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Sandholm, Kerstin
Publications (10 of 37) Show all publications
Fromell, K., Adler, A., Åman, A., Manivel, V. A., Huang, S., Duhrkop, C., . . . Nilsson, B. (2020). Assessment of the Role of C3(H2O) in the Alternative Pathway. Frontiers in Immunology, 11, 1-13, Article ID 530.
Open this publication in new window or tab >>Assessment of the Role of C3(H2O) in the Alternative Pathway
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2020 (English)In: Frontiers in Immunology, ISSN 1664-3224, E-ISSN 1664-3224, Vol. 11, p. 1-13, article id 530Article in journal (Refereed) Published
Abstract [en]

In this study we investigate the hydrolysis of C3 to C3(H2O) and its ability to initiate activation via the alternative pathway (AP) of the complement system. The internal thioester bond within C3 is hydrolyzed by water in plasma because of its inherent lability. This results in the formation of non-proteolytically activated C3(H2O) which is believed have C3b-like properties and be able to form an active initial fluid phase C3 convertase together with Factor B (FB). The generation of C3(H2O) occurs at a low but constant rate in blood, but the formation can be greatly accelerated by the interaction with various surfaces or nucleophilic and chaotropic agents. In order to more specifically elucidate the relevance of the C3(H2O) for AP activation, formation was induced in solution by repeated freeze/thawing, methylamine or KCSN treatment and named C3(x) where the x can be any of the reactive nucleophilic or chaotropic agents. Isolation and characterization of C3(x) showed that it exists in several forms with varying attributes, where some have more C3b-like properties and can be cleaved by Factor I in the presence of Factor H. However, in common for all these variants is that they are less active partners in initial formation of the AP convertase compared with the corresponding activity of C3b. These observations support the idea that formation of C3(x) in the fluid phase is not a strong initiator of the AP. It is rather likely that the AP mainly acts as an amplification mechanism of complement activation that is triggered by deposition of target-bound C3b molecules generated by other means.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2020
Keywords
complement, C3, C3(H2O), C3b, alternative pathway, C3 convertase
National Category
Immunology
Research subject
Biomedical Sciences, Immunology
Identifiers
urn:nbn:se:lnu:diva-94084 (URN)10.3389/fimmu.2020.00530 (DOI)000526750400001 ()32296436 (PubMedID)
Funder
Swedish Research Council, 2016-2075-5.1Swedish Research Council, 2016- 04519
Available from: 2020-05-05 Created: 2020-05-05 Last updated: 2020-05-05Bibliographically approved
Tjernberg, A. R., Woksepp, H., Sandholm, K., Johansson, M., Dahle, C., Ludvigsson, J. F., . . . Nilsson Ekdahl, K. (2020). Celiac disease and complement activation in response to Streptococcus pneumoniae. European Journal of Pediatrics, 179(1), 133-140
Open this publication in new window or tab >>Celiac disease and complement activation in response to Streptococcus pneumoniae
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2020 (English)In: European Journal of Pediatrics, ISSN 0340-6199, E-ISSN 1432-1076, Vol. 179, no 1, p. 133-140Article in journal (Refereed) Published
Abstract [en]

Individuals with celiac disease (CD) are at increased risk of invasive pneumococcal disease (IPD). The aim of this study was to explore whether the complement response to Streptococcus pneumoniae differed according to CD status, and could serve as an explanation for the excess risk of IPD in CD. Twenty-two children with CD and 18 controls, born 1999-2008, were included at Kalmar County Hospital, Sweden. The degree of complement activation was evaluated by comparing levels of activation products C3a and sC5b-9 in plasma incubated for 30 min with Streptococcus pneumoniae and in non-incubated plasma. Complement analyses were performed with enzyme-linked immunosorbent assay (ELISA). Pneumococcal stimulation caused a statistically significant increase in C3a as well as sC5b-9 in both children with CD and controls but there was no difference in response between the groups. After incubation, C3a increased on average 4.6 times and sC5b-9 22 times in both the CD and the control group (p = 0.497 and p = 0.724 respectively). Conclusion: Complement response to Streptococcus pneumoniae seems to be similar in children with and without CD and is thus unlikely to contribute to the increased susceptibility to invasive pneumococcal disease in CD.

Place, publisher, year, edition, pages
Springer, 2020
Keywords
Coeliac, Pneumococcal, Infection, Innate immunity, MBL
National Category
Immunology
Research subject
Biomedical Sciences, Immunology
Identifiers
urn:nbn:se:lnu:diva-90197 (URN)10.1007/s00431-019-03490-w (DOI)000494392200001 ()31691001 (PubMedID)
Available from: 2019-11-21 Created: 2019-11-21 Last updated: 2020-03-11Bibliographically approved
Carlsson, H., Sandholm, K., Haddish, H. W., Brudin, L., Nilsson Ekdahl, K. & Tjernberg, I. (2020). Complement activation in individuals with previous subclinical Lyme borreliosis and patients with previous Lyme neuroborreliosis. European Journal of Clinical Microbiology and Infectious Diseases, 39(5), 855-862
Open this publication in new window or tab >>Complement activation in individuals with previous subclinical Lyme borreliosis and patients with previous Lyme neuroborreliosis
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2020 (English)In: European Journal of Clinical Microbiology and Infectious Diseases, ISSN 0934-9723, E-ISSN 1435-4373, Vol. 39, no 5, p. 855-862Article in journal (Refereed) Published
Abstract [en]

Lyme borreliosis (LB) is caused by Borrelia burgdorferi and infection may lead to not only a large variety of clinical manifestations but also a subclinical outcome. The aim of the present study was to investigate if there is a constitutional difference in complement activation between individuals with previous subclinical Lyme borreliosis (SB) and patients previously diagnosed with Lyme neuroborreliosis (LNB).

Lepirudin plasma for activation studies was collected from 60 SB individuals and from 22 patients pre-diagnosed with LNB. The plasma was incubated with live Borrelia spirochetes of two strains (complement sensitive B. garinii Lu59 and complement resistant B. afzelii ACA1).

Complement factor C3 was measured in non-activated lepirudin plasma with immune-nephelometry and C3a and sC5b-9 generated during complement activation were measured by enzyme-linked immunosorbent assay.

We found that the complement sensitive Lu59 induced higher complement activation than the complement resistant ACA1 when measuring activation products C3a and sC5b-9 in SB and LNB patients, p < 0.0001. No significant difference was found between SB and LNB patients in systemic levels of C3. Furthermore, SB individuals generated a higher activation of C3 cleavage to C3a (C3a/C3 ratio) than LNB patients after activation with ACA1, p < 0.001, but no significant differences were found in response to Lu59. In conclusion, Lu59 induced higher complement activation than ACA1 and individuals with previous SB showed increased generation of C3a compared with patients with previous LNB. In our study population, this mechanism could lead to less elimination of spirochetes in LNB patients and thereby be a factor contributing to the clinical outcome.

Place, publisher, year, edition, pages
Springer, 2020
Keywords
Complement activation, Subclinical Lyme borreliosis, Lyme neuroborreliosis, Lyme borreliosis, Innate immune system, C3a
National Category
Infectious Medicine
Research subject
Natural Science, Biomedical Sciences
Identifiers
urn:nbn:se:lnu:diva-93736 (URN)10.1007/s10096-019-03807-5 (DOI)000528380400006 ()31893341 (PubMedID)
Available from: 2020-04-28 Created: 2020-04-28 Last updated: 2020-05-18Bibliographically approved
Sandholm, K., Carlsson, H., Persson, B., Skattum, L., Tjernberg, I., Nilsson, B. & Nilsson Ekdahl, K. (2020). Discrepancies in plasma levels of complement components measured by a newly introduced commercially available magnetic bead technique compared to presently available clinical reference intervals [Letter to the editor]. Scandinavian Journal of Immunology, 91(2), 1-3, Article ID e12831.
Open this publication in new window or tab >>Discrepancies in plasma levels of complement components measured by a newly introduced commercially available magnetic bead technique compared to presently available clinical reference intervals
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2020 (English)In: Scandinavian Journal of Immunology, ISSN 0300-9475, E-ISSN 1365-3083, Vol. 91, no 2, p. 1-3, article id e12831Article in journal, Letter (Refereed) Published
Place, publisher, year, edition, pages
John Wiley & Sons, 2020
National Category
Immunology
Research subject
Biomedical Sciences, Immunology; Biomedical Sciences, Immunology
Identifiers
urn:nbn:se:lnu:diva-90503 (URN)10.1111/sji.12831 (DOI)000497171700001 ()31536648 (PubMedID)
Available from: 2019-12-13 Created: 2019-12-13 Last updated: 2020-03-11Bibliographically approved
Mohebnasab, M., Eriksson, O., Persson, B., Sandholm, K., Mohlin, C., Huber-Lang, M., . . . Nilsson, B. (2019). Current and Future Approaches for Monitoring Responses to Anti-complement Therapeutics. Frontiers in Immunology, 10, 1-13, Article ID 2539.
Open this publication in new window or tab >>Current and Future Approaches for Monitoring Responses to Anti-complement Therapeutics
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2019 (English)In: Frontiers in Immunology, ISSN 1664-3224, E-ISSN 1664-3224, Vol. 10, p. 1-13, article id 2539Article, review/survey (Refereed) Published
Abstract [en]

Aberrations in complement system functions have been identified as either direct or indirect pathophysiological mechanisms in many diseases and pathological conditions, such as infections, autoimmune diseases, inflammation, malignancies, and allogeneic transplantation. Currently available techniques to study complement include quantification of (a) individual complement components, (b) complement activation products, and (c) molecular mechanisms/function. An emerging area of major interest in translational studies aims to study and monitor patients on complement regulatory drugs for efficacy as well as adverse events. This area is progressing rapidly with several anti-complement therapeutics under development, in clinical trials, or already in clinical use. In this review, we summarized the appropriate indications, techniques, and interpretations of basic complement analyses, exemplified by a number of clinical disorders.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2019
Keywords
clinical trial, laboratory investigation, immunoassays, functional assays, CV%
National Category
Immunology
Research subject
Biomedical Sciences, Immunology
Identifiers
urn:nbn:se:lnu:diva-90506 (URN)10.3389/fimmu.2019.02539 (DOI)000498927000001 ()31787968 (PubMedID)
Available from: 2019-12-12 Created: 2019-12-12 Last updated: 2019-12-12Bibliographically approved
Sandholm, K. (2019). Development and evaluation of immunoassays for complement diagnostics. (Doctoral dissertation). Växjö: Linnaeus University Press
Open this publication in new window or tab >>Development and evaluation of immunoassays for complement diagnostics
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Laboratory analyses of human body fluids play an important role in clinical diagnosis. This thesis comprises projects in which various immune assays have been developed and evaluated as complement diagnostics in both plasma and cerebrospinal fluid (CSF). Various methods have been used, such as ELISA, Western blot, flow cytometry, and xMAP technology.

In paper 1, we monitored complement parameters in EDTA-plasma and CSF from patients with suspected neuroborreliosis (NB) by using in-house sandwich ELISAs.  We found significantly elevated levels of C1q, C4, C3, and C3a in CSF, but not in plasma, suggesting that complement plays a role in the intrathecal immune response in NB.

Complement is a main player in early inflammation, and in paper 2, we investigated the role of complement activation in phagocytosis and the release of cytokines and chemokines in response to two clinical isolates: Borrelia afzelii K78 and Borrelia garinii LU59. Our results show that complement activation plays an important role in the initial process of phagocytosis, but not in the subsequent cytokine release that occurs in response to live Borrelia spirochetes. C1q, a valuable biomarker of disease activity in systemic lupus erythematosus (SLE), can be quantitated using a number of different immunochemical techniques.

In paper 3, we developed and validated a magnetic bead-based immunoassay for quantifying C1q in EDTA-plasma and CSF. In contrast to soluble immunoprecipitation assays such as nephelometry and turbidimetry, this new assay was not hampered by the interaction between C1q and detecting antibodies. The novel assay was shown to give a clear correlation between nephritis and SLEDAI score in SLE.

Warfarin is a commonly used but complicated treatment in patients with thrombosis. It reduces the function of vitamin K-dependent coagulation proteins, including protein S, which is a ligand for C4b-binding protein (C4BP). In paper 4, we demonstrated a decrease in various isoforms of C4BP that resulted in a strong complement activation in patients treated with warfarin, but not in patients treated with other anticoagulants.

Taken together, the results from the papers included in this thesis stress the importance of validated assays with high sensitivity and specificity in enabling accurate diagnosis in patients with various inflammatory diseases.

Place, publisher, year, edition, pages
Växjö: Linnaeus University Press, 2019. p. 58
Series
Linnaeus University Dissertations ; 369
Keywords
Immune assays, complement diagnostics, xMAP-technology, C1q, preanalytical factors, method validation
National Category
Immunology in the medical area
Research subject
Biomedical Sciences, Immunology
Identifiers
urn:nbn:se:lnu:diva-90125 (URN)978-91-89081-14-7 (ISBN)978-91-89081-15-4 (ISBN)
Public defence
2019-12-12, Azur, Hus Vita, Universitetskajen, Kalmar, 09:15 (Swedish)
Opponent
Supervisors
Available from: 2019-11-17 Created: 2019-11-15 Last updated: 2020-04-07Bibliographically approved
Sandholm, K., Persson, B., Skattum, L., Eggertsen, G., Nyman, D., Gunnarsson, I., . . . Nilsson Ekdahl, K. (2019). Evaluation of a Novel Immunoassay for Quantification of C1q for Clinical Diagnostic Use. Frontiers in Immunology, 10, Article ID 7.
Open this publication in new window or tab >>Evaluation of a Novel Immunoassay for Quantification of C1q for Clinical Diagnostic Use
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2019 (English)In: Frontiers in Immunology, ISSN 1664-3224, E-ISSN 1664-3224, Vol. 10, article id 7Article in journal (Refereed) Published
Abstract [en]

Objectives: C1q is a valuable biomarker of disease activity in systemic lupus erythematosus (SLE). The "gold standard" assay, rocket immunoelectrophoresis (RIE), is time-consuming, and thus a shift to soluble immune precipitation techniques such as nephelometry has occurred. However, quantification of C1q with these techniques has been questioned as a result of the antibody binding properties of C1q. In the present work, we have compared results using various techniques (RIE, nephelometry, and ELISA) and have developed and validated a new magnetic bead-based sandwich immunoassay (MBSI). Methods: C1q was quantified by nephelometry and the new sandwich immunoassay in 45 serum samples analyzed using RIE. C1q was also assessed in plasma using RIE and sandwich immunoassay in samples from SLE patients with nephritis (n = 69), SLE patients without nephritis (n = 310) as classified by BILAG score, and matched controls (n = 322). In addition, cerebrospinal fluid (CSF) samples from 31 patients, previously analyzed with ELISA, were also analyzed with the MBSI to test the behavior of this new assay in the lower detection range. Results: We found a strong correlation between the new MBSI, RIE, and ELISA, but not with nephelometry. The MBSI demonstrated lower levels of C1q in SLE patients than in matched controls (p < 0.0001), and patients with nephritis had lower levels than patients without nephritis (p < 0.01). Similarily, RIE showed significant differences between the patient groups (p < 0.0001). An association was also found between the levels of C1q and the SLE disease activity index (SLEDAI). Furthermore, there was good correlation between the values obtained by MBSI and ELISA, in both serum (r = 0.960) and CSF (r = 0.786), underscoring the ability of both techniques to measure low concentrations of C1q with high accuracy. Conclusion: The sandwich immunoassay correlated well with RIE, but soluble immune precipitation techniques, such as nephelometry, did not appear suitable alternatives, since C1q itself, and possibly anti-C1q antibodies, interfered with the measurements. The new sandwich immunoassay is therefore a good replacement for RIE in monitoring SLE disease activity.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2019
Keywords
C1q, immunoassays, plasma, CSF, SLE, nephritis
National Category
Immunology Rheumatology and Autoimmunity
Research subject
Biomedical Sciences, Immunology
Identifiers
urn:nbn:se:lnu:diva-80277 (URN)10.3389/fimmu.2019.00007 (DOI)000456846400001 ()2-s2.0-85061243783 (Scopus ID)
Available from: 2019-02-07 Created: 2019-02-07 Last updated: 2019-11-12Bibliographically approved
Nilsson Ekdahl, K., Mohlin, C., Adler, A., Aman, A., Manivel, V. A., Sandholm, K., . . . Nilsson, B. (2019). Is generation of C-3(H2O) necessary for activation of the alternative pathway in real life?. Paper presented at 17th European Meeting on Complement in Human Disease (EMCHD), 2019, Madrid, SPAIN. Molecular Immunology, 114, 353-361
Open this publication in new window or tab >>Is generation of C-3(H2O) necessary for activation of the alternative pathway in real life?
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2019 (English)In: Molecular Immunology, ISSN 0161-5890, E-ISSN 1872-9142, Vol. 114, p. 353-361Article in journal (Refereed) Published
Abstract [en]

In the alternative pathway (AP) an amplification loop is formed, which is strictly controlled by various fluid-phase and cell-bound regulators resulting in a state of homeostasis. Generation of the "C3b-like" C3(H2O) has been described as essential for AP activation, since it conveniently explains how the initial fluid-phase AP convertase of the amplification loop is generated. Also, the AP has a status of being an unspecific pathway despite thorough regulation at different surfaces. During complement attack in pathological conditions and inflammation, large amounts of C3b are formed by the classical/lectin pathway (CP/LP) convertases. After the discovery of LP's recognition molecules and its tight interaction with the AP, it is increasingly likely that the AP acts in vivo mainly as a powerful amplification mechanism of complement activation that is triggered by previously generated C3b molecules initiated by the binding of specific recognition molecules. Also in many pathological conditions caused by a dysregulated AP amplification loop such as paroxysmal nocturnal hemoglobulinuria (PNH) and atypical hemolytic uremic syndrome (aHUS), C3b is available due to minute LP and CP activation and/or generated by non-complement proteases. Therefore, C3(H2O) generation in vivo may be less important for AP activation during specific attack or dysregulated homeostasis, but may be an important ligand for C3 receptors in cell-cell interactions and a source of C3 for the intracellular complement reservoir.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Complement system, C-3(H2O), Conformation, Analysis, Proteases, Alternative pathway
National Category
Immunology
Research subject
Biomedical Sciences, Immunology
Identifiers
urn:nbn:se:lnu:diva-89867 (URN)10.1016/j.molimm.2019.07.032 (DOI)000490625600041 ()31446306 (PubMedID)
Conference
17th European Meeting on Complement in Human Disease (EMCHD), 2019, Madrid, SPAIN
Available from: 2019-10-31 Created: 2019-10-31 Last updated: 2019-10-31Bibliographically approved
Mohlin, C., Sandholm, K., Kvanta, A., Nilsson Ekdahl, K. & Johansson, K. (2018). A model to study complement involvement in experimental retinal degeneration.. Upsala Journal of Medical Sciences, 123(1), 28-42
Open this publication in new window or tab >>A model to study complement involvement in experimental retinal degeneration.
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2018 (English)In: Upsala Journal of Medical Sciences, ISSN 0300-9734, E-ISSN 2000-1967, Vol. 123, no 1, p. 28-42Article in journal (Refereed) Published
Abstract [en]

BACKGROUND: The complement system (CS) plays a role in the pathogenesis of a number of ocular diseases, including diabetic retinopathy (DR), glaucoma, uveitis, and age-related macular degeneration (AMD). Given that many of the complex eye-related degenerative diseases have limited treatment opportunities, we aimed to mimic the in vivo retinal degenerative process by developing a relevant co-culture system.

METHOD AND MATERIALS: The adult porcine retina was co-cultured with the spontaneously arising human retinal pigment epithelial cells-19 (ARPE-19).

RESULTS: Inflammatory activity was found after culture and included migrating microglial cells, gliosis, cell death, and CS activation (demonstrated by a minor increase in the secreted anaphylotoxin C3a in co-culture). CS components, including C1q, C3, C4, soluble C5b-9, and the C5a receptor, were expressed in the retina and/or ARPE cells after culture. C1q, C3, and CS regulators such as C4 binding protein (C4BP), factor H (CFH), and factor I (CFI) were secreted after culture.

DISCUSSION: Thus, our research indicates that this co-culturing system may be useful for investigations of the CS and its involvement in experimental neurodegenerative diseases.

Place, publisher, year, edition, pages
Taylor & Francis, 2018
Keywords
AMD, RPE, complement system, ocular diseases, retina
National Category
Immunology in the medical area
Research subject
Biomedical Sciences, Immunology
Identifiers
urn:nbn:se:lnu:diva-71489 (URN)10.1080/03009734.2018.1431744 (DOI)000428060300004 ()29436895 (PubMedID)2-s2.0-85041902488 (Scopus ID)
Available from: 2018-03-12 Created: 2018-03-12 Last updated: 2019-08-29Bibliographically approved
Labriere, C., Kondori, N., Caous, J. S., Boomgaren, M., Sandholm, K., Nilsson Ekdahl, K., . . . Svenson, J. (2018). Development and evaluation of cationic amphiphilic antimicrobial 2,5-diketopiperazines. Paper presented at 7th International Meeting on Antimicrobial Peptides, AUG 25-27, 2017, Univ Copenhagen, Copenhagen, DENMARK. Journal of Peptide Science, 24(7), Article ID UNSP e3090.
Open this publication in new window or tab >>Development and evaluation of cationic amphiphilic antimicrobial 2,5-diketopiperazines
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2018 (English)In: Journal of Peptide Science, ISSN 1075-2617, E-ISSN 1099-1387, Vol. 24, no 7, article id UNSP e3090Article in journal (Refereed) Published
Abstract [en]

Both pathogenic bacteria and fungi are developing resistance to common antimicrobial treatment at an alarming rate. To counteract this development, it is of essence to develop new classes of antimicrobial agents. One such class is antimicrobial peptides, most of which are derived from the innate immune system. In this study, a series of novel 2,5-diketopiperazines were designed, synthesized, and evaluated for their antimicrobial abilities. The compounds were designed to probe the pharmacophore dictated for short linear mimics of antimicrobial cationic peptides, and as such, the compounds contain a range of cationic and hydrophobic functionalities. Several of the prepared compounds displayed high antimicrobial activities toward bacteria and also against human pathogenic fungi. Of particular interest was the high activity toward fungal strains with an inherent increased resistance toward conventional antifungal agents. The most effective compounds displayed inhibition of Candida glabrata and Candida krusei growth at concentrations between 4 and 8 mu g/mL, which is comparable to commercial antifungal agents in use. Structure activity relationship studies revealed a similar dependence on cationic charge and the volume of the hydrophobic bulk as for linear cationic antimicrobial peptides. Finally, the hemolytic activity of selected compounds was evaluated, which revealed a potential to produce active compounds with attenuation of unwanted hemolysis. The findings highlight the potential of cyclic cationic amphiphilic peptidomimetics as a class of promising compounds for the treatment of infections caused by microorganisms with an increased resistance to conventional antimicrobial agents.

Place, publisher, year, edition, pages
John Wiley & Sons, 2018
Keywords
2, 5-diketopiperazine, antifungal agents, antimicrobial, Candida krusei, MRSA, structure-activity relationship
National Category
Biochemistry and Molecular Biology
Research subject
Natural Science, Biomedical Sciences
Identifiers
urn:nbn:se:lnu:diva-77499 (URN)10.1002/psc.3090 (DOI)000440144700005 ()29845683 (PubMedID)2-s2.0-85047664224 (Scopus ID)
Conference
7th International Meeting on Antimicrobial Peptides, AUG 25-27, 2017, Univ Copenhagen, Copenhagen, DENMARK
Available from: 2018-08-31 Created: 2018-08-31 Last updated: 2019-08-29Bibliographically approved
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