Conference overview: Cancer Immunotherapy and Immunomonitoring (CITIM): Moving forward

The immune system is a critical element involved in the control of tumor development and progression. While professionals have learned how to manipulate the immune system to generate tumor-specific immune responses, cancer immunotherapy has not yet delivered substantial clinical benefits. It has become increasingly clear that tumor-induced abnormalities in the immune system not only hamper tumor immunosurveillance, but also limit the efficacy of cancer immunotherapy. Meanwhile, the results of recent studies allow the belief that one is on the edge of a real breakthrough in this promising direction in cancer therapy. The 2(nd) International Conference 'Cancer Immunotherapy and Immunomonitoring (CITIM)' was the second meeting in Eastern Europe to specifically focus on the issue of immune regulation in the tumor environment, cancer immunotherapy, and immunomonitoring of immunotherapeutic clinical trials. This CITIM Conference held in Budapest, Hungary, was comprised from 12 plenary sessions, Best Abstract Award session, Poster session, and four Keynote lectures. Outstanding presentations and numerous productive discussions summarized the current place of the field and opened new directions for improving monitoring and therapy for patients with cancer.     

Health and function of participants in the Long Life Family Study: A comparison with other cohorts

Individuals from families recruited for the Long Life Family Study (LLFS) (n= 4559) were examined and compared to individuals from other cohorts to determine whether the recruitment targeting longevity resulted in a cohort of individuals with better health and function. Other cohorts with similar data included the Cardiovascular Health Study, the Framingham Heart Study, and the New England Centenarian Study. Diabetes, chronic pulmonary disease and peripheral artery disease tended to be less common in LLFS probands and offspring compared to similar aged persons in the other cohorts. Pulse pressure and triglycerides were lower, high density lipids were higher, and a perceptual speed task and gait speed were better in LLFS. Age-specific comparisons showed differences that would be consistent with a higher peak, later onset of decline or slower rate of change across age in LLFS participants. These findings suggest several priority phenotypes for inclusion in future genetic analysis to identify loci contributing to exceptional survival.     

Beta2-adrenergic receptor gene polymorphisms as systemic determinants of healthy aging in an evolutionary context

The Gln²⁷Glu polymorphism but not the Arg¹⁶Gly polymorphism of the beta2-adrenergic receptor (ADRB2) gene appears to be associated with a broad range of aging-associated phenotypes, including cancers at different sites, myocardial infarction (MI), intermittent claudication (IC), and overall/healthy longevity in the Framingham Heart Study Offspring cohort. The Gln²⁷Gln genotype increases risks of cancer, MI and IC, whereas the Glu²⁷ allele or, equivalently, the Gly¹⁶Glu²⁷ haplotype tends to be protective against these diseases. Genetic associations with longevity are of opposite nature at young-old and oldest-old ages highlighting the phenomenon of antagonistic pleiotropy. The mechanism of antagonistic pleiotropy is associated with an evolutionary-driven advantage of carriers of a derived Gln²⁷ allele at younger ages and their survival disadvantage at older ages as a result of increased risks of cancer, MI and IC. The ADRB2 gene can play an important systemic role in healthy aging in evolutionary context that warrants exploration in other populations.     

Prevalence of specific neutralizing antibodies against Sendai virus in populations from different geographic areas: implications for AIDS vaccine development using Sendai virus vectors

A Sendai virus (SeV) vector is being developed for delivery of an HIV immunogen. SeV is not known to cause disease in humans. Because it is genetically and antigenically related to human parainfluenza virus type 1 (hPIV-1), it is important to determine whether pre-existing hPIV-1 antibodies will affect immune responses elicited by a SeV vector-based vaccine. To quantify SeV neutralizing antibodies (NAb) in human serum, a sensitive virus neutralization assay was developed using a SeV vector encoding green fluorescent protein. Samples from 255 HIV-uninfected subjects from Africa, Europe, United States, and Japan, as well as from 12 confirmed hPIV-1-infected patients, were analyzed. SeV NAb titers did not vary significantly after serum was treated with receptor-destroying enzyme, indicating that non-specific hemagglutination inhibitors did not affect the assay sensitivity. A significant correlation was observed between hPIV-1 ELISA and SeV NAb titers. SeV NAb were detected in 92.5% subjects with a median titer of 60.6 and values ranging from 5.9- 11,324. The majority had titers < 1000 with 71.7% < 100 (< 5 considered negative). There was no significant difference in titer or prevalence by gender, age range or geographic origin. However, African males had a lower titer than non-Africans of either gender (p=0.007). Overall, the prevalence of SeV NAb is high and likely due to neutralization by cross-reactive hPIV-1 antibodies. Clinical trials will be needed to assess the influence of pre-existing SeV NAb on HIV-specific immune responses elicited by a SeV vaccine vector expressing HIV.     

Investigating the utility of the HIV-1 BED capture enzyme immunoassay using cross-sectional and longitudinal seroconverter specimens from Africa

BACKGROUND: The identification of populations at risk of HIV infection is a priority for trials of preventive technologies, including HIV vaccines. To quantify incidence traditionally requires laborious and expensive prospective studies. METHODS: The BED IgG-Capture enzyme immunoassay (EIA) was developed to estimate HIV-1 incidence using cross-sectional data by measuring increasing levels of HIV-specific IgG as a proportion of total IgG. To evaluate this assay, we tested 189 seroconversion samples taken at 3-monthly intervals from 15 Rwandan and 26 Zambian volunteers with known time of infection and cross-sectional specimens from 617 Kenyan and Ugandan volunteers with prevalent infection. RESULTS: The BED-EIA-estimated incidence in Uganda was unexpectedly high, at 6.1%/year [95% confidence interval (CI) 4.2-8.0] in Masaka and 6.0%/year (95% CI 4.3-7.7) in Kakira. Prospective incidence data in Masaka from the same population was 1.7%/year before and 1.4%/year after the study. Kenyan estimates were 3.5%/year in Kilifi (95% CI 2.1-4.9) and 3.4%/year in Nairobi (95% CI 1.5-5.3). From the Rwandan and Zambian data, the sensitivity of the assay was 81.2% and the specificity was 67.8%. After approximately one year, subjects misclassified as recently infected tended to have lower plasma viral loads compared with those not misclassified as recent (median copies/ml 14 773 versus 93 560; P = 0.02). Clinical presentation, sex and HIV subtype were not significantly associated with BED-EIA misclassification in seroconverter samples. CONCLUSION: These data suggest that this assay does not perform reliably in all populations. Further research is warranted before using this assay to estimate incidence from prevalent HIV samples.     

Synthesis of stable and potent delta/mu opioid peptides: analogues of H-Tyr-c[D-Cys-Gly-Phe-D-Cys]-OH by ring-closing metathesis

Ring-closing metathesis has emerged as a powerful tool in organic synthesis for generating cyclic structures via C-C double bond formation. Recently, it has been successfully used in peptide chemistry for obtaining cyclic molecules bridged through an olefin unit in place of the usual disulfide bond. Here, we describe this approach for obtaining cyclic olefin bridged analogues of H-Tyr-c[D-Cys-Gly-Phe-Cys]-OH. The synthesis of the new ligands was performed using the second generation Grubbs' catalyst. The resulting cis-8 (cDADAE) and trans-9 (tDADAE) were fully characterized and tested at delta, mu, and kappa opioid receptors. Also the linear precursor 13 (lDADAE) and the hydrogenated derivative 11 (rDADAE) also were tested. All the cyclic products containing a olefinic bond are slightly selective but highly active and potent for the delta and mu opioid receptors. Activity toward the kappa opioid receptors was absent or very low.     

Visualizing hidden heterogeneity in isogenic populations of C. elegans

Age-specific mortality levels off at advanced ages in many species; one explanation for this phenomenon is provided by the population heterogeneity theory. Although mortality at advanced ages can be well fit by heterogeneity models, population heterogeneity remains theoretical, lacking much direct evidence to support the existence of unobserved heterogeneity. Here, we provide direct evidence to support the heterogeneity theory by using isogenic population of worms of Caenorhabditis elegans. We measure the ability of individual worms to respond to a heat stress using an HSP-16.2 promoter that has been attached to GFP, a fluorescent marker that can be assessed in living animals. Worms differ substantially in their response; worms with high response have a long lifespan, and worms with low response to stress have a short life. Each of these classes results from a mix of two distinct, heterogeneous classes of worms and the addition of more classes does not result in a better fit.