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Mahittikorn A, Kwankaew P, Rattaprasert P, Kotepui KU, Masangkay FR, Kotepui M. Elevation of serum interleukin-1β levels as a potential indicator for malarial infection and severe malaria: a meta-analysis. Malar J 2022; 21:308. [PMID: 36309676 PMCID: PMC9617441 DOI: 10.1186/s12936-022-04325-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Accepted: 10/18/2022] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Interleukin (IL)-1β is a proinflammatory cytokine that has a role in disease-related inflammation, including malaria. However, reports on the effect of IL-1β on malaria severity are inconsistent. Therefore, meta-analyses to compare differences in IL-1β levels between patients with severe malaria, patients with uncomplicated malaria and healthy controls were performed. METHODS The PRISMA standards were used to perform a systematic review and meta-analysis. A search of PubMed, Scopus, EMBASE and reference lists was conducted for articles providing data on IL-1β levels between patients with severe malaria, patients with uncomplicated malaria and healthy controls between January 1988 and March 2022, using a combination of search terms. The quality of all studies included in this review was determined using the Strengthening the Reporting of Observational Studies in Epidemiology statement: guidelines for reporting observational studies. The evidence was synthesized quantitatively and qualitatively. The differences in IL-1 levels across participant groups were recounted narratively for qualitative synthesis. For quantitative synthesis, the mean difference in IL-1β levels across groups of participants was calculated using a random effects meta-analysis. The publication bias was assessed using funnel plots, Egger's test and a contour-enhanced funnel plot. RESULTS A total of 1281 articles were discovered, and the 17 that satisfied the inclusion criteria were included for syntheses. The meta-analysis results using data from 555 cases of severe malaria and 1059 cases of uncomplicated malaria showed that severe malaria had a higher mean of IL-1β levels than uncomplicated malaria (P < 0.01, pooled mean difference: 1.92 pg/mL, 95% confidence interval: 0.60-3.25 pg/mL, I2: 90.41%, 6 studies). The meta-analysis results using data from 542 cases of uncomplicated malaria and 455 healthy controls showed no difference in mean IL-1β levels between the two groups (P = 0.07, pooled mean difference: 1.42 pg/mL, 95% confidence interval: - 0.1-2.94 pg/mL, I2: 98.93%, 6 studies). CONCLUSION The results from the meta-analysis revealed that IL-1β levels were higher in patients with severe malaria than in patients with uncomplicated malaria; however, IL-1β levels were similar in patients with uncomplicated malaria and healthy controls. Based on the limitations of the number of studies included in the meta-analysis and high levels of heterogeneity, further studies are needed to conclude that differences in IL-1β levels can be useful for monitoring the malaria severity.
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Affiliation(s)
- Aongart Mahittikorn
- Department of Protozoology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Pattamaporn Kwankaew
- Medical Technology, School of Allied Health Sciences, Walailak University, Tha Sala, Nakhon Si Thammarat, Thailand
| | - Pongruj Rattaprasert
- Department of Protozoology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Kwuntida Uthaisar Kotepui
- Medical Technology, School of Allied Health Sciences, Walailak University, Tha Sala, Nakhon Si Thammarat, Thailand
| | - Frederick Ramirez Masangkay
- Department of Medical Technology, Faculty of Pharmacy, Royal and Pontifical University of Santo Tomas, Manila, Philippines
| | - Manas Kotepui
- Medical Technology, School of Allied Health Sciences, Walailak University, Tha Sala, Nakhon Si Thammarat, Thailand
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Kotepui KU, Thirarattanasunthon P, Rattaprasert P, Kotepui M. A systematic review and meta-analysis of blood interleukin-4 levels concerning malaria infection and severity. Malar J 2022; 21:217. [PMID: 35820892 PMCID: PMC9277793 DOI: 10.1186/s12936-022-04237-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 06/30/2022] [Indexed: 11/16/2022] Open
Abstract
Background Interleukin (IL)-4 had been linked to malaria severity, but the findings are controversial, and the evidence is inconsistent and imprecise. In the current investigation, data on IL-4 levels in patients with severe and uncomplicated malaria were compiled. Methods The systematic review was registered at PROSPERO (CRD42022323387). Searches for relevant articles on IL-4 levels in patients with severe malaria and studies that examined IL-4 levels in both uncomplicated malaria and healthy controls were performed in PubMed, Embase, and Scopus using the search strategy without limitation to publication years or language. The quality of all included studies was evaluated using The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement: standards for reporting observational studies. Qualitative and quantitative data syntheses were performed. The random-effects model, which weights each study according to its between- and within-study variance, was used to pool the mean difference (MD) of individual studies. The degree of heterogeneity was determined using Cochran's Q and I2 statistics. Additionally, meta-regression and subgroup analyses were perfomed to investigate possible sources of heterogeneity. The outliers were identified using the leave-one-out method and assessed publication bias using funnel plots, Egger’s test, and a contour-enhanced funnel plot. Results A total of 2300 studies were identified through database searches, and 36 were included for analyses. The meta-analysis results showed lower mean IL-4 levels in severe malaria (434 cases) than in uncomplicated malaria (611 cases) (P = 0.01, pooled MD: −3.36 pg/mL, 95% confidence intervals CI −5.55 to −1.16 pg/mL, I2: 98.15%, 11 studies). The meta-analysis results showed no difference in mean IL-4 levels between cerebral malaria (96 cases) and noncerebral severe malaria (108 cases) (P = 0.71, pooled MD: 0.86 pg/mL, 95% CI −3.60 to 5.32 pg/mL, I2 92.13%, four studies). Finally, no difference was found in mean IL-4 levels between uncomplicated malaria (635 cases) and healthy controls (674 cases) (P = 0.57, pooled MD: 0.79 pg/mL, 95% CI −1.92 to 3.50 pg/mL, I2: 99.89%, 11 studies). Conclusion The meta-analysis revealed lower IL-4 levels in patients with severe malaria than in those with uncomplicated malaria, though a trend toward comparable IL-4 levels between both groups was more likely because several sources of heterogeneities were observed. Based on the limited number of studies included in the meta-analysis, until additional investigations have been conducted, IL-4 consideration as an alternative prognostic factor for malaria severity is not warranted. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04237-z.
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Affiliation(s)
- Kwuntida Uthaisar Kotepui
- Medical Technology Program, School of Allied Health Sciences, Walailak University, Tha Sala, Nakhon Si Thammarat, Thailand
| | - Phiman Thirarattanasunthon
- Public Health Program, School of Public Health, Walailak University, Tha Sala, Nakhon Si Thammarat, Thailand
| | - Pongruj Rattaprasert
- Department of Protozoology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Manas Kotepui
- Medical Technology Program, School of Allied Health Sciences, Walailak University, Tha Sala, Nakhon Si Thammarat, Thailand.
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Wilairatana P, Mala W, Milanez GDJ, Masangkay FR, Kotepui KU, Kotepui M. Increased interleukin-6 levels associated with malaria infection and disease severity: a systematic review and meta-analysis. Sci Rep 2022; 12:5982. [PMID: 35396564 PMCID: PMC8993930 DOI: 10.1038/s41598-022-09848-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 03/29/2022] [Indexed: 01/18/2023] Open
Abstract
Interleukin-6 (IL-6) is generated by immune cells during infection with malaria parasites and they are associated with the immunopathogenesis of malaria. The present systematic review and meta-analysis aimed to compare the differences in IL-6 levels between several groups of patients with malaria and healthy control groups. The systematic review was registered at PROSPERO with a registration number: CRD42021290753. Systematic literature searches were conducted in PubMed, Web of Science, and Scopus until November 7, 2021 to obtain studies that documented IL-6 levels in patients with malaria. The quality of the included studies was assessed using critical appraisal tools from the Joanna Briggs Institute. Differences in the mean IL-6 levels among patients with: (1) severe and non-severe malaria, (2) uncomplicated malaria and controls, (3) uncomplicated and asymptomatic malaria, (4) asymptomatic malaria and healthy controls, and (5) those that died or survived were estimated using a random-effects model. Forty-three of 1,969 studies were included in the systematic review. Results of the meta-analysis showed that patients with severe malaria had higher mean IL-6 levels than those with non-severe malaria [P = 0.04, weight mean difference (WMD) = 96.63 pg/mL, 95% confidence interval (CI) = 0.88 − 19.38 pg/mL, I2 = 99.9%, 13 studies]. Patients with uncomplicated malaria had higher mean IL-6 levels than the controls (P < 0.001, WMD = 42.86 pg/mL, 95% CI = 30.17 − 55.56 pg/mL, I2 = 100%, 17 studies). No differences in the mean levels of IL-6 were found between patients with uncomplicated malaria and those with asymptomatic malaria (P = 0.063, WMD = 42.07 pg/mL, 95% CI = − 2.23 pg/mL to − 86.37 pg/mL, I2 = 99.1%, 8 studies), or between patients with asymptomatic malaria and healthy controls (P = 0.45, WMD = 1.67 pg/mL, 95% CI = − 2.73 pg/mL to − 6.07 pg/mL, I2 = 98.1%, 2 studies). A higher mean level of IL-6 was observed in patients who died compared with the levels of those who survived (P = 0.007, WMD = 1,399.19 pg/mL, 95% CI = 384.16 − 2,414.2 pg/mL, I2 = 93.1%, 4 studies). Our meta-analysis of the pooled evidence can be used to guide future studies in which IL-6 levels are measured during malaria outbreaks to monitor malaria severity. Heterogeneity of the effect estimate among the included studies was the main limitation of this analysis. In conclusion, significantly increased levels of IL-6 were observed in patients with severe malaria compared with those in patients with non-severe malaria, which indicates that IL-6 is a candidate marker for severe malaria. Future studies should investigate the sensitivity and specificity of increased IL-6 levels to determine the effectiveness of assessments of IL-6 levels monitoring of malaria infection and severity.
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Affiliation(s)
- Polrat Wilairatana
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Wanida Mala
- Medical Technology, School of Allied Health Sciences, Walailak University, Tha Sala, Nakhon Si Thammarat, Thailand
| | - Giovanni De Jesus Milanez
- Department of Medical Technology, Faculty of Pharmacy, University of Santo Tomas, Manila, Philippines
| | | | - Kwuntida Uthaisar Kotepui
- Medical Technology, School of Allied Health Sciences, Walailak University, Tha Sala, Nakhon Si Thammarat, Thailand
| | - Manas Kotepui
- Medical Technology, School of Allied Health Sciences, Walailak University, Tha Sala, Nakhon Si Thammarat, Thailand.
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Immunosuppression in Malaria: Do Plasmodium falciparum Parasites Hijack the Host? Pathogens 2021; 10:pathogens10101277. [PMID: 34684226 PMCID: PMC8536967 DOI: 10.3390/pathogens10101277] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/27/2021] [Accepted: 09/28/2021] [Indexed: 12/13/2022] Open
Abstract
Malaria reflects not only a state of immune activation, but also a state of general immune defect or immunosuppression, of complex etiology that can last longer than the actual episode. Inhabitants of malaria-endemic regions with lifelong exposure to the parasite show an exhausted or immune regulatory profile compared to non- or minimally exposed subjects. Several studies and experiments to identify and characterize the cause of this malaria-related immunosuppression have shown that malaria suppresses humoral and cellular responses to both homologous (Plasmodium) and heterologous antigens (e.g., vaccines). However, neither the underlying mechanisms nor the relative involvement of different types of immune cells in immunosuppression during malaria is well understood. Moreover, the implication of the parasite during the different stages of the modulation of immunity has not been addressed in detail. There is growing evidence of a role of immune regulators and cellular components in malaria that may lead to immunosuppression that needs further research. In this review, we summarize the current evidence on how malaria parasites may directly and indirectly induce immunosuppression and investigate the potential role of specific cell types, effector molecules and other immunoregulatory factors.
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Almeida AC, Elias ABR, Marques MP, de Melo GC, da Costa AG, Figueiredo EFG, Brasil LW, Rodrigues-Soares F, Monteiro WM, de Lacerda MVG, Lanchote VL, Suarez-Kurtz G. Impact of Plasmodium vivax malaria and antimalarial treatment on cytochrome P450 activity in Brazilian patients. Br J Clin Pharmacol 2020; 87:1859-1868. [PMID: 32997351 DOI: 10.1111/bcp.14574] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 09/02/2020] [Accepted: 09/15/2020] [Indexed: 12/26/2022] Open
Abstract
AIMS To investigate the impact of Plasmodium vivax malaria and chloroquine-primaquine chemotherapy on CYP2D6 and CYP2C19 activity in patients from the Brazilian Amazon. METHODS Adult patients (n = 30) were given subtherapeutic doses of CYP2D6 and CYP2C19 phenotypic probes metoprolol (10 mg) and omeprazole (2 mg) in three different stages of vivax malaria illness: acute disease (study phase 1), post chemotherapy (phase 2) and convalescence (stage 3). Plasma concentrations of probes and CYP-hydroxylated metabolites (α-OH metoprolol and 5-OH omeprazole) were measured using LC/MS/MS. Two pharmacokinetic metrics were used to estimate CYP activity: (a) ratio of plasma concentrations of probe/metabolite at 240 minutes after administration of the probes and (b) ratio of areas under the time-concentration curves for probe/metabolite (AUC0-12h ). For statistical analysis, the pharmacokinetic metrics were normalized to the respective values in phase 3. Taqman assays were used for CYP2D6 and CYP2C19 genotyping. Cytokines levels were measured using cytometric bead array. RESULTS Both pharmacokinetic metrics for metoprolol and omeprazole, and plasma concentrations of cytokines IL-6, IL-8 and IL-10 varied significantly across the three study phases (ANOVA P < 0.0001). Post hoc tests showed greater metoprolol:α-OH metoprolol ratios in phases 1 and 2 compared to phase 3, larger omeprazole:5-OH omeprazole ratios in phase 1 than in phases 2 and 3, and higher circulating IL-6, IL-8 and IL-10 in phase 1 than in phases 2 and 3. CONCLUSION P. vivax malaria and treatment altered CYP2D6 and CYP2C19 metabolic phenotypes. CYP2C19 inhibition is attributed to a higher level of circulating proinflammatory cytokines, while suppression of CYP2D6 is ascribed mainly to chloroquine exposure.
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Affiliation(s)
- Anne Cristine Almeida
- Gerência de Malária, Fundação de Medicina Tropical Dr. Heitor Vieira Dourado, Manaus, Amazonas, Brazil.,Programa de Pós-graduação em Medicina Tropical, Universidade do Estado do Amazonas, Manaus, Amazonas, Brazil
| | | | - Maria Paula Marques
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Gisely Cardoso de Melo
- Gerência de Malária, Fundação de Medicina Tropical Dr. Heitor Vieira Dourado, Manaus, Amazonas, Brazil.,Programa de Pós-graduação em Medicina Tropical, Universidade do Estado do Amazonas, Manaus, Amazonas, Brazil
| | - Allyson Guimarães da Costa
- Programa de Pós-graduação em Medicina Tropical, Universidade do Estado do Amazonas, Manaus, Amazonas, Brazil.,Departamento de Pesquisa, Fundação Hospitalar de Hematologia e Hemoterapia do Amazonas, Manaus, Amazonas, Brazil
| | - Erick Frota Gomes Figueiredo
- Gerência de Malária, Fundação de Medicina Tropical Dr. Heitor Vieira Dourado, Manaus, Amazonas, Brazil.,Programa de Pós-graduação em Medicina Tropical, Universidade do Estado do Amazonas, Manaus, Amazonas, Brazil
| | - Larissa Wanderley Brasil
- Gerência de Malária, Fundação de Medicina Tropical Dr. Heitor Vieira Dourado, Manaus, Amazonas, Brazil.,Programa de Pós-graduação em Medicina Tropical, Universidade do Estado do Amazonas, Manaus, Amazonas, Brazil
| | - Fernanda Rodrigues-Soares
- Departamento de Patologia, Genética e Evolução, Universidade Federal do Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Wuelton Marcelo Monteiro
- Gerência de Malária, Fundação de Medicina Tropical Dr. Heitor Vieira Dourado, Manaus, Amazonas, Brazil.,Programa de Pós-graduação em Medicina Tropical, Universidade do Estado do Amazonas, Manaus, Amazonas, Brazil
| | - Marcus Vinicius Guimarães de Lacerda
- Gerência de Malária, Fundação de Medicina Tropical Dr. Heitor Vieira Dourado, Manaus, Amazonas, Brazil.,Instituto Leônidas & Maria Deane, Fundação Oswaldo Cruz, Manaus, Amazonas, Brazil
| | - Vera Lucia Lanchote
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
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The activation of BAFF/APRIL system in spleen and lymph nodes of Plasmodium falciparum infected patients. Sci Rep 2020; 10:3865. [PMID: 32123265 PMCID: PMC7052189 DOI: 10.1038/s41598-020-60763-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 02/13/2020] [Indexed: 12/16/2022] Open
Abstract
Previous studies have reported activation of the B cell-activating factor (BAFF)/a proliferation-inducing ligand (APRIL) system in T independent immunity against malaria infection. Plasmodium falciparum (P. falciparum) infected animal model is not feasible. Therefore, little is known about the occurrence of BAFF/APRIL system and changes in falciparum lymphoid tissues. This study aimed to investigate the expression of BAFF/APRIL system components in lymphoid tissues from P. falciparum infected patients. Spleen and lymph node samples from 14 patients were collected at autopsy. Normal spleens and bacterially infected tonsils served as controls. The protein and/or mRNA expression of BAFF/APRIL and their cognate receptors, BAFF-R, TACI and BCMA, were determined by immunohistochemistry and RT-qPCR, respectively. The spleens of the patients exhibited significantly higher BAFF-R protein expression than normal spleens. Although without appropriate control, BCMA protein was markedly observed only in the lymph nodes. BAFF and BCMA mRNA levels were also significantly elevated in the spleen tissues of the patients compared with normal spleens. The overall BAFF-R protein levels in the lymphoid tissues of the patients correlated positively with parasitaemia. These findings are the first to confirm that BAFF/APRIL system activation in lymphoid tissues and is positively correlated with the parasitaemia levels in falciparum malaria.
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Antonelli LR, Junqueira C, Vinetz JM, Golenbock DT, Ferreira MU, Gazzinelli RT. The immunology of Plasmodium vivax malaria. Immunol Rev 2019; 293:163-189. [PMID: 31642531 DOI: 10.1111/imr.12816] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Accepted: 09/10/2019] [Indexed: 12/13/2022]
Abstract
Plasmodium vivax infection, the predominant cause of malaria in Asia and Latin America, affects ~14 million individuals annually, with considerable adverse effects on wellbeing and socioeconomic development. A clinical hallmark of Plasmodium infection, the paroxysm, is driven by pyrogenic cytokines produced during the immune response. Here, we review studies on the role of specific immune cell types, cognate innate immune receptors, and inflammatory cytokines on parasite control and disease symptoms. This review also summarizes studies on recurrent infections in individuals living in endemic regions as well as asymptomatic infections, a serious barrier to eliminating this disease. We propose potential mechanisms behind these repeated and subclinical infections, such as poor induction of immunological memory cells and inefficient T effector cells. We address the role of antibody-mediated resistance to P. vivax infection and discuss current progress in vaccine development. Finally, we review immunoregulatory mechanisms, such as inhibitory receptors, T regulatory cells, and the anti-inflammatory cytokine, IL-10, that antagonizes both innate and acquired immune responses, interfering with the development of protective immunity and parasite clearance. These studies provide new insights for the clinical management of symptomatic as well as asymptomatic individuals and the development of an efficacious vaccine for vivax malaria.
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Affiliation(s)
- Lis R Antonelli
- Instituto de Pesquisas Rene Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Brazil
| | - Caroline Junqueira
- Instituto de Pesquisas Rene Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Brazil
| | - Joseph M Vinetz
- Section of Infectious Diseases, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
| | - Douglas T Golenbock
- Division of Infectious Disease and immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Marcelo U Ferreira
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Ricardo T Gazzinelli
- Instituto de Pesquisas Rene Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Brazil.,Division of Infectious Disease and immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA.,Plataforma de Medicina Translacional, Fundação Oswaldo Cruz, Ribeirão Preto, Brazil
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The role of the BAFF/APRIL system in the T cell-independent specific response to blood stage Plasmodium falciparum hemozoin. Cytokine 2018; 111:445-453. [PMID: 29884307 DOI: 10.1016/j.cyto.2018.05.037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 05/28/2018] [Accepted: 05/29/2018] [Indexed: 01/18/2023]
Abstract
BACKGROUND The B cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL) are tumor necrosis factor family members that regulate B cell maturation, proliferation, survival and function. We have previously shown that blood-stage Plasmodium falciparum hemozoin (HZ) can act as a T-independent antigen (TI Ag) that induces the production of specific IgG to soluble crude P. falciparum Ag through the BAFF pathway. However, we have not yet clarified whether HZ need APRIL signaling in the TI response. Here, we aimed to clarify whether both BAFF and APRIL signaling pathways play roles in HZ induction of specific antibody production without T-cell help. METHODS Normal monocytes alone or co-cultured with naïve B cells were stimulated by HZ (10 µM) in vitro. Naïve B cell cultures, with HZ alone or with exogenous recombinant BAFF (rBAFF) and recombinant APRIL (rAPRIL) plus recombinant IL-4 (rIL-4) for 6 and 10 days were used as controls to investigate activation of B cells. At various times, the levels of sBAFF, sAPRIL, and HZ-specific IgG in the culture supernatants were assessed by enzyme-linked immunosorbent assay. The BAFF and APRIL expression levels on the HZ-stimulated monocytes and their specific receptors on activated B cells, including the BAFF receptor (BAFF-R), the transmembrane activator and calcium-modulator and cyclophilin ligand interactor (TACI) and the B cell maturation antigen (BCMA), were determined by flow cytometry. mRNA expression levels for the receptors were validated using Real-Time quantitative PCR. RESULTS HZ-activated monocytes released sBAFF and sAPRIL during the 72 h stimulation period. Increased mRNA encoding of their cognate receptors, BAFF-R, TACI, and BCMA, and increased HZ-specific IgG levels were also observed in HZ induction within the monocyte and B cell co-culture. The experiments under control conditions revealed that HZ alone could induce B cell culture to produce a small amount of the specific IgG compared with those in medium alone or rBAFF + rAPRIL + rIL-4. CONCLUSION Taken together, we suggest that in the TI response HZ stimulates monocyte and B cell co-culture to produce specific IgG through BAFF, APRIL and other independent complimentary signaling pathways.
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