Multiple sclerosis and related disorders, Jan 2, 2018
Multiple sclerosis (MS) afflicts more than 2.5 million individuals worldwide and this number is i... more Multiple sclerosis (MS) afflicts more than 2.5 million individuals worldwide and this number is increasing over time. Within the past years, a great number of disease-modifying treatments have emerged; however, efficacious treatments and a cure for MS await discovery. Thymosins, soluble hormone-like peptides produced by the thymus gland, can mediate immune and non-immune physiological processes and have gained interest in recent years as therapeutics in inflammatory and autoimmune diseases. Pubmed was searched with no time constraints for articles using a combination of the keywords "thymosin/s" or "thymus factor/s" AND "multiple sclerosis", mesh terms with no language restriction. Here, we review the state-of-the-art on the effects of thymosins on MS and its experimental models. In particular, we describe what is known in this field on the roles of thymosin-α1 (Tα1) and -β4 (Tβ4) as potential anti-inflammatory as well as neuroprotective and remyelinati...
B cells are key pathogenic effectors in multiple sclerosis (MS) and several therapies have been d... more B cells are key pathogenic effectors in multiple sclerosis (MS) and several therapies have been designed to restrain B cell abnormalities by directly targeting this lymphocyte population. Moving from our data showing a Toll-like receptor (TLR)7-driven dysregulation of B cell response in relapsing-remitting multiple sclerosis (RRMS) and having found a low serum level of Thymosin-α1 (Tα1) in patients, we investigated whether the addition of this molecule to peripheral blood mononuclear cells (PBMCs) would influence the expansion of regulatory B cell subsets, known to dampen autoimmune inflammation. Serum Tα1 level was measured by enzyme immunoassay. Cytokine expression was evaluated by Cytometric Bead Array (CBA), enzyme-linked immunosorbent assay (ELISA), and real-time reverse transcription polymerase chain reaction (RT-PCR). B cell subsets were analyzed by flow cytometry. Tα1 pre-treatment induces an anti-inflammatory status in TLR7-stimulated RRMS PBMC cultures, reducing the secret...
Controversial results have been obtained in studies of the effect of Mycobacterium tuberculosis o... more Controversial results have been obtained in studies of the effect of Mycobacterium tuberculosis on human immunodeficiency virus type 1 (HIV-1) replication in cells of the macrophage lineage. In the present study, monocyte-derived macrophages (MDMs), previously incubated for 2 days with heat-inactivated M. tuberculosis, were infected with HIV-1. M. tuberculosis consistently inhibited viral replication, and a similar result also was observed in the presence of supernatants from M. tuberculosis-stimulated MDMs, which indicates that this effect was mediated by soluble factors. Although CCR5-binding chemokines were induced by M. tuberculosis stimulation, the results of neutralization experiments indicated that it is unlikely that they were responsible for viral suppression. Inhibition occurred mainly after viral entry (demonstrated by use of a vesicular stomatitis virus G-pseudotyped HIV-1 and by analysis of HIV-1 early and late reverse-transcription products). Therefore, M. tuberculosis-induced factors may inhibit in vitro HIV-1 replication in macrophages by affecting an early postentry step in the HIV-1 cycle.
Growing evidences put B lymphocytes on a central stage in Multiple sclerosis (MS) immunopathology... more Growing evidences put B lymphocytes on a central stage in Multiple sclerosis (MS) immunopathology. While investigating the effects of Interferon (IFN)-β therapy, one of the most used first-line disease-modifying drugs for the treatment of Relapsing-Remitting MS (RRMS), in circulating B cell subpopulations we found a specific and dramatic decrease of CD27(+) memory B cells. Interestingly, memory B cells are considered a population with a great disease-driving relevance in MS and resulted to be also target of B cell depleting therapies. In addition, Epstein-barr virus (EBV), associated to MS etiopathogenesis, harbors in this cell type and an IFN-β-induced reduction of the memory B cell compartment, in turn, resulted in a decreased expression of the EBV gene Latent membrane protein 2A in treated patients. We found that in vivo IFN-β therapy specifically and highly induced apoptosis in memory B cells, in accordance with a strong increase of the apoptotic markers Annexin-V and active Cas...
Abstract: The transcription factor STAT-4 plays a pivotal role in the IL-12-mediated development ... more Abstract: The transcription factor STAT-4 plays a pivotal role in the IL-12-mediated development of naive CD4 T cells into the Th1 phenotype. Initially thought to be restricted to the lymphoid lineage, STAT-4 was subsequently shown to be ex- pressed in the myeloid compartment, mainly in activated monocytes, macrophages, and dendritic cells (DC). Here, we have studied STAT-4 in hu- man
Modern strategies to develop vaccines against Mycobacterium tuberculosis (Mtb) aim to improve the... more Modern strategies to develop vaccines against Mycobacterium tuberculosis (Mtb) aim to improve the current Bacillus Calmette-Guerin (BCG) vaccine or to attenuate the virulence of Mtb vaccine candidates. In the present study, the impact of wild type or mutated region of difference 1 (RD1) variants on the immunogenicity of Mtb and BCG recombinants was investigated in human primary dendritic cells (DC). A comparative analysis of transcriptome, signalling pathway activation, maturation, apoptosis, cytokine production and capacity to promote Th1 responses demonstrated that DC sense quantitative and qualitative differences in the expression of RD1-encoded factors-ESAT6 and CFP10-within BCG or Mtb backgrounds. Expansion of IFN-γ producing T cells was promoted by BCG::RD1-challenged DC, as compared to their BCG-infected counterparts. Although Mtb recombinants acted as a strong Th-1 promoting stimulus, even with RD1 deletion, the attenuated Mtb strain carrying a C-terminus truncated ESAT-6 elicited a robust Th1 promoting phenotype in DC. Collectively, these studies indicate a necessary but not sufficient role for the RD1 locus in promoting DC immune-regulatory functions. Additional mycobacterial factors are likely required to endow DC with a high Th1 polarizing capacity, a desirable attribute for a successful control of Mtb infection.
Journal of biological regulators and homeostatic agents
The effects of Candida albicans mannoproteins on the induction of a primary antibody response to ... more The effects of Candida albicans mannoproteins on the induction of a primary antibody response to a T-dependent antigen, sheep erythrocytes (SRBC), in cultures of human blood lymphocytes, were investigated. Two experimental systems (bulk and limiting dilution cultures) allowing the detection of both enhancing and inhibitory effects, were used. In bulk cultures, antigen alone elicited a small number of specific antibody forming cells, unless IL-2 was supplied. Addition of the fungal mannoprotein extract or of a purified constituent of it increased 5 to more than 10 times the specific response. When limiting dilution analysis was performed, we observed that: a) a similar number of specific precursor cells was induced by antigen and either IL-2 or mannoprotein; b) the plot of the number of seeded cells versus the log of the fraction of negative cultures was linear in antigen and IL-2 triggered cultures but constantly deviated from linearity when the candidal stimulant was added. Thus, more than one type of precursor cell was limiting in these cultures, and the immunoenhancing effect of mannoprotein may involve multiple cellular interactions.
The effect of a synthetic peptide, corresponding to a sequence of HIV-1 p24 protein (amino acids ... more The effect of a synthetic peptide, corresponding to a sequence of HIV-1 p24 protein (amino acids 218-237), on in vitro immune responses was studied. The peptide inhibited in a dose-dependent manner the induction of an anti-SRC antibody response and of a PPD-specific proliferative response of human PBL. On the other hand, PHA-induced proliferation of human PBL and PPD-induced proliferation of a PPD-specific human T-cell line were not modified by comparable amounts of the peptide. These results suggest that structures from a protein (p24), present in the serum throughout the course of HIV infection, are able to interfere with the inductive stages of specific immune responses. These findings may help to unravel some of the pathogenic mechanisms of AIDS and may contribute to the development of vaccine strategies.
Multiple sclerosis and related disorders, Jan 2, 2018
Multiple sclerosis (MS) afflicts more than 2.5 million individuals worldwide and this number is i... more Multiple sclerosis (MS) afflicts more than 2.5 million individuals worldwide and this number is increasing over time. Within the past years, a great number of disease-modifying treatments have emerged; however, efficacious treatments and a cure for MS await discovery. Thymosins, soluble hormone-like peptides produced by the thymus gland, can mediate immune and non-immune physiological processes and have gained interest in recent years as therapeutics in inflammatory and autoimmune diseases. Pubmed was searched with no time constraints for articles using a combination of the keywords "thymosin/s" or "thymus factor/s" AND "multiple sclerosis", mesh terms with no language restriction. Here, we review the state-of-the-art on the effects of thymosins on MS and its experimental models. In particular, we describe what is known in this field on the roles of thymosin-α1 (Tα1) and -β4 (Tβ4) as potential anti-inflammatory as well as neuroprotective and remyelinati...
B cells are key pathogenic effectors in multiple sclerosis (MS) and several therapies have been d... more B cells are key pathogenic effectors in multiple sclerosis (MS) and several therapies have been designed to restrain B cell abnormalities by directly targeting this lymphocyte population. Moving from our data showing a Toll-like receptor (TLR)7-driven dysregulation of B cell response in relapsing-remitting multiple sclerosis (RRMS) and having found a low serum level of Thymosin-α1 (Tα1) in patients, we investigated whether the addition of this molecule to peripheral blood mononuclear cells (PBMCs) would influence the expansion of regulatory B cell subsets, known to dampen autoimmune inflammation. Serum Tα1 level was measured by enzyme immunoassay. Cytokine expression was evaluated by Cytometric Bead Array (CBA), enzyme-linked immunosorbent assay (ELISA), and real-time reverse transcription polymerase chain reaction (RT-PCR). B cell subsets were analyzed by flow cytometry. Tα1 pre-treatment induces an anti-inflammatory status in TLR7-stimulated RRMS PBMC cultures, reducing the secret...
Controversial results have been obtained in studies of the effect of Mycobacterium tuberculosis o... more Controversial results have been obtained in studies of the effect of Mycobacterium tuberculosis on human immunodeficiency virus type 1 (HIV-1) replication in cells of the macrophage lineage. In the present study, monocyte-derived macrophages (MDMs), previously incubated for 2 days with heat-inactivated M. tuberculosis, were infected with HIV-1. M. tuberculosis consistently inhibited viral replication, and a similar result also was observed in the presence of supernatants from M. tuberculosis-stimulated MDMs, which indicates that this effect was mediated by soluble factors. Although CCR5-binding chemokines were induced by M. tuberculosis stimulation, the results of neutralization experiments indicated that it is unlikely that they were responsible for viral suppression. Inhibition occurred mainly after viral entry (demonstrated by use of a vesicular stomatitis virus G-pseudotyped HIV-1 and by analysis of HIV-1 early and late reverse-transcription products). Therefore, M. tuberculosis-induced factors may inhibit in vitro HIV-1 replication in macrophages by affecting an early postentry step in the HIV-1 cycle.
Growing evidences put B lymphocytes on a central stage in Multiple sclerosis (MS) immunopathology... more Growing evidences put B lymphocytes on a central stage in Multiple sclerosis (MS) immunopathology. While investigating the effects of Interferon (IFN)-β therapy, one of the most used first-line disease-modifying drugs for the treatment of Relapsing-Remitting MS (RRMS), in circulating B cell subpopulations we found a specific and dramatic decrease of CD27(+) memory B cells. Interestingly, memory B cells are considered a population with a great disease-driving relevance in MS and resulted to be also target of B cell depleting therapies. In addition, Epstein-barr virus (EBV), associated to MS etiopathogenesis, harbors in this cell type and an IFN-β-induced reduction of the memory B cell compartment, in turn, resulted in a decreased expression of the EBV gene Latent membrane protein 2A in treated patients. We found that in vivo IFN-β therapy specifically and highly induced apoptosis in memory B cells, in accordance with a strong increase of the apoptotic markers Annexin-V and active Cas...
Abstract: The transcription factor STAT-4 plays a pivotal role in the IL-12-mediated development ... more Abstract: The transcription factor STAT-4 plays a pivotal role in the IL-12-mediated development of naive CD4 T cells into the Th1 phenotype. Initially thought to be restricted to the lymphoid lineage, STAT-4 was subsequently shown to be ex- pressed in the myeloid compartment, mainly in activated monocytes, macrophages, and dendritic cells (DC). Here, we have studied STAT-4 in hu- man
Modern strategies to develop vaccines against Mycobacterium tuberculosis (Mtb) aim to improve the... more Modern strategies to develop vaccines against Mycobacterium tuberculosis (Mtb) aim to improve the current Bacillus Calmette-Guerin (BCG) vaccine or to attenuate the virulence of Mtb vaccine candidates. In the present study, the impact of wild type or mutated region of difference 1 (RD1) variants on the immunogenicity of Mtb and BCG recombinants was investigated in human primary dendritic cells (DC). A comparative analysis of transcriptome, signalling pathway activation, maturation, apoptosis, cytokine production and capacity to promote Th1 responses demonstrated that DC sense quantitative and qualitative differences in the expression of RD1-encoded factors-ESAT6 and CFP10-within BCG or Mtb backgrounds. Expansion of IFN-γ producing T cells was promoted by BCG::RD1-challenged DC, as compared to their BCG-infected counterparts. Although Mtb recombinants acted as a strong Th-1 promoting stimulus, even with RD1 deletion, the attenuated Mtb strain carrying a C-terminus truncated ESAT-6 elicited a robust Th1 promoting phenotype in DC. Collectively, these studies indicate a necessary but not sufficient role for the RD1 locus in promoting DC immune-regulatory functions. Additional mycobacterial factors are likely required to endow DC with a high Th1 polarizing capacity, a desirable attribute for a successful control of Mtb infection.
Journal of biological regulators and homeostatic agents
The effects of Candida albicans mannoproteins on the induction of a primary antibody response to ... more The effects of Candida albicans mannoproteins on the induction of a primary antibody response to a T-dependent antigen, sheep erythrocytes (SRBC), in cultures of human blood lymphocytes, were investigated. Two experimental systems (bulk and limiting dilution cultures) allowing the detection of both enhancing and inhibitory effects, were used. In bulk cultures, antigen alone elicited a small number of specific antibody forming cells, unless IL-2 was supplied. Addition of the fungal mannoprotein extract or of a purified constituent of it increased 5 to more than 10 times the specific response. When limiting dilution analysis was performed, we observed that: a) a similar number of specific precursor cells was induced by antigen and either IL-2 or mannoprotein; b) the plot of the number of seeded cells versus the log of the fraction of negative cultures was linear in antigen and IL-2 triggered cultures but constantly deviated from linearity when the candidal stimulant was added. Thus, more than one type of precursor cell was limiting in these cultures, and the immunoenhancing effect of mannoprotein may involve multiple cellular interactions.
The effect of a synthetic peptide, corresponding to a sequence of HIV-1 p24 protein (amino acids ... more The effect of a synthetic peptide, corresponding to a sequence of HIV-1 p24 protein (amino acids 218-237), on in vitro immune responses was studied. The peptide inhibited in a dose-dependent manner the induction of an anti-SRC antibody response and of a PPD-specific proliferative response of human PBL. On the other hand, PHA-induced proliferation of human PBL and PPD-induced proliferation of a PPD-specific human T-cell line were not modified by comparable amounts of the peptide. These results suggest that structures from a protein (p24), present in the serum throughout the course of HIV infection, are able to interfere with the inductive stages of specific immune responses. These findings may help to unravel some of the pathogenic mechanisms of AIDS and may contribute to the development of vaccine strategies.
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Papers by Elena Giacomini