory for multicolor flow cytometry analysis. The data generated from this staining panel can be used to track changes in leukocyte concentrations over time in relation to intervention and could easily be further developed to assess activation states of specific cell types of interest. In this report, we demonstrate the procedure used by blood-processing lab technicians to perform staining on fresh whole blood and the steps to analyze these stained samples at a central assay laboratory supporting a multicenter clinical trial. The video details the procedure as it is performed in the context of a clinical trial blood draw in the HIV Vaccine Trials Network (HVTN).
Abstract
Understanding innate immune responses to candidate HIV vaccines will guide vaccine design. We assessed the early innate response in volunteers enrolled in HVTN 071, a trial of ...intramuscularly delivered Merck adenovirus serotype 5 (MRKAd5) gag/pol/nef- the same vaccine used in the Step trial. Samples were collected pre-vaccination and at 4-6 hours, days 1, 3, and 7 (n=11) post-vaccination or at day 1 post-vaccination (n=24). Cytokine and chemokine levels in the serum were measured by multiplex assay and cell populations were analyzed by multiparameter flow cytometry. Serum levels of IP-10, MCP-1, TNF-α, IL-6, IL-1RA, IFN-γ, and IL-10 were similar at baseline and 4-6 hours post-vaccination, showed up to 10-fold increases over baseline on day 1 post-vaccination, and returned to baseline levels by day 3. Dendritic cell concentrations increased in 4 hours; monocytes increased gradually and peaked at day 3. In contrast, T, B, and NK cell blood concentrations decreased sharply at day 1 post-vaccination, suggesting massive trafficking to the vaccination site. Moreover, PBMC gene expression analysis by microarray consistently revealed strong induction of inflammatory and antiviral genes. Together, these data demonstrate robust early immune activation after vaccination. Future studies of innate immune responses to other candidate HIV vaccines may elucidate why the vaccine used in the Step trial did not show efficacy.
Although TLR5 regulates the innate immune response to bacterial flagellin, it is unclear whether its function is essential during in vivo murine infections. To examine this question, we challenged ...Tlr5 super(-/-) mice transurethrally with Escherichia coli. At 2 days postinfection, wild-type mice exhibited increased inflammation of the bladder in comparison to Tlr5 super(-/-) mice. By day 5 postinfection, Tlr5 super(-/-) mice had significantly more bacteria in the bladders and kidneys in comparison to wild-type mice and showed increased inflammation in both organs. In addition, flagellin induced high levels of cytokine and chemokine expression in the bladder that was dependent on TLR5. Together, these data represent the first evidence that TLR5 regulates the innate immune response in the urinary tract and is essential for an effective murine in vivo immune response to an extracellular pathogen.
PDF
