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| 2. |
- Mega, Alessandro, et al.
(author)
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A PDGFRB- and CD40-targeting bispecific AffiMab induces stroma-targeted immune cell activation
- 2023
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In: mAbs. - : Informa UK Limited. - 1942-0862 .- 1942-0870. ; 15:1
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Journal article (peer-reviewed)abstract
- CD40 agonism by systemic administration of CD40 monoclonal antibodies has been explored in clinical trials for immunotherapy of cancer, uncovering enormous potential, but also dosing challenges in terms of systemic toxicity. CD40-dependent activation of antigen presenting cells is dependent on crosslinking of the CD40 receptor. Here we exploited this requisite by coupling crosslinking to cancer-receptor density by dual-targeting of CD40 and platelet-derived growth factor receptor beta (PDGFRB), which is highly expressed in the stroma of various types of tumors. A novel PDGFRBxCD40 Fc-silenced bispecific AffiMab was developed to this end to test whether it is possible to activate CD40 in a PDGFRB-targeted manner. A PDGFRB-binding Affibody molecule was fused to each heavy chain of an Fc-silenced CD40 agonistic monoclonal antibody to obtain a bispecific "AffiMab". Binding of the AffiMab to both PDGFRB and CD40 was confirmed by surface plasmon resonance, bio-layer interferometry and flow cytometry, through analysis of cells expressing respective target. In a reporter assay, the AffiMab displayed increased CD40 potency in the presence of PDGFRB-conjugated beads, in a manner dependent on PDGFRB amount/bead. To test the concept in immunologically relevant systems with physiological levels of CD40 expression, the AffiMab was tested in human monocyte-derived dendritic cells (moDCs) and B cells. Expression of activation markers was increased in moDCs specifically in the presence of PDGFRB-conjugated beads upon AffiMab treatment, while the Fc-silenced CD40 mAb did not stimulate CD40 activation. As expected, the AffiMab did not activate moDCs in the presence of unconjugated beads. Finally, in a co-culture experiment, the AffiMab activated moDCs and B cells in the presence of PDGFRB-expressing cells, but not in co-cultures with PDGFRB-negative cells. Collectively, these results suggest the possibility to activate CD40 in a PDGFRB-targeted manner in vitro. This encourages further investigation and the development of such an approach for the treatment of solid cancers.
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| 3. |
- Backström, Eva
(author)
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Expression of stimulatory and inhibitory molecules in interactions between natural killer cells neurons
- 2003
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Doctoral thesis (other academic/artistic)abstract
- Natural killer (NK) cells are important effector cells of the innate and the early induced immune defense. In the nervous system they appear early during inflammation and have been ascribed a role in clearance of certain viral infections from the brain. NK cells are regulated by multiple signals transmitted via inhibitory and stimulatory receptors. In mice, they are inhibited by major histocompatibility complex (MHC) class I molecules and activated by retinoic acid early inducible gene-1 (RAE1), minor histocompatibility antigen H60 and the murine ULBP-like transcript 1 (MULT1) molecules, that are ligands for the stimulatory NKG2D receptor. The present thesis project was undertaken with the aim of elucidating whether neurons could be targets for an NK cell-mediated attack and the molecular mechanisms involved in an interaction between NK cells and neurons. Initial experiments were performed on embryonic mouse dorsal root ganglia (DRG) neurons in culture. Neurons exposed to syngeneic IL-2-activated NK cells were totally destroyed, leaving only remnants of neurons. The killing was cell contact- and perfor-independent and the neurons showed signs of apoptosis. Furthermore, the surrounding glial cells constituted protection against the NK cell-mediated degeneration of DRG neurons that was independent of MHC class I expression. In contrast to the complete destruction of the DRG neurons of the peripheral nervous system ventral spinal cord neurons and hippocampal neurons of the central nervous system were resistant to NK cell-mediated killing. The resistance to NK cell-mediated lysis of the latter neurons was not related to protection by MHC class I molecules, since MHC class I deficient neurons were equally resistant to lysis. Analysis of the expression of ligands for the activating receptor NKG2D revealed differential expression of RAE1 in the different populations of neurons, with high levels of both RAE1 transcripts and surface expression of NKG2D-binding proteins in the susceptible DRG neurons, while the expression of these molecules in the resistant hippocampal neurons was low. Furthermore, blocking antibodies against NKG2D inhibited the NK cell-mediated killing of DRG neurons. Expression of RAE1 has so far only been described in embryonic tissues. The results of our in vivo study showed that, RAE1 transcripts are expressed also in postnatal and young adult mice. Moreover, a peripheral nerve lesion of the sciatic nerve, resulted in an early reduction in expression of stimulatory RAE1 and MULT1 transcripts, followed by an increase in the expression of classical MHC class I transcripts compared to sham-operated control mice. hi addition, murine cytomegalovirus and influenza A virus infections of DRG neuronal cultures caused increased expression of transcripts encoding RAE1, MULT1 and classical MHC class I molecules. Interferon-gamma treatment of DRG neuronal cultures resulted in an increased expression of classical and non-classical MHC class I encoding transcripts. Treatment of the DRG neuronal cultures with retinoic acid receptor agonists did not affect the expression of transcripts of any of the investigated molecules. A two-compartment in vitro model was used to study whether interferon-gamma and influenza A virus added to the axonal compartment could affect the expression of molecules in the nerve cell body compartment. Exposure to both agents resulted in an increase in MHC class I expression in the nerve cell body compartment whereas the expression of RAE I and MULT1 was unaffected. In conclusion, this thesis provides further insight into the potential role of NK cells in diseases of the nervous system. The results show; that NK cells may induce degeneration of neurons that express ligands for the NK cell stimulatory receptor NKG2D, that transcripts for these ligands are expressed in the adult nervous system and that a peripheral nerve lesion, a viral infection and treatment with interferon-gamma can modify the expression of these ligands.
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| 4. |
- Backström, Eva, et al.
(author)
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Trash to Treasure : Microwave-Assisted Conversion of Polyethylene to Functional Chemicals
- 2017
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In: Industrial & Engineering Chemistry Research. - : American Chemical Society (ACS). - 0888-5885 .- 1520-5045. ; 56:50, s. 14814-14821
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Journal article (peer-reviewed)abstract
- An effective microwave-assisted process for recycling low-density polyethylene (LDPE) waste into value-added chemicals was developed. To achieve fast and effective oxidative degradation aimed at production of dicarboxylic acids, nitric acid was utilized as an oxidizing agent. Different conditions were evaluated, where recycling time and concentration of oxidizing agent were varied and the end products were characterized by FTIR, NMR, and HPLC. After just 1 h of microwave irradiation at 180 degrees C in relatively dilute nitric acid solution (0.1 g/mL), LDPE powder was totally degraded. This transformation led to few well-defined water-soluble products, mainly succinic, glutaric, and adipic acids, as well as smaller amounts of longer dicarboxylic acids, acetic acid, and propionic acid. The length of the obtained dicarboxylic acids could to some extent be tuned by adjusting the reaction time, temperature, and amount of oxidizing agent. Finally, the developed process was verified by recycling LDPE freezer bags as model LDPE waste. The freezer bags were converted mainly into dicarboxylic acids with a yield of 71%, and the carbon efficiency of the process was 37%. The developed method can, thus, contribute to a circular economy and offers new possibilities to increase the value of plastic waste.
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| 5. |
- Backström, Tobias, et al.
(author)
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Anaesthesia and handling stress effects on pigmentation and monoamines in Arctic charr
- 2017
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In: Environmental Biology of Fishes. - : Springer. - 0378-1909 .- 1573-5133. ; 100:5, s. 471-480
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Journal article (peer-reviewed)abstract
- Stress responsiveness differs between individuals and is often categorized into different stress coping styles. Using these stress coping styles for selection in fish farming could be beneficial, since stress is one main factor affecting welfare. In Arctic charr (Salvelinus alpinus) carotenoid pigmentation is associated with stress responsiveness and stress coping styles. Thus this could be an important tool to use for selection of stress resilient charr. However, anaesthetics seem to affect carotenoid pigmentation, and it would be better if the method for selection could be implemented during normal maintenance, which usually includes anaesthetics. Therefore, this study investigated how the use of anaesthetics affected carotenoid pigmentation, i.e. number of spots, over time compared to no-anaesthetic treatment. Additionally, the stress indicators monoamines and glucocorticoids were investigated. The results indicate that the anaesthetic MS-222 affects number of spots on the right side. This anaesthetic also increased dopaminergic activity in the telencephalon. Both brain dopaminergic and serotonergic activity was associated with spottiness. Further, behaviour during anaesthetization was associated with spots on the left side, but not the right side. Repetition of the same treatment seemed to affect spot numbers on the right side. In conclusion, this study shows that inducing stress in charr affects the carotenoid spots. Thus, it is possible to use anaesthetics when evaluating spottiness although careful planning is needed.
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| 6. |
- Backström, Tobias, et al.
(author)
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Dominance and stress signalling of carotenoid pigmentation in Arctic charr (Salvelinus alpinus): Lateralization effects?
- 2015
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In: Physiology and Behavior. - : Elsevier BV. - 0031-9384 .- 1873-507X. ; 138, s. 52-57
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Journal article (peer-reviewed)abstract
- Social conflicts are usually solved by agonistic interactions where animals use cues to signal dominance or subordinance. Pigmentation change is a common cue used for signalling. In our study, the involvement of carotenoid-based pigmentation in signalling was investigated in juvenile Arctic charr (Salvelinus alpinus). Size-matched pairs were analysed for pigmentation both before and after being tested for competitive ability. We found that dominant individuals had fewer carotenoid-based spots on the right and left sides as well as lower plasma cortisol levels compared to subordinate individuals. Further, the number of spots on both sides was positively associated with plasma cortisol levels. These results indicate that carotenoid-based pigmentation in Arctic charr signals dominance and stress coping style. Further, it also appears as if carotenoid-based pigmentation is lateralized in Arctic charr, and that the right side signals aggression and dominance whereas the left side signals stress responsiveness. (C) 2014 Elsevier Inc. All rights reserved.
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| 7. |
- Backström, Tobias, et al.
(author)
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Short-term stress: effects on cortisol levels and carotenoid spots in Arctic char (Salvelinus alpinus)
- 2016
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In: Canadian Journal of Zoology. - : Canadian Science Publishing. - 0008-4301 .- 1480-3283. ; 94, s. 707-712
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Journal article (peer-reviewed)abstract
- Earlier studies have shown that the carotenoid pigmentation in Arctic char (Salvelinus alpinus (L., 1758)) is connected to stress responsiveness. These studies also suggested that the pigmentation is dynamic and can change quickly. Therefore, we wanted to investigate the effect of a short-term stressor on the number of carotenoid spots before and after certain time intervals after the stressor. Individuals were exposed to a net-restraint stressor for 1 min and then assigned a recovery time of either 0, 1, 2, 8, or 24 h. Photographs were taken before the stressor and after the recovery time to count carotenoid spots and to look at the relative changes over time. Behaviour during the stressor and cortisol levels after the assigned recovery time were evaluated. We found that the change in spottiness, measured as the ratio of spots after and before the stressor, changed with recovery time on the right side but not on the left side. Furthermore, left-side spots were correlated with struggling activity. Thus, carotenoid pigmentation seems to be lateralized, with more static spots on the left side connected to stress responsiveness, whereas spots on the right side seem to be more dynamic.
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| 8. |
- Backström, Tobias, et al.
(author)
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Social stress effects on pigmentation and monoamines in Arctic charr
- 2015
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In: Behavioural Brain Research. - : Elsevier BV. - 0166-4328 .- 1872-7549. ; 291, s. 103-107
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Journal article (peer-reviewed)abstract
- Pigmentation often signals status and in general melanin-based pigmentation is indicative of aggression and stress resilience in vertebrates. This is evident in the salmonids Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss) where more melanin spotted individuals are more stress resilient. However, in the salmonid Arctic charr (Salvelinus alpinus) it seems as if it is carotenoid-based pigmentation that signals aggression and stress resilience. In our study, social stress effects on carotenoid-based spots, and behavioural and physiological stress responses were investigated. Socially stressed individuals have more spots, and behavioural stress responses were associated with spots. Some of the results concerning physiological stress responses, such as plasma cortisol levels and monoaminergic activity, are associated with spottiness. Further, the earlier proposed lateralization of spots, with left side connected to stress responsiveness and right side to aggression, is to some extent validated although not conclusively. In conclusion, this study provides further evidence that more stressed charr have more carotenoid spots, and for the first time monoaminergic activity is shown to be connected with carotenoid pigmentation.
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| 9. |
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| 10. |
- Backström, Tobias, et al.
(author)
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The effect of anesthetics on carotenoid pigmentation and behavior in Arctic char (Salvelinus alpinus)
- 2015
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In: Journal of Veterinary Behavior: Clinical Applications and Research. - : Elsevier BV. - 1558-7878 .- 1878-7517. ; 10, s. 179-184
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Journal article (peer-reviewed)abstract
- Status of individual animals is often shown in pigmentation. For instance, stress responsiveness is associated with melanin-based pigmentation in vertebrates in general. This pattern is evident in Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss), with melanin-based spots indicating stress coping style. Arctic char (Salvelinus alpinus) differ from other salmonids in pigmentation but have an association between carotenoid-based pigmentation and stress coping style. These pigmentation differences could be used as a fast and simple tool for improving breeding programs. However, the procedure for photographing individuals is stressful. Therefore, we wanted to investigate if 3 common inhalation anesthetics could be used to reduce the stress involved in the procedure compared to a no-anesthetics group. Behavior was also monitored during the anesthetization. All 3 anesthetics (Aquacalm, Benzocaine, and MS-222) differed in pigmentation compared to the no-anesthetics group by having a higher number of spots. In the anesthetic treatments as well as the no-anesthetics group, the fish had elevated plasma cortisol levels. In fact, the no-anesthetics group had higher cortisol than treated fish. This was probably because of procedural differences such as time affecting the stress response. Furthermore, in a long-term experiment, all fish survived and had similar condition factors 1 week after photographing as before. Therefore, the method for photographing Arctic char is deemed safe and could be used as a tool for estimating stress coping style, but careful planning is needed for experiments using it
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