Development of mesothelioma-specific oncolytic immunotherapy enabled by immunopeptidomics of murine and human mesothelioma tumors

Malignant pleural mesothelioma (MPM) is an aggressive tumor with a poor prognosis. As the available therapeutic options show a lack of efficacy, novel therapeutic strategies are urgently needed. Given its T-cell infiltration, we hypothesized that MPM is a suitable target for therapeutic cancer vaccination. To date, research on mesothelioma has focused on the identification of molecular signatures to better classify and characterize the disease, and little is known about therapeutic targets that engage cytotoxic (CD8+) T cells. In this study we investigate the immunopeptidomic antigen-presented landscape of MPM in both murine (AB12 cell line) and human cell lines (H28, MSTO-211H, H2452, and JL1), as well as in patients' primary tumors. Applying state-of-the-art immuno-affinity purification methodologies, we identify MHC I-restricted peptides presented on the surface of malignant cells. We characterize in vitro the immunogenicity profile of the eluted peptides using T cells from human healthy donors and cancer patients. Furthermore, we use the most promising peptides to formulate an oncolytic virus-based precision immunotherapy (PeptiCRAd) and test its efficacy in a mouse model of mesothelioma in female mice. Overall, we demonstrate that the use of immunopeptidomic analysis in combination with oncolytic immunotherapy represents a feasible and effective strategy to tackle untreatable tumors.

Infant Feeding, Gut Permeability, and Gut Inflammation Markers

OBJECTIVES

Increased gut permeability and gut inflammation have been linked to the development of type 1 diabetes. Little is known on whether and how intake of different foods is linked to these mechanisms in infancy. We investigated whether the amount of breast milk and intake of other foods are associated with gut inflammation marker concentrations and permeability.

METHODS

Seventy-three infants were followed from birth to 12 months of age. Their diet was assessed with structured questionnaires and 3-day weighed food records at the age of 3, 6, 9, and 12 months. Gut permeability was assessed with the lactulose/mannitol test and fecal calprotectin and human β-defensin-2 (HBD-2) concentrations were analyzed from stool samples at the age of 3, 6, 9, and 12 months. The associations between foods and gut inflammation marker concentrations and permeability were analyzed using generalized estimating equations.

RESULTS

Gut permeability and gut inflammation marker concentrations decreased during the first year of life. Intake of hydrolyzed infant formula ( P = 0.003) and intake of fruits and juices ( P = 0.001) were associated with lower intestinal permeability. Intake of fruits and juices ( P < 0.001), vegetables ( P < 0.001), and oats ( P = 0.003) were associated with lower concentrations of HBD-2. Higher intake of breast milk was associated with higher fecal calprotectin concentrations ( P < 0.001), while intake of fruits and juices ( P < 0.001), vegetables ( P < 0.001), and potatoes ( P = 0.007) were associated with lower calprotectin concentrations.

CONCLUSIONS

Higher intake of breast milk may contribute to higher calprotectin concentration, whereas several complementary foods may decrease gut permeability and concentrations of calprotectin and HBD-2 in infant gut.

Mobile genetic elements from the maternal microbiome shape infant gut microbial assembly and metabolism

The perinatal period represents a critical window for cognitive and immune system development, promoted by maternal and infant gut microbiomes and their metabolites. Here, we tracked the co-development of microbiomes and metabolomes from late pregnancy to 1 year of age using longitudinal multi-omics data from a cohort of 70 mother-infant dyads. We discovered large-scale mother-to-infant interspecies transfer of mobile genetic elements, frequently involving genes associated with diet-related adaptations. Infant gut metabolomes were less diverse than maternal but featured hundreds of unique metabolites and microbe-metabolite associations not detected in mothers. Metabolomes and serum cytokine signatures of infants who received regular-but not extensively hydrolyzed-formula were distinct from those of exclusively breastfed infants. Taken together, our integrative analysis expands the concept of vertical transmission of the gut microbiome and provides original insights into the development of maternal and infant microbiomes and metabolomes during late pregnancy and early life.

Dysregulation of secondary bile acid metabolism precedes islet autoimmunity and type 1 diabetes

The gut microbiota is crucial in the regulation of bile acid (BA) metabolism. However, not much is known about the regulation of BAs during progression to type 1 diabetes (T1D). Here, we analyzed serum and stool BAs in longitudinal samples collected at 3, 6, 12, 18, 24, and 36 months of age from children who developed a single islet autoantibody (AAb) (P1Ab; n = 23) or multiple islet AAbs (P2Ab; n = 13) and controls (CTRs; n = 38) who remained AAb negative. We also analyzed the stool microbiome in a subgroup of these children. Factor analysis showed that age had the strongest impact on both BA and microbiome profiles. We found that at an early age, systemic BAs and microbial secondary BA pathways were altered in the P2Ab group compared with the P1Ab and CTR groups. Our findings thus suggest that dysregulated BA metabolism in early life may contribute to the risk and pathogenesis of T1D.

Associations Between Serum Fatty Acids and Immunological Markers in Children Developing Islet Autoimmunity-The TRIGR Nested Case-Control Study

Aims

Altered immune functions as well as fatty acid intake and status have been associated with the development of type 1 diabetes. We aimed to study the relationship between fatty acids and immunological markers in young children with increased genetic risk for type 1 diabetes in order to define putative mechanisms related to development of islet autoimmunity.

Methods

Serum samples for fatty acid and immunological marker measurements were obtained in the Trial to Reduce IDDM in the Genetically at Risk (TRIGR) ancillary study (Divia) from children born between 2002 and 2007 in 15 countries. Case children (n = 95) were defined as having repeated positivity for at least two out of four diabetes-associated autoantibodies. For each case child, control children were selected matched for country and date of birth (n = 173). Serum fatty acids and immunological markers were measured from cord serum and at the age of 6 and 12 months. Spearman correlation coefficients were calculated between fatty acids and immunological markers.

Results

Correlations between circulating fatty acids and immunological markers were different in case children who developed islet autoimmunity than in control children already at birth continuing across the first year of life. In case children, saturated fatty acids (SFAs) showed stronger correlations with immunological markers, while in controls, polyunsaturated fatty acids (PUFAs) showed stronger correlations.

Conclusions

In cases, SFAs were associated with several immunological markers (CXCL10, IL-6, IL-9, IL-17, and CM-CSF) previously linked to the type 1 diabetes disease process. Findings indicate that fatty acids could have immunomodulatory potential in the early phase of the disease development, although causality between fatty acids and the immunological pathways remains to be explored.

Trial registry number

NCT00179777.

Breastfeeding and circulating immunological markers during the first 3 years of life: the DIABIMMUNE study

AIMS/HYPOTHESIS

Our aim was to study the association between duration of breastfeeding and circulating immunological markers during the first 3 years of life in children with HLA-conferred susceptibility to type 1 diabetes.

METHODS

We performed a longitudinal analysis of 38 circulating immunological markers (cytokines, chemokines and growth factors) in serum samples from Finnish (56 individuals, 147 samples), Estonian (56 individuals 148 samples) and Russian Karelian children (62 individuals, 149 samples) at 3, 6, 12, 18, 24 and 36 months of age. We also analysed gut inflammation markers (calprotectin and human β defensin-2) at 3 (n = 96) and 6 months (n = 153) of age. Comparisons of immunological marker medians were performed between children who were breastfed for 6 months or longer vs children who were breastfed for less than 6 months.

RESULTS

Breastfeeding for 6 months or longer vs less than 6 months was associated with lower median of serum immunological markers at 6 months (granulocyte-macrophage colony-stimulating factor [GMCSF], macrophage inflammatory protein [MIP-3α]), 12 months (IFN-α2, vascular endothelial growth factor, GMCSF, IFN-γ, IL-21), 18 months (FGF-2, IFN-α2) and 24 months of age (CCL11 [eotaxin], monocyte chemoattractant protein-1, TGFα, soluble CD40 ligand, IL-13, IL-21, IL-5, MIP-1α) (all p < 0.01) but not at 36 months of age. Breastfeeding was not associated with gut inflammation markers at 3 and 6 months of age.

CONCLUSIONS/INTERPRETATION

Children who were breastfed for 6 months or longer had lower medians for 14 immunological markers at one or more age points during the first 2 years of life compared with children who were breastfed for less than 6 months. The clinical meaning of the findings is not clear. However, the present study contributes to the understanding of immunological differences in children that have been breastfed longer, and thus provides a mechanistic suggestion for the previously observed associations between breastfeeding and risk of type 1 diabetes.

Higher circulating EGF levels associate with a decreased risk of IgE sensitization in young children

BACKGROUND

Decreased exposure to microbial agents in industrialized countries and urban living areas is considered as a risk factor of developing immune-mediated diseases, such as allergies and asthma. Epithelial surfaces in the gastrointestinal and respiratory tracts and in the skin constitute the primary areas in contact with the environmental microbial load.

METHODS

We analyzed the levels of 30 cytokines and growth factors in serum or plasma as markers of the immune maturation in the participants in the DIABIMMUNE study from Russian Karelia (n = 60), Estonia (n = 83) and Finland (n = 89), three neighboring countries with remarkable differences in the incidences of allergies, asthma and autoimmune diseases.

RESULTS

We observed an upregulation of T helper cell signature cytokines during the first 12 months of life, reflecting natural development of adaptive immune responses. During the first years of life, circulating concentrations of epidermal growth factor (EGF) were significantly higher, especially in Russian children compared with Finnish children. The children who developed IgE sensitization showed lower levels of EGF than those without such responses.

CONCLUSION

Our results suggest that low circulating EGF levels associate with the risk of allergies possibly via the effects on the epithelial integrity and mucosal homeostasis.

Exposure to per- and polyfluoroalkyl substances associates with an altered lipid composition of breast milk

The composition of human breast milk is highly variable inter- and intra-individually. Environmental factors are suspected to contribute to such compositional variation, however, their impact on breast milk composition is currently poorly understood. We sought to (1) define the impact of maternal exposure to per- and polyfluoroalkyl substances (PFAS) on lipid composition of human breast milk, and (2) to study the combined impact of maternal PFAS exposure and breast milk lipid composition on the growth of the infants.In a mother-infant study (n = 44) we measured the levels of PFAS and lipids in maternal serum and conducted lipidomics analysis of breast milk collect 2-4 days after the delivery and at 3 months of infant age, by using ultra high performance liquid chromatography combined with quadrupole-time-of-flight mass spectrometry. Gastrointestinal biomarkers fecal calprotectin and human beta defensin 2 were measured in the stool samples at the age of 3, 6, 9, and 12 months. Maternal diet was studied by a validated food frequency questionnaire. PFAS levels were inversely associated with total lipid levels in the breast milk collected after the delivery. In the high exposure group, the ratio of acylated saturated and polyunsaturated fatty acids in triacylglycerols was increased. Moreover, high exposure to PFAS associated with the altered phospholipid composition, which was indicative of unfavorable increase in the size of milk fat globules. These changes in the milk lipid composition were further associated with slower infant growth and with elevated intestinal inflammatory markers. Our data suggest that the maternal exposure to PFAS impacts the nutritional quality of the breast milk, which, in turn, may have detrimental impact on the health and growth of the children later in life.

Effect of Early Feeding on Intestinal Permeability and Inflammation Markers in Infants with Genetic Susceptibility to Type 1 Diabetes: A Randomized Clinical Trial

OBJECTIVES

To assess whether weaning to an extensively hydrolyzed formula (EHF) decreases gut permeability and/or markers of intestinal inflammation in infants with HLA-conferred diabetes susceptibility, when compared with conventional formula.

STUDY DESIGN

By analyzing 1468 expecting biological parent pairs for HLA-conferred susceptibility for type 1 diabetes, 465 couples (32 %) potentially eligible for the study were identified. After further parental consent, 332 babies to be born were randomized at 35th gestational week. HLA genotyping was performed at birth in 309 infants. Out of 87 eligible children, 73 infants participated in the intervention study: 33 in the EHF group and 40 in the control group. Clinical visits took place at 3, 6, 9, and 12 months of age. The infants were provided either EHF or conventional formula whenever breastfeeding was not available or additional feeding was required over the first 9 months of life. The main outcome was the lactulose to mannitol ratio (L/M ratio) at 9 months. The secondary outcomes were L/M ratio at 3, 6, and 12 months of age, and fecal calprotectin and human beta-defensin 2 (HBD-2) levels at each visit.

RESULTS

Compared with controls, the median L/M ratio was lower in the EHF group at 9 months (.006 vs .028; P = .005). Otherwise, the levels of intestinal permeability, fecal calprotectin, and HBD-2 were comparable between the two groups, although slight differences in the age-related dynamics of these markers were observed.

CONCLUSIONS

It is possible to decrease intestinal permeability in infancy through weaning to an extensively hydrolyzed formula. This may reduce the early exposure to dietary antigens.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT01735123.

Serum fatty acids and risk of developing islet autoimmunity: A nested case-control study within the TRIGR birth cohort

BACKGROUND

Circulating fatty acids have been linked to development of type 1 diabetes.

OBJECTIVES

To study the prospective associations of serum fatty acids with the risk of islet autoimmunity in high-risk children.

METHODS

A nested case-control selection was carried out within the TRIGR cohort, which included infants with HLA (DQB1 or DQA1)-conferred disease susceptibility and a first-degree relative with type 1 diabetes, born between 2002 and 2007 in 15 countries and followed-up until 2017. The present study included 244 case children positive for at least two islet autoantibodies (ICA, IAA, GADA, and IA-2A) and two control children were matched for country and age. Proportions of 26 serum fatty acids at cord blood and at 6, 12, and 18 months of age were assessed using gas-chromatography.

RESULTS

The average proportions of the following fatty acids were associated with an increased risk of islet autoimmunity, adjusted for sex, HLA risk, and maternal type 1 diabetes: pentadecanoic acid (15:0) (OR 3.41: 95% CI 1.70, 6.85), heptadecanoic acid (iso 17:0) (2.64: 1.62, 4.28) and (anteiso 17:0) (2.27: 1.39, 3.70), stearic acid (18:0) (23.8: 2.32, 244.6), and conjugated linoleic acid (18:2n-7) (2.60: 1.47, 4.59). Breastfeeding and not having maternal type 1 diabetes were positively associated with levels of the above-mentioned fatty acids. N-3 fatty acids were not consistently associated with islet autoimmunity.

CONCLUSIONS

We found direct associations of pentadecanoic acid, heptadecanoic acid, stearic acid, and conjugated linoleic acid with the risk of islet autoimmunity. Further studies are needed to understand the complex role of fatty acids in the development of type 1 diabetes.

Peripheral metabolic state and immune system in first-episode psychosis - A gene expression study with a prospective one-year follow-up

he excess availability of glucose and lipids can also have an impact on the dynamics of activation and regulation of peripheral immune cellsWe aimed at understanding the correlations between peripheral metabolic state and immune system during the first year in first-episode psychosis (FEP). Patients with FEP (n = 67) and matched controls (n = 38), aged 18-40 years, were met at baseline, 2 and 12 months. Fasting peripheral blood samples were collected. We applied the NanoString nCounter in-solution hybridization technology to determine gene expression levels of 178 candidate genes reflecting activation of the immune system. Serum triglycerides, high-density lipoprotein (HDL), low-density lipoprotein (LDL) cholesterol and insulin and plasma glucose (fP-Gluc) were measured. We applied Ingenuity Pathway Analysis (IPA) to visualize enrichment of genes to functional classes. Strength of positive or negative regulation of the disease and functional pathways was deduced from IPA activation Z-score at the three evaluation points. We correlated gene expression with plasma glucose, triglycerids and HDL and LDL, and used hierarchical clustering of the pairwise correlations to identify groups of genes with similar correlation patterns with metabolic markers. In patients, initially, genes associated with the innate immune system response pathways were upregulated, which decreased by 12 months. Furthermore, genes associated with apoptosis and T cell death were downregulated, and genes associated with lipid metabolism were increasingly downregulated by 12 months. The immune activation was thus an acute phase during illness onset. At baseline, after controlling for multiple testing, 31/178 genes correlated positively with fasting glucose levels, and 54/178 genes negatively with triglycerides in patients only. The gene clusters showed patterns of correlations with metabolic markers over time. The results suggest a functional link between peripheral immune system and metabolic state in FEP. Metabolic factors may have had an influence on the initial activation of the innate immune system. Future work is necessary to understand the role of metabolic state in the regulation of immune response in the early phases of psychosis.

The Safety and Efficacy of Live Viral Vaccines in Patients With Cartilage-Hair Hypoplasia

Background

Live viral vaccines are generally contraindicated in patients with combined immunodeficiency including cartilage-hair hypoplasia (CHH); however, they may be tolerated in milder syndromes. We evaluated the safety and efficacy of live viral vaccines in patients with CHH.

Methods

We analyzed hospital and immunization records of 104 patients with CHH and measured serum antibodies to measles, mumps, rubella, and varicella zoster virus (VZV) in all patients who agreed to blood sampling (n = 50). We conducted a clinical trial (ClinicalTrials.gov identifier: NCT02383797) of live VZV vaccine on five subjects with CHH who lacked varicella history, had no clinical symptoms of immunodeficiency, and were seronegative for VZV; humoral and cellular immunologic responses were assessed post-immunization.

Results

A large proportion of patients have been immunized with live viral vaccines, including measles-mumps-rubella (MMR) (n = 40, 38%) and VZV (n = 10, 10%) vaccines, with no serious adverse events. Of the 50 patients tested for antibodies, previous immunization has been documented with MMR (n = 22), rubella (n = 2) and measles (n = 1) vaccines. Patients with CHH demonstrated seropositivity rates of 96%/75%/91% to measles, mumps and rubella, respectively, measured at a medium of 24 years post-immunization. Clinical trial participants developed humoral and cellular responses to VZV vaccine. One trial participant developed post-immunization rash and knee swelling, both resolved without treatment.

Conclusion

No serious adverse events have been recorded after immunization with live viral vaccines in Finnish patients with CHH. Patients generate humoral and cellular immune response to live viral vaccines. Immunization with live vaccines may be considered in selected CHH patients with no or clinically mild immunodeficiency.

Serum 25-hydroxyvitamin D concentration in childhood and risk of islet autoimmunity and type 1 diabetes: the TRIGR nested case-control ancillary study

AIMS/HYPOTHESIS

Our aim was to study the association between serum 25-hydroxyvitamin D (25OHD) concentration and islet autoimmunity and type 1 diabetes in children with an increased genetic risk of type 1 diabetes.

METHODS

Serum samples for 25OHD measurements were obtained in the Trial to Reduce IDDM in the Genetically at Risk (TRIGR) ancillary study (Divia) from children in 15 countries. Case children (n = 244) were defined as having positivity for at least two out of four diabetes-associated autoantibodies measured at any one sample. For each case child, two control children were selected matched for country and date of birth (±1 year) (n = 488). Of the case children, 144 developed type 1 diabetes. Serum 25OHD was measured repeatedly in infancy and childhood and was compared according to age at the first seroconversion (at 6, 12 and 18 months prior to and at seroconversion) and calendar age (0, 6, 12 and 18 months).

RESULTS

In children with islet autoimmunity, mean serum 25OHD concentration was lower 18 months prior to the age of first seroconversion of the case children compared with the control children (57.7 vs 64.8 nmol/l, p = 0.007). In children with type 1 diabetes (n = 144), mean serum 25OHD concentration was lower 18 months prior to the age of the first seroconversion (58.0 vs 65.0 nmol/l, p = 0.018) and at the calendar age of 12 months (70.1 vs 75.9 nmol/l, p = 0.031) than in their control counterparts. Analyses were adjusted for month of sample collection, human leucocyte antigen genotype, maternal type 1 diabetes and sex.

CONCLUSIONS/INTERPRETATION

The results suggest that early postnatal vitamin D may confer protection against the development of type 1 diabetes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00179777.

Fungal Dysbiosis and Intestinal Inflammation in Children With Beta-Cell Autoimmunity

Although gut bacterial dysbiosis is recognized as a regulator of beta-cell autoimmunity, no data is available on fungal dysbiosis in the children at the risk of type 1 diabetes (T1D). We hypothesized that the co-occurrence of fungal and bacterial dysbiosis contributes to the intestinal inflammation and autoimmune destruction of insulin-producing beta-cells in T1D. Fecal and blood samples were collected from 26 children tested positive for at least one diabetes-associated autoantibody (IAA, GADA, IA-2A or ICA) and matched autoantibody-negative children with HLA-conferred susceptibility to T1D (matched for HLA-DQB1 haplotype, age, gender and early childhood nutrition). Bacterial 16S and fungal ITS2 sequencing, and analyses of the markers of intestinal inflammation, namely fecal human beta-defensin-2 (HBD2), calprotectin and secretory total IgA, were performed. Anti-Saccharomyces cerevisiae antibodies (ASCA) and circulating cytokines, IFNG, IL-17 and IL-22, were studied. After these analyses, the children were followed for development of clinical T1D (median 8 years and 8 months). Nine autoantibody positive children were diagnosed with T1D, whereas none of the autoantibody negative children developed T1D during the follow-up. Fungal dysbiosis, characterized by high abundance of fecal Saccharomyces and Candida, was found in the progressors, i.e., children with beta-cell autoimmunity who during the follow-up progressed to clinical T1D. These children showed also bacterial dysbiosis, i.e., increased Bacteroidales and Clostridiales ratio, which was, however, found also in the non-progressors, and is thus a common nominator in the children with beta-cell autoimmunity. Furthermore, the progressors showed markers of intestinal inflammation detected as increased levels of fecal HBD2 and ASCA IgG to fungal antigens. We conclude that the fungal and bacterial dysbiosis, and intestinal inflammation are associated with the development of T1D in children with beta-cell autoimmunity.

Maturation of Gut Microbiota and Circulating Regulatory T Cells and Development of IgE Sensitization in Early Life

Recent studies suggest that the cross-talk between the gut microbiota and human immune system during the first year of life is an important regulator of the later development of atopic diseases. We explored the changes in the gut microbiota, blood regulatory T cells, and atopic sensitization in a birth-cohort of Estonian and Finnish children followed from 3 to 36 months of age. We describe here an infant Treg phenotype characterized by high Treg frequency, the maturation of Treg population characterized by a decrease in their frequency accompanied with an increase in the highly activated Treg cells. These changes in Treg population associated first with the relative abundance of Bifidobacterium longum followed by increasing colonization with butyrate producing bacteria. High bifidobacterial abundance in the neonatal microbiota appeared to be protective, while colonization with Bacteroides and E. coli was associated with later risk of allergy. Estonian children with lower risk of IgE mediated allergic diseases than Finnish children showed an earlier maturation of the gut microbiota, detected as earlier switch to an increasing abundance of butyrate-producing bacteria, combined with an earlier maturation of Treg cell phenotype and total IgE production. The children with established allergic diseases by age 3 showed a decreased abundance of butyrate producing Faecalibacterium. These results suggest that as well as the maintenance of a bifidobacterial dominated gut microbiota is important during the first weeks of life, the overtake by butyrate producing bacteria seems to be a beneficial shift, which should not be postponed.

Early Detection of Peripheral Blood Cell Signature in Children Developing β-Cell Autoimmunity at a Young Age

The appearance of type 1 diabetes (T1D)-associated autoantibodies is the first and only measurable parameter to predict progression toward T1D in genetically susceptible individuals. However, autoantibodies indicate an active autoimmune reaction, wherein the immune tolerance is already broken. Therefore, there is a clear and urgent need for new biomarkers that predict the onset of the autoimmune reaction preceding autoantibody positivity or reflect progressive β-cell destruction. Here we report the mRNA sequencing-based analysis of 306 samples including fractionated samples of CD4⁺ and CD8⁺ T cells as well as CD4^-CD8^- cell fractions and unfractionated peripheral blood mononuclear cell samples longitudinally collected from seven children who developed β-cell autoimmunity (case subjects) at a young age and matched control subjects. We identified transcripts, including interleukin 32 (IL32), that were upregulated before T1D-associated autoantibodies appeared. Single-cell RNA sequencing studies revealed that high IL32 in case samples was contributed mainly by activated T cells and NK cells. Further, we showed that IL32 expression can be induced by a virus and cytokines in pancreatic islets and β-cells, respectively. The results provide a basis for early detection of aberrations in the immune system function before T1D and suggest a potential role for IL32 in the pathogenesis of T1D.

Microbiome and type 1 diabetes

The steep increase in the incidence of type 1 diabetes (T1D), in the Western world after World War II, cannot be explained solely by genetic factors but implies that this rise must be due to crucial interactions between predisposing genes and environmental changes. Three parallel phenomena in early childhood – the dynamic development of the immune system, maturation of the gut microbiome, and the appearance of the first T1D-associated autoantibodies – raise the question whether these phenomena might reflect causative relationships. Plenty of novel data on the role of the microbiome in the development of T1D has been published over recent years and this review summarizes recent findings regarding the associations between islet autoimmunity, T1D, and the intestinal microbiota.

Molecular Pathways Mediating Immunosuppression in Response to Prolonged Intensive Physical Training, Low-Energy Availability, and Intensive Weight Loss

Exercise and exercise-induced weight loss have a beneficial effect on overall health, including positive effects on molecular pathways associated with immune function, especially in overweight individuals. The main aim of our study was to assess how energy deprivation (i.e., “semi-starvation”) leading to substantial fat mass loss affects the immune system and immunosuppression in previously normal weight individuals. Thus, to address this hypothesis, we applied a high-throughput systems biology approach to better characterize potential key pathways associated with immune system modulation during intensive weight loss and subsequent weight regain. We examined 42 healthy female physique athletes (age 27.5 ± 4.0 years, body mass index 23.4 ± 1.7 kg/m²) volunteered into either a diet group (n = 25) or a control group (n = 17). For the diet group, the energy intake was reduced and exercise levels were increased to induce loss of fat mass that was subsequently regained during a recovery period. The control group was instructed to maintain their typical lifestyle, exercise levels, and energy intake at a constant level. For quantification of systems biology markers, fasting blood samples were drawn at three time points: baseline (PRE), at the end of the weight loss period (MID 21.1 ± 3.1 weeks after PRE), and at the end of the weight regain period (POST 18.4 ± 2.9 weeks after MID). In contrast to the control group, the diet group showed significant (false discovery rate <0.05) alteration of all measured immune function parameters—white blood cells (WBCs), immunoglobulin G glycome, leukocyte transcriptome, and cytokine profile. Integrative omics suggested effects on multiple levels of immune system as dysregulated hematopoiesis, suppressed immune cell proliferation, attenuated systemic inflammation, and loss of immune cell function by reduced antibody and chemokine secretion was implied after intense weight loss. During the weight regain period, the majority of the measured immune system parameters returned back to the baseline. In summary, this study elucidated a number of molecular pathways presumably explaining immunosuppression in individuals going through prolonged periods of intense training with low-energy availability. Our findings also reinforce the perception that the way in which weight loss is achieved (i.e., dietary restriction, exercise, or both) has a distinct effect on how the immune system is modulated.

No evidence of the role of early chemical exposure in the development of β-cell autoimmunity

Exposure to environmental chemicals can modulate the developing immune system, but its role in the pathogenesis of type 1 diabetes is largely unexplored. Our objective was to study the levels of circulating concentrations of environmental pollutants during the first years of life and their associations with the later risk of diabetes-predictive autoantibodies. From two birth-cohort studies including newborn infants with HLA-conferred susceptibility to type 1 diabetes (FINDIA and DIABIMMUNE), we identified case children with at least one biochemical diabetes-associated autoantibody (n = 30-40) and from one to four autoantibody-negative controls per each case child matched for age, gender, diabetes-related HLA-risk, delivery hospital, and, in FINDIA, also dietary intervention group. Plasma levels of 13 persistent organic pollutants and 14 per- and polyfluorinated substances were analyzed in cord blood and plasma samples taken at the age of 12 and 48 months. Both breastfeeding and the geographical living environment showed association with circulating concentrations of some of the chemicals. Breastfeeding-adjusted conditional logistic regression model showed association between decreased plasma HBC concentration at 12-month-old children and the appearance of diabetes-associated autoantibodies (HR, 0.989; 95% Cl, 0.978-1.000; P = 0.048). No association was found between the plasma chemical levels and the development of clinical type 1 diabetes. Our results do not support the view that exposure to the studied environmental chemicals during fetal life or early childhood is a significant risk factor for later development of β-cell autoimmunity and type 1 diabetes.

Modulation of Type 1 Diabetes Risk by the Intestinal Microbiome

PURPOSE OF REVIEW

The purpose of this review is to summarize potential modulations of the intestinal microbiome aimed at preventing or delaying progression to overt type 1 diabetes in the light of recently identified perturbations of the gut microbiota associated with the development of type 1 diabetes.

RECENT FINDINGS

Accumulated data suggest that the gut microbiota is involved at two different steps in the evolution of type 1 diabetes. At the first step, the intestinal tract is colonized by a microbial community unable to provide an adequate education of the immune system. As a consequence, the infant acquires susceptibility to immune-mediated diseases, type 1 diabetes included. At the other step, the young child seroconverts to positivity for diabetes-associated autoantibodies. This is preceded or accompanied by a decrease in the diversity of the intestinal microbiota and an increased abundance of Bacteroides species. These changes will affect the disease process promoting progression toward overt type 1 diabetes. By providing specific probiotics, one can affect the colonization of the intestinal tract in the newborn infant or strengthen the immune education in early life. Human milk oligosaccharides function as nutrients for "healthy" bacteria. Dietary interventions applying modified starches can influence the numbers and activities of both autoreactive and regulatory T cells and provide protection against autoimmune diabetes in non-obese diabetic mice. Modulation of the intestinal microbiome holds the promise of effective protection against human type 1 diabetes.

Altered Fecal Microbiota in Paediatric Inflammatory Bowel Disease

BACKGROUND AND AIMS

Several factors support the view of inflammatory bowel disease [IBD] origin in the host responsiveness to intestinal bacteria, although no single bacterial species has been shown as a causative agent in the pathogenesis. Our aim was to analyse the fecal microbiota of paediatric IBD patients at different stages of the disease. In addition, the characteristics of immune response to the bacterial isolates showing very low abundance in IBD were studied.

METHODS

Fecal samples [1-3 samples/child] were collected from 10 paediatric patients with crohn's disease [CD], and 12 with ulcerative colitis [UC] and from 8 healthy children, for polyphasic microbiological analysis (culture, real-time polymerase chain reaction [PCR], and denaturing gradient gel electrophoresis). In addition, in vitro cytokine responses of peripheral blood mononuclear cells to the bacterial isolates, which showed very low abundance in IBD, were studied.

RESULTS

Although predominant bacterial diversity was higher in IBD, the numbers of Lachnospiraceae and Coriobacteriaceae bacteria were lower in IBD patients as compared with control children [p < 0.05]. In addition, Ruminococcaceae population diversity was lower in IBD [p < 0.05] and correlated negatively with fecal calprotectin levels. Both abundance and diversity of bifidobacterial populations were lower in children with IBD [p < 0.05], and particularly low numbers of certain bifidobacterial isolates were detected. In CD, we found enhanced up-regulation of interleukin-6 transcripts and impaired RAR-related orphan receptor C response to bifidobacteria, whereas decreased interferon-gamma response was observed in both CD and UC.

CONCLUSION

We demonstrate altered fecal microbiota in paediatric IBD, particularly low numbers and diversity of bifidobacterial populations. Interestingly, immunological response to bifidobacteria differed between paediatric CD patients and control children.

Th1/Th17 plasticity is a marker of advanced β cell autoimmunity and impaired glucose tolerance in humans

Upregulation of IL-17 immunity and detrimental effects of IL-17 on human islets have been implicated in human type 1 diabetes. In animal models, the plasticity of Th1/Th17 cells contributes to the development of autoimmune diabetes. In this study, we demonstrate that the upregulation of the IL-17 pathway and Th1/Th17 plasticity in peripheral blood are markers of advanced β cell autoimmunity and impaired β cell function in human type 1 diabetes. Activated Th17 immunity was observed in the late stage of preclinical diabetes in children with β cell autoimmunity and impaired glucose tolerance, but not in children with early β cell autoimmunity. We found an increased ratio of IFN-γ/IL-17 expression in Th17 cells in children with advanced β cell autoimmunity, which correlated with HbA1c and plasma glucose concentrations in an oral glucose tolerance test, and thus impaired β cell function. Low expression of Helios was seen in Th17 cells, suggesting that Th1/Th17 cells are not converted thymus-derived regulatory T cells. Our results suggest that the development of Th1/Th17 plasticity may serve as a biomarker of disease progression from β cell autoantibody positivity to type 1 diabetes. These data in human type 1 diabetes emphasize the role of Th1/Th17 plasticity as a potential contributor to tissue destruction in autoimmune conditions.

No association between vitamin D and β-cell autoimmunity in Finnish and Estonian children

BACKGROUND

Vitamin D has immunomodulatory properties, such as regulation of FOXP3 expression and regulatory T-cell activity. Our aim was to investigate whether plasma 25-hydroxyvitamin D [25(OH)D] concentrations associate with the development of β-cell autoimmunity and the transcriptional activity of FOXP3 or vitamin D3 convertase gene (CYP27B1) in CD4+ memory T cells.

METHODS

We studied 83 Finnish and 32 Estonian children participating in the DIABIMMUNE and DIPP studies. Twenty-nine Finnish and six Estonian children tested positive for at least one diabetes-associated autoantibody. The plasma concentrations of 25(OH)D and 1,25(OH)₂D were analysed with an enzyme immunoassay. Gene expression of FOXP3 and CYP27B1 in the isolated CD4+ memory T cells was studied with reverse transcription quantitative polymerase chain reaction.

RESULTS

Vitamin D status did not differ between subjects positive and negative for β-cell autoantibodies. Finnish children had higher vitamin D status than Estonian children (p < 0.001). FOXP3 expression was higher in Estonian CD4+ memory T-cell samples than in Finnish samples (p < 0.01) even when including in both groups only children with serum 25(OH)D concentrations in the range of 50-80 nmol/L (p < 0.001).

CONCLUSIONS

These findings do not support a crucial role of circulating 25(OH)D as a regulator of β-cell autoimmunity or FOXP3 expression.

Expression analysis of immune response genes in fish epithelial cells following ranavirus infection

Ranaviruses (family Iridoviridae) are a growing threat to fish and amphibian populations worldwide. The immune response to ranavirus infection has been studied in amphibians, but little is known about the responses elicited in piscine hosts. In this study, the immune response and apoptosis induced by ranaviruses were investigated in fish epithelial cells. Epithelioma papulosum cyprini (EPC) cells were infected with four different viral isolates: epizootic haematopoietic necrosis virus (EHNV), frog virus 3 (FV3), European catfish virus (ECV) and doctor fish virus (DFV). Quantitative real-time PCR (qPCR) assays were developed to measure the mRNA expression of immune response genes during ranavirus infection. The target genes included tumour necrosis factor α (TNF-α), interleukin-1β (IL-1β), β2-microglobulin (β2M), interleukin-10 (IL-10) and transforming growth factor β (TGF-β). All ranaviruses elicited changes in immune gene expression. EHNV and FV3 caused a strong pro-inflammatory response with an increase in the expression of both IL-1β and TNF-α, whereas ECV and DFV evoked transient up-regulation of regulatory cytokine TGF-β. Additionally, all viral isolates induced increased β2M expression as well as apoptosis in the EPC cells. Our results indicate that epithelial cells can serve as an in vitro model for studying the mechanisms of immune response in the piscine host in the first stages of ranavirus infection.

IL-17 immunity in human type 1 diabetes

Th17 immunity has been shown to regulate autoimmune diabetes in mice. IL-17 neutralization prevented development of diabetes when given postinitiation of insulitis but not earlier, suggesting interference with the effector phase of the disease. Islet-cell Ag-specific Th17 cells converted into IFN-gamma-secreting Th1-like cells and caused diabetes in mice recipients. The role of IL-17 in human type 1 diabetes (T1D) is, however, not established. In this study, we show upregulation of Th17 immunity in peripheral blood T cells from children with T1D. This was characterized by increased IL-17 secretion and expression of IL-17, IL-22, and retinoic acid-related orphan receptor C isoform 2, but also FOXP3 transcripts upon T cell activation in vitro. Also, circulating memory CD4 cells from children with T1D showed the same pattern of IL-17, IL-22 and FOXP3 mRNA upregulation, indicating IL-17 pathway activation in vivo. IL-17-positive T cells appeared to be CD4(+) cells expressing TCR-alphabeta and CCR6, and a subpopulation showed coproduction of IFN-gamma. Given the Th17 immunity in T1D, we demonstrated that IL-17 had detrimental effects on human islet cells in vitro; it potentiated both inflammatory and proapoptotic responses. Our findings highlight the role of IL-17 immunity in the pathogenesis of human T1D and point to a potential therapeutic strategy.

Increased FOXP3 expression in small-bowel mucosa of children with coeliac disease and type I diabetes mellitus

OBJECTIVE

To determine whether the expression of FOXP3 is changed in small-bowel mucosa in coeliac disease (CD).

MATERIAL AND METHODS

The study comprised 52 patients (mean age 8.01+/-6.14 years) who had undergone small-bowel biopsies. CD only was diagnosed in 16 patients, and CD with type I diabetes mellitus (T1D) in 7. These 23 patients and 4 others without CD had partial or subtotal villous atrophy (PVA, SVA). Twenty-five persons without CD had normal mucosa. The transcription level of the FOXP3 gene (Hs00203958_m1) was evaluated in biopsy samples (small bowel) using TaqMan gene expression assays. FOXP3 protein in mucosal cells was evaluated with mouse anti-human FOXP3 antibodies and CD25(+), and CD4(+) T cells were evaluated by mouse monoclonal antibodies.

RESULTS

Expression of FOXP3 mRNA was higher in both PVA and SVA compared to normal mucosa (p=0.007). Patients with CD and T1D had higher expression of FOXP3 mRNA than patients with CD alone (p=0.02). The number of FOXP3(+) cells in intestinal mucosa was higher in patients with CD, especially those with coexisting T1D, than in those with normal mucosa (p=0.01). The results of double staining showed that, among all positive cells, FOXP3 expression alone was revealed in 25.6% of the cells, CD25 positivity in 18% and both markers simultaneously were found in 56.5% of lymphocytes (p=0.03). Double staining for CD4 and FOXP3 showed that 87.5% of cells were CD4(+), 2.8% were FOXP3(+) and 9.7% of cells simultaneously expressed the CD4 and FOXP3 markers.

CONCLUSIONS

A more pronounced expression of FOXP3 mRNA and also the number of FOXP3(+) cells (with simultaneous expression of CD25 and CD4 markers) were found in the small-bowel biopsy specimens obtained from children with CD, particularly those with coexisting T1D, compared with the FOXP3 expression in normal mucosa.

No evidence for activation of T(H)1 or T(H)17 pathways in unstimulated peripheral blood mononuclear cells from children with β-cell autoimmunity or T1D

Introduction

The balance between T_H1, T_H2, T_H17, and regulatory T cells has been suggested to be disturbed in type 1 diabetes (T1D). We investigated this balance in peripheral blood mononuclear cells (PBMC) from children at risk of developing T1D and children with T1D.

Methods

We studied PBMC expression levels of markers related to T_H1 (T-bet, IL-12Rβ₁, IL-12Rβ₂), T_H2 (GATA-3, IL-4Rα), T_H17 (IL-17A), and regulatory T cells (Foxp3, ICOS, and CTLA-4) with real-time polymerase chain reaction from 17 children with T1D, 13 children with β-cell autoimmunity, 15 children with T1D risk-associated human leukocyte antigen (HLA) haplotypes, and 24 healthy, control children.

Results

We observed decreased expression levels of GATA-3 by PBMC of healthy children with autoantibodies compared to healthy, control children (p = 0.014) or children with HLA risk alleles (p = 0.032). Children with T1D demonstrated lower expression levels of T-bet, IL-12Rβ₁, and IL-4Rα both at diagnosis and 12 months later.

Conclusion

We found no indication of aberrant activation of T_H1, T_H17, or Treg in peripheral blood from children with or without risk of T1D. The observed immunological differences between children at risk of and with T1D should be considered when immunopathogenesis of β-cell destruction is studied.

Increased activation of GATA-3, IL-2 and IL-5 of cord blood mononuclear cells in infants with IgE sensitization

Risk of allergic diseases has been linked to abnormal patterns of fetal immune development, suggesting that priming of the immune system may occur in utero. The aim of the study was to investigate whether the pattern of immune response in cord blood mononuclear cells (CBMC) shows association with allergic diseases and IgE sensitization at 2 yr of age, and to study the effect of maternal probiotic supplementation on CBMC immune responses. CBMC were isolated from 98 neonates in a randomized double-blinded intervention study. CBMC were stimulated with beta-lactoglobulin, and phytohemaglutinin (PHA). Secretion of interferon-gamma (IFN-gamma), interleukin-5 (IL-5), and IL-13 was measured by an ELISA; IL-2, IL-4, and IL-10 by a cytokine bead assay. T-cell polarization-associated IL-4 receptor and IL-12R expressions, and the respective transcription factors GATA-3 and T-bet were analyzed with RT-PCR. The above responses were compared with the development of allergic diseases and IgE sensitization at 2 yr of age, and with the maternal probiotic or placebo supplementation. PHA-stimulated GATA-3 expression and IL-2 secretion in CBMC were higher in IgE-sensitized children at an age of 2 yr than in the non-sensitized, non-allergic children (p = 0.03 and 0.026). PHA-induced expression of GATA-3 correlated with IL-5 (p = 0.003, r = 0.300) and IL-13 (p = 0.007, r = 0.278) secretion of CBMC, and IL-5 secretion of beta-lactoglobulin-stimulated CBMC was higher in IgE-sensitized children at 2 yr of age than in the non-sensitized, non-allergic children (p = 0.013). Probiotic bacteria had no effect on CBMC immune responses. In CBMC-enhanced induction of GATA-3, which activates several Th2 cytokines genes, was a risk factor for IgE sensitization. The immune deviation towards Th2-type immunity developed already in utero and seemed to modulate the pattern of immune response favoring an IgE response to environmental antigens.

Decreased in vitro type 1 immune response against coxsackie virus B4 in children with type 1 diabetes

Enteroviruses, particularly Coxsackie virus B4 (CVB4), are considered to be involved in the pathogenesis of type 1 diabetes. We wanted to compare the characteristics of T-cell immune response to CVB4 in children with type 1 diabetes and healthy children with and without HLA risk-associated haplotypes (HLA-DR3-DQ2 or HLA-DR4-DQ8) for type 1 diabetes. Peripheral blood mononuclear cells (PBMCs) were isolated and cultured with CVB4 and analyzed for cytokine and chemokine receptors by flow cytometry and for expression of transcription factors Tbet and GATA-3 by RT-PCR and Western blot. Culture supernatants were analyzed for secretion of gamma-interferon (IFN-gamma). In children with type 1 diabetes, a decreased percentage of T-cells expressed CCR2, CXCR6, interleukin (IL)-18R, and IL-12Rbeta2-chain after in vitro stimulation with CVB4 in comparison with healthy children with or without HLA risk genotype. Moreover, we found that children with type 1 diabetes had decreased IFN-gamma secretion and expression of Tbet, both on mRNA and protein level, in CVB4-stimulated PBMCs. Accordingly, children with type 1 diabetes show an impaired type 1 immune response against CVB4 compared with healthy children. This may lead to a delayed clearance of the virus and, at least partly, explain why children with type 1 diabetes may be more prone to CVB4 infections and related complications, such as beta-cell damage.

Indicative oligodendrocyte dysfunction in spinal cords of human fetuses suffering from a lethal motoneuron disease

Human spinal cord development is still poorly understood and detailed molecular analyses of human motoneuron diseases could improve our understanding of the normal developmental processes of the spinal cord. Lethal Congenital Contracture Syndrome (LCCS, MIM 253310) provides a human model to study the early motoneuronal development. A typical phenotype of LCCS fetuses consists of multiple joint contractures, distinct facial features, and hydrops. Tissue pathology is characterized by severe muscle atrophy, lung hypoplasia, and degeneration of the anterior horn of the spinal cord as the hallmark of the syndrome. In this study we performed a global transcript analysis of LCCS spinal cords. The RNA expression profiles of these spinal cords were compared to age-matched healthy control fetuses, aborted for nonrelated causes. In addition, we applied phylogenetic footprinting methods to decipher the mechanisms of transcriptional regulation in the affected transcripts. Changes in transcripts involved with the development of the CNS and oligodendrocytes were obvious and the transcription factor PAX6 was identified as a key regulator during spinal cord development. In addition, transcript pathway analysis clearly indicated genes belonging to groups with neuronal functions to be affected. Our findings support the hypothesis that human motoneurons and oligodendrocytes are dependent on each other during their development and are influenced by distinct transcription factors previously known to act during murine and chick motoneuron development. These data provide valuable information about the molecular pathways putatively active in motoneuron diseases.

Cow milk is not responsible for most gastrointestinal immune-like syndromes--evidence from a population-based study

BACKGROUND

Gastrointestinal hypersensitivity to cow milk (CM) may be more common among school-aged children and young adults than previously thought.

OBJECTIVE

The objective was to study various gastrointestinal complaints and the immunologic mechanisms associated with food-related, especially CM-related, gastrointestinal disorders in young adults.

DESIGN

Of 827 subjects aged 16-21 y who completed a questionnaire on food-related gastrointestinal symptoms, 49 symptomatic subjects agreed to a clinical examination, including an interview, blood tests, a lactose-maldigestion test, a blinded CM challenge and, in severely symptomatic subjects (n = 12), an endoscopic examination. Twenty-nine subjects served as controls.

RESULTS

Approximately 10% of the subjects reported having major gastrointestinal symptoms, mainly food-related (n = 70 of 86), during the preceding year. Specific organic disease was found in 2 symptomatic subjects: 1 case of celiac disease and 1 of colitis. The result of the lactose-maldigestion test was positive in 16 of the remaining 47 symptomatic subjects, but only 4 carried the C/C(-13910) genotype for adult-type hypolactasia. The symptomatic subjects had restricted their consumption of certain foods, particularly CM. However, in a blinded challenge, CM-induced symptoms were rare. The symptomatic subjects had higher plasma soluble intercellular adhesion molecule 1 (P = 0.007) and lower granzyme A (P = 0.001) concentrations than did the control subjects. Duodenal biopsy samples tended to have higher intraepithelial CD3(+) cell counts (P = 0.065) and a higher expression of transforming growth factor beta (P = 0.073) and interleukin 12p35 messenger RNA (P = 0.075) than did the control subjects.

CONCLUSIONS

In an unselected cohort of young adults, 8% reported food-related gastrointestinal symptoms. The finding of immunologic activity implied the existence of a food-related gastrointestinal syndrome but not one induced by CM.

Frequency of allergic rhinitis to laboratory animals in university employees as confirmed by chamber challenges

BACKGROUND

Occupational risk for laboratory animal allergy (LAA) is well known, but prevention is often insufficient and new cases keep appearing.

METHODS

A questionnaire on work-related symptoms was sent to all laboratory animal workers in Kuopio University. Subjects with rhinitis were invited to an examination for LAA, which consisted of an otorhinolaryngological examination and skin prick testing (SPT) with 16 common environmental allergens and two to five relevant laboratory animals. In cases of occupational sensitization, a challenge test was performed.

RESULTS

The questionnaire was completed by 156 of 245 (64%) subjects. Rhinitis was reported by 65 of the respondents (42%) of whom 47 were examined for LAA. The duration of exposure before the onset of rhinitis varied from 1 month to 18 years. Twenty-seven persons (57%) had a history of some previous atopic symptoms. Forty subjects (85%) showed positive reactions in SPT, 24 (51%) for laboratory animals. Fifteen of the 26 animal challenge tests performed were positive, confirming the diagnosis of occupational allergic rhinitis in three subjects, occupational dermatitis in five and both diseases in seven subjects. The frequency of occupational allergic rhinitis among all participants was 10 of 156 (6%).

CONCLUSIONS

Atopic constitution and work-related sensitization were common in rhinitic laboratory animal workers. Occupational allergic disease was diagnosed in nearly every third case.

Bisphenol A accumulation in the freshwater clam Pisidium amnicum at low temperatures

Toxicokinetics of (14)C-labeled bisphenol A (BPA) was studied in the small freshwater clam Pisidium amnicum at four ecologically relevant low temperatures (2, 6, 8, and 12 degrees C). The uptake clearance (k(u)) of BPA increased from 1.49 to 6.55 ml x g(-1) x h(-1) as temperature increased from 2 to 8 degrees C but decreased slightly again at the highest temperature. The depuration of BPA was very slow and statistically insignificant at 2 degrees C, but the depuration rate ( k(d)) increased linearly as temperature increased from 2 to 12 degrees C. The longest half-life of BPA in clam tissues, 221 h, was found at the lowest temperature, and the highest bioconcentration factor of 144 was measured at 8 degrees C. Data show that P. amnicum accumulates BPA so that the bioconcentration factor rises over 100 at each temperature tested. Further, the data demonstrate the importance of temperature on the processes that control both the uptake and elimination of this compound.

Radiosensitivity of dermal and tumor fibroblasts derived from the same patient

The in vitro radiosensitivity of dermal fibroblasts has been found to vary between individuals, and a number of studies have also shown that this parameter correlates with radiation-induced late injuries in clinical radiotherapy. In addition, certain genetic disorders are known to effect radiosensitivity, e.g. normal tissues of patients homozygous or heterozygous for the ataxia teleangiectasia gene show unusual sensitivity to radiation both in vivo and in vitro. Thus, it has been assumed that there is a genetically determined component resulting in a certain intrinsic cellular radiation response in an individual. To study this possible relationship between different cells of a specific patient, we established eight pairs of dermal and tumor fibroblast cultures. The donor patients had either adenocarcinoma of the uterus or squamous cell carcinoma (SCC) of the head and neck. The radiosensitivity of these strains was determined by a 96-well plate clonogenic assay, previously used by us for radiosensitivity testing of cancer cells. From a paired comparison, the values for the cell fraction surviving 2.0 Gy (SF2), of both fibroblast strains, were found to be on the same level in five out of eight cases. In patient 6, the SF2 of tumor fibroblasts was significantly higher than that of dermal fibroblasts (P=0.0014). In two additional cases the tendency was the same, but not statistically significant. As groups, the two types of fibroblasts did not differ from each other, mean SF2 values of 0.24+/-0.07 and 0.21+/-0.05, respectively. The SF2 of tumor fibroblasts from SCC patients proved to be significantly higher than that of the adenocarcinoma patients (P=0.030). These preliminary results indicate that the in vitro radiosensitivity of tumor fibroblasts correlates with normal cell sensitivity in many cases, but not in all. The radiosensitivity of tumor fibroblasts also seems to follow the level of in vitro radiosensitivity determined for the corresponding histological type of tumor cells. Further studies are needed to determine more closely the relationship between the radiosensitivities of tumor cells and tumor fibroblasts, thus evaluating the possibility of testing radiosensitivity from tumor fibroblasts in order to estimate tumor response.

Movement protein-derived resistance to triple gene block-containing plant viruses

Two mutant potato virus X (PVX) movement protein (MP) genes (m 12K-Sal and m 12K-Kpn) were obtained by inserting specific linkers at the boundary between the N-terminal hydrophobic and putative transmembrane segment, and the central invariant hydrophilic region of the respective 12 kDa, 12K, triple gene block (TGB) protein. Several transgenic potato lines which expressed m 12K-Sal or m 12K-Kpn to different degrees were resistant to infection by PVX, potato aucuba mosaic potexvirus and the carlaviruses potato virus M and S over a wide range of inoculum concentrations (3-300 micrograms/ml). However, they were not resistant to potato virus Y, which lacks a TGB protein. We suggest that the resistance of m 12K-Sal and m 12K-Kpn transgenic potato lines is MP-derived and not RNA-mediated.

Transgenic potato plants expressing mammalian 2'-5' oligoadenylate synthetase are protected from potato virus X infection under field conditions

We cloned and sequenced a rat cDNA encoding the 2'-5' oligoadenylate synthetase, a component of the mammalian interferon-induced antiviral response, and used Agrobacterium-mediated transformation to generate transgenic potato clones expressing this mammalian enzyme. In transgenic plants infected with potato virus X and followed under field conditions, virus concentrations in leaves and in tubers were significantly lower than in nontransgenic controls. Additionally, virus concentration in the leaves of five transgenic clones and in tubers of one clone was also lower than in transgenic potatoes expressing potato virus X coat protein.