General Immune Function Research Articles

Abstract CT242: Phase 2b study of alloHSCT patients receiving RGI-2001, an NKT cell activator, demonstrates safety and protection from acute GVHD, correlating with increased NKT cell number in patient blood

Abstract Background: Allogeneic hematopoietic stem cell transplant (alloHSCT) has potentially curative outcomes for patients with certain hematologic malignancies but also has toxicity due to graft-versus-host-disease (GVHD), where donor-derived T cells attack the immune suppressed recipient, leading to significant mortality and morbidity. Natural killer T (NKT) and T-regulatory (Treg) cell levels in the donor product or in the recipient associate with protection from acute GVHD (aGVHD) and thus may represent therapeutic targets. RGI-2001 is a liposomal formulation of an NKT cell agonist, expanding both NKT and Tregs in animal models, resulting in prevention of aGVHD without compromising general immune function. Phase 1/2a studies of RGI-2001 demonstrated safety and potential efficacy in reducing aGVHD in alloHSCT using single doses. In this Phase 2b study, RGI-2001 was given weekly x 6 doses (100 ug/kg) in combination with standard GVHD prophylaxis. Results: RGI-2001 was given to 48 subjects undergoing matched (8/8) alloHSCT. Control data from the CIBMTR (n=207) was obtained and used as comparison. Patients receiving RGI-2001 did not have any serious infusion reactions, related serious adverse events, cases of cytomegalovirus disease, post-transplant lymphoproliferative disease, or graft failure. Compared to the CIBMTR group, the RGI-2001 group demonstrated lower grade II-IV aGVHD (day 180) and higher aGHVD-free survival (GFS) and overall survival. Relapse and cGVHD rates were similar between the groups. In addition, the number of NKT cells in the blood of the RGI-2001 group correlated with specific outcomes within this group. Grade II-IV at day 100 or d180 or GFS d180 occurred in >8 patients, and the mean NKT numbers at day 28 for these patients is lower than patients without occurrence. The number and percentages of Tregs, CD4+ T cells, CD8+ T cells, and NK cells did not correlate with any clinical endpoints. Conclusions: RGI-2001 given weekly x 6 doses is safe and well tolerated. Compared to matched cohort, the RGI-2001 cohort had decreased aGVHD and increased overall survival, suggesting that RGI-2001 could be added to alloHSCT regimens to reduce aGVHD while not affecting overall immune responses against infection and tumor relapse. Future studies will focus on optimizing dosage based on blood levels of NKT cells, elucidating the mechanisms of actions of RGI-2001, and identifying potential biomarkers of response. Citation Format: Jack D. Bui, Calvin Lee, Christine Caron, Dana Lee, Zachariah DeFilipp, Yi-Bin Chen. Phase 2b study of alloHSCT patients receiving RGI-2001, an NKT cell activator, demonstrates safety and protection from acute GVHD, correlating with increased NKT cell number in patient blood [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT242.

The Gut Microbiome and Mental Health.

The gut microbiome has been well researched in the past few years and may be a target for treating mental illness. Trillions of bacteria in the digestive system work with the brain, immune function, and endocrine pathways. This gut microbiome ecosystem mediates the interaction between the human being and the environment making its inclusion in holistic nursing essential. Changes in normal balance of the gut microbiome occur with diet, antibiotics and other medications, stress, cancer treatment, geography and environment, and current illnesses. When the microbiome is challenged a "dysbiotic" state leads to inadequate production of needed neurotransmitters such as serotonin and dopamine. Research has shown links between the dysbiosis, and the inflammatory response system that are known to contribute to depression, anxiety, and schizophrenia. Understanding the role of the gut microbiome can be beneficial to holistic nurses, providing a new tool to prevent, treat, or reduce symptoms of mental illness and improve general immune function. This innocuous holistic approach to mental wellness is becoming an important evidenced-based approach.

Reduction in Social Media Usage Produces Improvements in Physical Health and Wellbeing: An RCT

Social media usage has increased over recent years and has been associated with negative effects on health and wellbeing. This study explored whether reducing smartphone screentime would improve health and wellbeing. Fifty students completed a battery of questionnaires regarding their health, immune function, loneliness, sleep, anxiety, and depression. They were allocated randomly to groups either using smartphones as normal (No Change), reducing usage by 15 min per day (Reduce), or reducing use by 15 min and substituting another activity during this time (Reduce + Activity). After 3 months, they completed the same questionnaires again. There was unexpectedly low compliance with the Reduce + Activity (leisure substitution) intervention. In contrast, there was a significant reduction in screentime for the Reduce group compared to the other two groups. There was a significant improvement in the Reduce group in general health, immune function, loneliness, and depression compared to the other groups. These findings extend previous results from similar studies and suggest limiting screentime may be beneficial to health and wellbeing.

Virally Suppressed People Living with HIV Who Use Opioids Have Diminished Latency Reversal.

Of the 12 million people who inject drugs worldwide, 13% live with HIV. Whether opioid use impacts HIV pathogenesis and latency is an outstanding question. To gain insight into whether opioid use influences the proviral landscape and latent HIV reservoir, we performed intact proviral DNA assays (IPDA) on peripheral blood mononuclear cells (PBMCs) from antiretroviral therapy (ART)-suppressed people living with HIV (PWH) with or without current opioid use. No differences were observed between PWH with and without opioid use in the frequency of HIV intact and defective proviral genomes. To evaluate the latent reservoir, we activated PBMCs from ART-suppressed PWH with or without opioid use and assessed the induction of HIV RNA. PWH using opioids had diminished responses to ex vivo HIV reactivation, suggesting a smaller reversible reservoir of HIV-1 latently infected cells. However, in vitro studies using primary CD4+ T cells treated with morphine showed no effect of opioids on HIV-1 infection, replication or latency establishment. The discrepancy in our results from in vitro and clinical samples suggests that while opioids may not directly impact HIV replication, latency and reactivation in CD4+ T cells, opioid use may indirectly shape the HIV reservoir in vivo by modulating general immune functions.

Self-perceived Mate Value is Predicted by Biological and self-reported Indices of Health in Young Adults.

Immunocompetence can influence an organism's reproductive fitness, and thus presumably their desirability as a mate (i.e., mate value). In humans, the link between immunocompetence and mate value has found circumstantial support by way of both expressed mate preferences for healthy partners, and via preferences for attractive phenotypes that are ostensibly linked to immune functioning. We examined whether a biological marker of immunocompetence, salivary immunoglobulin A (sIgA), along with self-reported frequency and severity of symptoms of poor health predicted individuals' reported mate value and mating behavior in a sample of 691 young adults. Our measures of immunocompetence (sIgA and symptoms of poor health) correlated significantly with one another, suggesting sIgA is a viable marker of general immune function in young adults. We then examined the independent contributions of these variables to mate value, controlling for age, sex, and body mass index (BMI). Results showed that sIgA (positively)and poor health (negatively) predicted mate value, but not lifetime number of sex partners or current romantic relationship status. These findings suggest that those with better health and immune function report being more desirable as mating partners but support past research showing null links to reported mating behavior. Together, these findings suggest that more comprehensive work on links between immunocompetence and mating is required.

Comparing the associations between host and tumor factors with survival outcomes with anti-PD-1 immunotherapy in metastatic melanoma.

Anti-programmed death-1 (PD-1) immunotherapy has drastically improved survival for metastatic melanoma; however, 50% of patients have progression within 6months despite treatment. In this study, we investigated host, and tumor factors for metastatic melanoma patients treated with anti-PD-1 immunotherapy. Patients treated with the anti-PD-1 immunotherapy between 2014 and 2017 were identified in Alberta, Canada. All patients had Stage IV melanoma. Patient characteristics, investigations, treatment, and clinical outcomes were obtained from electronic medical records. We identified 174 patients treated with anti-PD-1 immunotherapy. At 37.1months median follow-up time 135 (77.6%) individuals had died and 150 (86.2%) had progressed. An elevated lactate dehydrogenase (LDH) had a response rate of 21.0% versus 41.0% for those with a normal LDH (p=0.017). Host factors associated with worse median progression-free survival (mPFS) and median overall survival (mOS) included liver metastases, >3 sites of disease, elevated LDH, thrombocytosis, neutrophilia, anemia, lymphocytopenia, and an elevated neutrophil/lymphocyte ratio. Primary ulcerated tumors had a worse mOS of 11.8 versus 19.3 months (p=0.042). We identified four prognostic subgroups in advanced melanoma patients treated with anti-PD-1 therapy. (1) Normal LDH with <3 visceral sites, (2) normal LDH with ≥3 visceral sites, (3) LDH 1-2x upper limit of normal (ULN), (4) LDH ≥2x ULN. The mPFS each group was 14.0, 6.5, 3.3, and 1.9months, while the mOS for each group was 33.3, 15.7, 7.9, and 3.4months. Our study reports that host factors measuring the general immune function, markers of systemic inflammation, and tumor burden and location are the most prognostic for survival.

Risk of serious infections in multiple sclerosis patients by disease course and disability status: Results from a Swedish register-based study

Background and objectivesSerious infections are an emerging concern with increasing use of potent immunomodulation in multiple sclerosis (MS), but the extent to which MS disease features influence infectious susceptibility is poorly characterized. The objective of this study was to assess the associations of MS disease course and disability status with risk of serious infections. MethodsA cohort of 8660 MS patients was individually matched on age, sex and region of residence with 86,600 people without MS from the general population using national registers in Sweden. The study period was from 1996 to 2012, with follow-up until December 31, 2014. The main outcomes were infection as the underlying or contributory cause of death or infection-related hospital admission identified in the Cause of Death and Patient registers. MS disease course (relapsing-remitting or progressive disease) and Expanded Disability Status Scale (EDSS) score (six and over or below six) were extracted from the MS Register Hazard ratios (HRs) for any serious infection were estimated using flexible parametric models. ResultsDuring a median follow-up of 9.6 years (interquartile range = 5.5–13.5 years), 1337 MS patients experienced a serious infection. Compared with individually matched people without MS, risk of serious infection was greater for progressive disease (HR = 3.80; 95% CI 3.52: 4.09) than relapsing-remitting disease (HR = 1.77; 95% CI: 1.62:1.93). A similar pattern of risk was seen for dichotomised EDSS score (HR = 4.26; 95% CI 3.87: 4.70 for EDSS 6.0–9.5 and HR = 1.30; 95% CI 1.1853: 1.43 for EDSS 0.0–5.5). Overall, associations with greater disability did not notably differ by immunomodulatory therapy use, but associations with lower disability were more pronounced in patients receiving these therapies. ConclusionsDisease course or EDSS score (which may be more readily available than MS course in some patients) should be considered in individual management and monitoring of MS patients, including assessing benefit-risk of therapies that influence general immune function.

Rapid, efficient and activation-neutral gene editing of polyclonal primary human resting CD4+ T cells allows complex functional analyses

CD4+ T cells are central mediators of adaptive and innate immune responses and constitute a major reservoir for human immunodeficiency virus (HIV) in vivo. Detailed investigations of resting human CD4+ T cells have been precluded by the absence of efficient approaches for genetic manipulation limiting our understanding of HIV replication and restricting efforts to find a cure. Here we report a method for rapid, efficient, activation-neutral gene editing of resting, polyclonal human CD4+ T cells using optimized cell cultivation and nucleofection conditions of Cas9–guide RNA ribonucleoprotein complexes. Up to six genes, including HIV dependency and restriction factors, were knocked out individually or simultaneously and functionally characterized. Moreover, we demonstrate the knock in of double-stranded DNA donor templates into different endogenous loci, enabling the study of the physiological interplay of cellular and viral components at single-cell resolution. Together, this technique allows improved molecular and functional characterizations of HIV biology and general immune functions in resting CD4+ T cells.

Preexisting Mental Disorders Increase the Risk of COVID-19 Infection and Associated Mortality.

Coronavirus disease 2019 (COVID-19), a respiratory disease of unknown origin, has a high rate of morbidity and mortality. Individuals with mental disorders may have a higher risk of infection and worse clinical outcomes because of a variety of factors such as poorer general resilience and lower immune function. However, there have been no studies to date specifically investigating the risk of COVID-19 and associated mortality in these patients. This was addressed in the present study by analyzing the data of 473,958 subjects included in the UK Biobank, 14,877 of whom tested positive for COVID-19 infection. Logistic regression analysis was performed to evaluate the associations between mental disorders and risks of COVID-19 infection and associated mortality. The results showed that subjects who were diagnosed with a mental disorder had a significantly higher risk of developing COVID-19 and a worse outcome as evidenced by higher rates of COVID-19-related mortality, with the strongest effects observed for dementia. Among dementia subtypes, Alzheimer disease patients had the highest risks of COVID-19 infection (7.39-fold increase) and associated mortality (2.13-fold increase). Late-life anxiety only increased the risk of developing COVID-19 while late-life depression not only was associated with a higher risk of infection but also a worse outcome. These findings highlight the need to prioritize patients with mental disorders-especially those who experience these disorders later in life—when implementing preventive strategies such as vaccinations.

Role of vitamin D in COVID‐19 infections and deaths

Role of vitamin D in COVID‐19 infections and deaths

Prospective of low dose naltrexone use in treatment of autoimmune pathology and endometriosis

There are still many complex issues in the management of autoimmune pathologies in gynecology and reproductology, endometriosis in particular. Naltrexone, a competitive antagonist of opiate receptors in the central and peripheral nervous systems, reveals new qualities such as effects on autoimmune processes. Naltrexone in low doses of 1.7–5 mg (Low Dose Naltrexone, LDN) revealed the opposite effect on opiate receptors in the form of a rebound effect and, as a consequence, a strong increase in endogenous endorphins and enkephalins. Studies of elevated levels of these neurotransmitters have provided evidence of a multidisciplinary beneficial effect on the immune system of people with endorphin and enkephalin deficiency, an association between the endogenous opiate system and cells and tissue growth in general and healthy immune function was confirmed. The most explored effects of them are such as blocking the synthesis ofpro inflammatory cytokines IL-6, IL-12, tumor necrosis factor, the effect on neuroglia through toll-like receptors, the effect on the cycle cells growth, especially malignant tumor cells, through interaction with opiate growth factor, modulation synthesis of T- and B-lymphocytes. Growing evidence of LDN efficacy is becoming a potentially effective clinical practice in autoimmune pathologies, but still off-label used.Some data of clinical trials is presented. Four studies with Crohn's disease with results of relief of symptoms and remission, including experience in pediatrics. Three clinical trials with LDN results in multiple sclerosis with improved quality of life and improved symptoms. The scientific hypothesis suggests the success of LDN due to the reduction of induced nitric oxide synthase activity. The success of management of patients with malignant tumors is also presented. The article contains the latest data from clinical trials on reported serious and non-serious side effects of naltrexone at various doses, including data confirming the safety of taking mid-therapeutic naltrexone doses throughout pregnancy. These effects of LDN may prove to be effective in management patients with endometriosis.

Immune differences in captive and free-ranging zebras (Equus zebra and E. quagga)

Wild mammals in ex situ captivity experience substantially different environmental conditions compared to free-ranging conspecifics, e.g., in terms of diet, climatic conditions, social factors, movement space, and direct anthropogenic disturbance. Moreover, animals in captivity frequently undergo management interventions such as medical treatments which may influence pathogen pressure. Captivity is known to affect immunological responses in some terrestrial and marine mammals; however, it is unclear whether this can be generalized to other taxa. Furthermore, little is known about how energetically costly life history stages such as lactation influence the immune system in wildlife. We measured expression of components of the constitutive and induced innate immunity and of the adaptive immune system in plains and mountain zebras (Equus quagga and E. zebra), including lactating and non-lactating individuals. As a proxy for general immune function, we screened for lytic equine herpesvirus (EHV) infection, a common and often latent pathogen which is reactivated in response to stress and immune challenge. Both energetically cheap markers of the constitutive innate immunity were lower in captive than in wild zebras, whereas energetically costly markers of the induced innate immunity were more highly expressed in captive zebras. Lactation was associated with higher titers of natural antibodies and lysozyme. Lytic EHV infection was not significantly correlated with any of the measured immune markers. Our results suggest that captivity and lactation may influence immune functions in zebra mares.

Gender differences in the use of anti-infective medications before and after widowhood: a register-based study

BackgroundRecent findings suggest that bereavement due to spousal loss is associated with a decline in general immune functions, and thus to increased susceptibility to infections among widowed individuals. The present...

Liver-derived human mesenchymal stem cells: a novel therapeutic source for liver diseases.

Mesenchymal stem cells (MSCs) represent an attractive cell type for research and therapy due to their ability to proliferate, differentiate, modulate immune reactions, and secrete trophic factors. MSCs exist in a multitude of tissues, including bone marrow, umbilical cord, and adipose tissues. Moreover, MSCs have recently been isolated from the liver. Compared with other MSC types, liver-derived human MSCs (LHMSCs) possess general morphologies, immune functions, and differentiation capacities. Interestingly, LHMCSs produce higher levels of pro-angiogenic, anti-inflammatory, and anti-apoptotic cytokines than those of bone marrow-derived MSCs. Thus, these cells may be a promising therapeutic source for liver diseases. This paper summarizes the biological characteristics of LHMSCs and their potential benefits and risks for the treatment of liver diseases.

Antigen-Specific Killer Polylactic-Co-Glycolic Acid (PLGA) Microspheres Can Prolong Alloskin Graft Survival in a Murine Model

Background: The strategy of specifically depleting antigen-specific T cells can potentially be used for the treatment of allograft rejection and autoimmunity because it does not suppress the overall immune systems.Methods: In this study, we generated killer polylactic-co-glycolic acid (PLGA) microspheres by covalently coupling major histocompatibility complex (MHC) class I antigens and apoptosis-inducing anti-Fas monoclonal antibody (mAb) onto PLGA microspheres. A modified double-emulsion method was used for the preparation of cell-sized PLGA microspheres. H-2Kb/peptide monomers were generated in-house and analyzed through flow cytometry. The killer PLGA microspheres were administered intravenously into BALB/c mice (H-2Kd) that had previously been grafted with skin squares from C57BL/6 mice (H-2Kb). Tumor cell challenge and third-party mixed lymphocyte culture were used to assess the general immune functions of host.Results: The alloskin graft survival was prolonged by 4 days. The killer PLGA microspheres could specifically deplete the H-2Kb alloantigen-reactive CD8+ T cells that infiltrated into the alloskin graft but not CD4+ T cells, without impairment of host overall immune function.Conclusions: Here, we initially report that PLGA microspheres, which have been widely used as medicine-delivering carriers, were used to prepare antigen-specific killer complexes and treat allograft rejection. Our data highlight the therapeutic potential of this biocompatible and biodegradable antigen-specific killer effector for the treatment of allograft rejection and autoimmune disease.

Immunotherapy for malignant gliomas.

Cancer immunotherapy aims to harness the innate ability of the immune system to recognize and destroy malignant cells. Immunotherapy for malignant gliomas is an emerging field that promises the possibility of highly specific and less toxic treatment compared to conventional chemotherapy. In addition, immunotherapy has the added benefit of sustained efficacy once immunologic memory is induced. Although there are numerous therapeutic agents that boost general immune function and facilitate improved antitumor immunity, to date, immunotherapy for gliomas has focused primarily on active vaccination against tumor-specific antigens. The results of numerous early phase clinical trials demonstrate promising results for vaccine therapy, but no therapy has yet proven to improve survival in a randomized, controlled trial. The major barrier to immunotherapy in malignant gliomas is tumor-induced immunosuppression. The mechanisms of immunosuppression are only now being elucidated, but clearly involve a combination of factors including regulatory T cells, tumor-associated PD-L1 expression, and CTLA-4 signaling. Immunomodulatory agents have been developed to combat these immunosuppressive factors and have demonstrated efficacy in other cancers. The future of glioma immunotherapy likely lies in a combination of active vaccination and immune checkpoint inhibition.

An evidence-based update on the pharmacological activities and possible molecular targets of Lycium barbarum polysaccharides.

Lycium barbarum berries, also named wolfberry, Fructus lycii, and Goji berries, have been used in the People’s Republic of China and other Asian countries for more than 2,000 years as a traditional medicinal herb and food supplement. L. barbarum polysaccharides (LBPs) are the primary active components of L. barbarum berries and have been reported to possess a wide array of pharmacological activities. Herein, we update our knowledge on the main pharmacological activities and possible molecular targets of LBPs. Several clinical studies in healthy subjects show that consumption of wolfberry juice improves general wellbeing and immune functions. LBPs are reported to have antioxidative and antiaging properties in different models. LBPs show antitumor activities against various types of cancer cells and inhibit tumor growth in nude mice through induction of apoptosis and cell cycle arrest. LBPs may potentiate the efficacy of lymphokine activated killer/interleukin-2 combination therapy in cancer patients. LBPs exhibit significant hypoglycemic effects and insulin-sensitizing activity by increasing glucose metabolism and insulin secretion and promoting pancreatic β-cell proliferation. They protect retinal ganglion cells in experimental models of glaucoma. LBPs protect the liver from injuries due to exposure to toxic chemicals or other insults. They also show potent immunoenhancing activities in vitro and in vivo. Furthermore, LBPs protect against neuronal injury and loss induced by β-amyloid peptide, glutamate excitotoxicity, ischemic/reperfusion, and other neurotoxic insults. LBPs ameliorate the symptoms of mice with Alzheimer’s disease and enhance neurogenesis in the hippocampus and subventricular zone, improving learning and memory abilities. They reduce irradiation- or chemotherapy-induced organ toxicities. LBPs are beneficial to male reproduction by increasing the quality, quantity, and motility of sperm, improving sexual performance, and protecting the testis against toxic insults. Moreover, LBPs exhibit hypolipidemic, cardioprotective, antiviral, and antiinflammatory activities. There is increasing evidence from preclinical and clinical studies supporting the therapeutic and health-promoting effects of LBPs, but further mechanistic and clinical studies are warranted to establish the dose–response relationships and safety profiles of LBPs.

Immunosenescence and resistance to parasite infection in the honey bee, Apis mellifera

Immunosenescence, the systemic reduction of immune efficiency with age, is increasingly recognised as having important implications for host-parasite dynamics. Changes in the immune response can impact on the ability of an individual to resist or moderate parasite infection, depending on how and when it encounters a parasite challenge. Using the European honey bee Apis mellifera and its microsporidian parasite Nosema ceranae, we investigated the effects of host age on the ability to resist parasite infection and on baseline immunocompetence, assessed by quantifying constitutive (PO) and potential levels (PPO) of the phenoloxidase immune enzyme as general measures of immune function. There was a significant correlation between the level of general immune function and infection intensity, but not with survival, and changes in immune function with age correlated with the ability of individuals to resist parasite infection. Older individuals had better survival when challenged with a parasite than younger individuals, however they also had more intense infections and lower baseline immunocomptence. The ability of older individuals to have high infection intensities yet live longer, has potential consequences for parasite transmission. The results highlight the need to consider age in host-parasite studies and show the importance of choosing the correct measure when assaying invertebrate immunity.

Influence of feeding a low-phosphorus diet on leucocyte function in dairy cows

Phosphorus depletion and hypophosphatemia have been described to interfere with immune function in rats and humans. In dairy cows, hypophosphatemia has been associated with muscle weakness and recumbency as well as with intravascular hemolysis resulting from increased osmotic fragility of erythrocytes, but so far, the influence of P depletion and hypophosphatemia on immune function has not been studied. Therefore, the aim of this study was to investigate whether P depletion and ensuing hypophosphatemia are associated with impaired granulocyte and lymphocyte function. Eight mid-lactation dairy cows were fed a P-deficient ration (0.2% P/kg of DM) for a period of 4wk. The depletion phase was preceded by a 2-wk acclimatization period and followed by a 2-wk repletion phase, during which the same ration was supplemented with P to meet or exceed daily requirements. Blood samples were collected at the end of the acclimatization period, after 2 and 4wk of P depletion, and at the end of the repletion phase. Plasma phosphate concentrations ([Pi]) were determined and white blood cells were counted and isolated. General immune function was investigated by performing a phagocytosis assay with Staphylococcus aureus and a lymphocyte stimulation test (LST) with concanavalin A and pokeweed mitogen. The plasma [Pi] decreased significantly, with the lowest values (mean 0.7±0.2mmol/L) occurring after 2wk of depletion, although depletion was continued for another 2wk. During repletion, plasma [Pi] increased above baseline concentrations. Granulocyte counts changed in parallel with plasma [Pi] over time, decreasing significantly at 2wk after P depletion and increasing again thereafter. Granulocyte survival after phagocytosis was lowest after 4wk of P depletion. Phagocytosis activity of surviving granulocytes determined by mean fluorescence intensity was higher, indicating that phagocytosis was not negatively influenced by P depletion. Lymphocyte stimulation showed a similar trend, with a decreasing stimulation index at the end of P depletion, but differences were not statistically significant. Data presented in this study indicate that hypophosphatemia leads to a decrease in granulocyte counts. Chronic P depletion impairs granulocyte survival during phagocytosis but not phagocytosis activity. Lymphocyte function is not influenced by P depletion.

Proteome Response of Tribolium castaneum Larvae to Bacillus thuringiensis Toxin Producing Strains

Susceptibility of Tribolium castaneum (Tc) larvae was determined against spore-crystal mixtures of five coleopteran specific and one lepidopteran specific Bacillus thuringiensis Cry toxin producing strains and those containing the structurally unrelated Cry3Ba and Cry23Aa/Cry37Aa proteins were found toxic (LC50 values 13.53 and 6.30 µg spore-crystal mixture/µL flour disc, respectively). Using iTRAQ combined with LC-MS/MS allowed the discovery of seven novel differentially expressed proteins in early response of Tc larvae to the two active spore-crystal mixtures. Proteins showing a statistically significant change in treated larvae compared to non-intoxicated larvae fell into two major categories; up-regulated proteins were involved in host defense (odorant binding protein C12, apolipophorin-III and chemosensory protein 18) and down-regulated proteins were linked to metabolic pathways affecting larval metabolism and development (pyruvate dehydrogenase Eα subunit, cuticular protein, ribosomal protein L13a and apolipoprotein LI-II). Among increased proteins, Odorant binding protein C12 showed the highest change, 4-fold increase in both toxin treatments. The protein displayed amino acid sequence and structural homology to Tenebrio molitor 12 kDa hemolymph protein b precursor, a non-olfactory odorant binding protein. Analysis of mRNA expression and mortality assays in Odorant binding protein C12 silenced larvae were consistent with a general immune defense function of non-olfactory odorant binding proteins. Regarding down-regulated proteins, at the transcriptional level, pyruvate dehydrogenase and cuticular genes were decreased in Tc larvae exposed to the Cry3Ba producing strain compared to the Cry23Aa/Cry37Aa producing strain, which may contribute to the developmental arrest that we observed with larvae fed the Cry3Ba producing strain. Results demonstrated a distinct host transcriptional regulation depending upon the Cry toxin treatment. Knowledge on how insects respond to Bt intoxication will allow designing more effective management strategies for pest control.