Oleg Targoni - Academia.edu (original) (raw)
Papers by Oleg Targoni
<b>Copyright information:</b>Taken from "Immunogenicity of unprocessed and photo... more <b>Copyright information:</b>Taken from "Immunogenicity of unprocessed and photooxidized bovine and human osteochondral grafts in collagen-sensitive mice"BMC Musculoskeletal Disorders 2006;7():32-32.Published online 17 Mar 2006PMCID:PMC1459156.Copyright © 2006 Kawalec-Carroll et al; licensee BioMed Central Ltd.
SummaryModern health care needs preventive vaccines and therapeutic treatments with stability aga... more SummaryModern health care needs preventive vaccines and therapeutic treatments with stability against pathogen mutations to cope with current and future viral infections. At the beginning of the COVID-19 pandemic, our analytic and predictive tool identified a set of eight short SARS-CoV-2 S-spike protein epitopes that had the potential to persistently avoid mutation. Here a combination of genetic, Systems Biology and protein structure analyses confirm the stability of our identified epitopes against viral mutations. Remarkably, this research spans the whole period of the pandemic, during which 93.9% of the eight peptides remained invariable in the globally predominant 43 circulating variants, including Omicron. Likewise, the selected epitopes are conserved in 97% of all 1,514 known SARS-CoV-2 lineages. Finally, experimental analyses performed with these short peptides showed their specific immunoreactivity. This work opens a new perspective on the design of next-generation vaccines ...
Journal of Experimental Medicine, 1997
Synthetic oligodeoxynucleotides (ODN) that contain unmethylated CpG motifs (CpG ODN) induce macro... more Synthetic oligodeoxynucleotides (ODN) that contain unmethylated CpG motifs (CpG ODN) induce macrophages to secrete IL-12, which induces interferon (IFN)-γ secretion by natural killer (NK) cells. Since these cytokines can induce T helper 1 (Th1) differentiation, we examined the effects of coadministered CpG ODN on the differentiation of Th responses to hen egg lysozyme (HEL). In both BALB/c (Th2-biased) and B10.D2 (Th1-biased) mice, immunization with HEL in incomplete Freund's adjuvant (IFA) resulted in Th2-dominated immune responses characterized by HEL-specific secretion of IL-5 but not IFN-γ. In contrast, immunization with IFA-HEL plus CpG ODN switched the immune response to a Th1-dominated cytokine pattern, with high levels of HEL-specific IFN-γ secretion and decreased HEL-specific IL-5 production. IFA-HEL plus CpG ODN also induced anti-HEL IgG2a (a Th1-associated isotype), which was not induced by IFA-HEL alone. Control non–CpG ODN did not induce IFN-γ or IgG2a, excepting le...
Direct measurements of the frequency and the cytokine signature of the neuroantigen-specific effe... more Direct measurements of the frequency and the cytokine signature of the neuroantigen-specific effector cells in experimental allergic encephalomyelitis (EAE) are a continuing challenge. This is true for lymphoid tissues, and more importantly, for the CNS itself. Using enzyme-linked immunospot analysis (ELISPOT) assays, we followed proteolipid protein (PLP) 139-151-specific T cells engaged by active immunization of SJL mice. The total numbers of PLP 139-151-specific CD4 cells were highest before disease onset. At this time, these cells resided in lymphoid and nonlymphoid tissues, but were not detected in the CNS. While the PLP 139-151specific cells reached high frequencies in the CNS during clinical EAE, in absolute numbers, less than 20% of them were present in the target organ, with the majority residing in the periphery throughout all stages of the disease. The numbers of PLP 139-151specific cells gradually declined in both compartments with time. While eventually this first wave of effector cells completely disappeared from the CNS, PLP 178-191-specific cells became engaged, being detected first in the CNS. These data suggest that throughout all stages of EAE, the effector cells in the CNS are recruited from a vast peripheral reservoir, and that the second wave of effector cells is engaged while the first wave undergoes exhaustion.
In humans, studies of autoreactive T cells that mediate multiple sclerosis have been largely conf... more In humans, studies of autoreactive T cells that mediate multiple sclerosis have been largely confined to testing peripheral blood lymphocytes. Little is known how such measurements reflect the disease-mediating autoreactive T cells in the CNS. This information is also not available for murine experimental allergic encephalomyelitis (EAE); the low number of T cells that can be obtained from the blood or the brain of mice prevented such comparisons. We used single-cell resolution IFN-␥ ELISPOT assays to measure the frequencies and functional avidities of myelin basic protein (MBP:87-99)-specific CD4 cells in SJL mice immunized with this peptide. Functional MBP:87-99-specific IFN-␥-producing cells were present in the CNS during clinical signs of EAE, but not during phases of recovery. In contrast, MBP:87-99-specific T cells persisted in the blood during all stages of the disease, and were also present in mice that did not develop EAE. Therefore, the increased frequency of MBP:87-99-reactive T cells in the blood reliably reflected the primed state, but not the inflammatory activity of these cells in the brain. The functional avidity of the MBP:87-99-reactive T cells was identical in the brain and blood and did not change over 2 mo as the mice progressed from acute to chronic EAE. Therefore, high-affinity T cells did not become selectively enriched in the target organ, and avidity maturation of the MBP:87-99-specific T cell repertoire did not occur in the observation period. The data may help the interpretation of measurements made with peripheral blood lymphocytes of multiple sclerosis patients.
The Journal of Infectious Diseases, 2001
To determine whether systemic immunization against Helicobacter pylori could be achieved with an ... more To determine whether systemic immunization against Helicobacter pylori could be achieved with an adjuvant approved for human use, the efficacy of vaccination with Helicobacter antigen in combination with aluminum hydroxide (AlOH) was evaluated in a murine model of Helicobacter infection. Immunization with antigen and AlOH induced interleukin-5secreting, antigen-specific T cells, and immunization with antigen and complete Freund's adjuvant induced interferon-g-secreting, antigen-specific T cells, as determined by ELISPOT assay. Both immune responses conferred protection after challenge with either H. pylori or H. felis, as confirmed by the complete absence of any bacteria, as assessed by both histology and culture of gastric biopsy samples. Protection was antibody independent, as demonstrated with antibody-deficient mMT mice (immunoglobulin-gene knockout mice), and CD4 + spleen T cells from immunized mice were sufficient to transfer protective immunity to otherwise immunodeficient rag1 Ϫ/Ϫ recipients. These results suggest an alternative and potentially more expeditious strategy for development of a human-use H. pylori vaccine. Helicobacter pylori, one of the world's most prevalent pathogens, is an extracellular bacterium that infects the gastric mucosa and plays an etiologic role in gastritis and peptic ulcer disease [1, 2]. It is generally believed that infection occurs primarily in young children. Therefore, a prophylactic vaccine administered to infants might prevent H. pylori infection and the long-term consequences that occur in adults. Vaccination strategies have focused primarily on orally and intranasally administered immunizations to induce mucosal immunity [3]. These immunizations require bacterial exotoxin adjuvants that are unsafe for use in humans. Systemic immunization has recently been reported as a possible means of inducing protective
Cellular Immunology, 2009
Immunization with vaccinia virus causes long-term immunity. Efforts have been made to characteriz... more Immunization with vaccinia virus causes long-term immunity. Efforts have been made to characterize the T cells responsible for this protection. Recently, T cell subsets were described that not only co-express multiple cytokines, but also show increased per cell cytokine productivity. These highly productive cells are often considered to be the most protective. We used ELISPOT assays to measure per cell IFN-gamma productivity of vaccinia-specific T cells in childhood immunized adults immediately before and at different time points after vaccinia re-vaccination. Apart from an increase in frequency, we found a marked increase of IFN-gamma productivity following vaccinia re-vaccination. However, these changes were short-lived as both parameters quickly returned to baseline values within 22days after re-vaccination. Therefore, increased per cell IFN-gamma productivity seems to be a sign of recent in vivo T cell activation rather than a stable marker of a distinct T cell subset responsible for long-term immune protection.
Bulletin of Experimental Biology and Medicine, 1994
It is shown that biologically active peptides inhibit the concanavalin A-induced generation of ce... more It is shown that biologically active peptides inhibit the concanavalin A-induced generation of cells which may proliferate in response to exogenous recombinant interleukin-2. Determination of the number of CD25-containing cells showed that synthetic peptides are able to lower not only the number of CD25-containing cells but the level of its expression as well.
Bulletin of Experimental Biology and Medicine, 1994
Human α-2 interferon and peptides representing parts of the amino-acid sequence 124–138 of the IF... more Human α-2 interferon and peptides representing parts of the amino-acid sequence 124–138 of the IF molecule inhibit the proliferative response of peripheral blood lymphocytes from healthy donorsin vitro induced by ConA. It is shown that neither interferon α-2 nor biologically active peptides change the level of interleukin-2 ConA-induced production by human blood mononuclears.
The Journal of Immunology, 2001
Direct measurements of the frequency and the cytokine signature of the neuroantigen-specific effe... more Direct measurements of the frequency and the cytokine signature of the neuroantigen-specific effector cells in experimental allergic encephalomyelitis (EAE) are a continuing challenge. This is true for lymphoid tissues, and more importantly, for the CNS itself. Using enzyme-linked immunospot analysis (ELISPOT) assays, we followed proteolipid protein (PLP) 139-151-specific T cells engaged by active immunization of SJL mice. The total numbers of PLP 139-151-specific CD4 cells were highest before disease onset. At this time, these cells resided in lymphoid and nonlymphoid tissues, but were not detected in the CNS. While the PLP 139-151specific cells reached high frequencies in the CNS during clinical EAE, in absolute numbers, less than 20% of them were present in the target organ, with the majority residing in the periphery throughout all stages of the disease. The numbers of PLP 139-151specific cells gradually declined in both compartments with time. While eventually this first wave of effector cells completely disappeared from the CNS, PLP 178-191-specific cells became engaged, being detected first in the CNS. These data suggest that throughout all stages of EAE, the effector cells in the CNS are recruited from a vast peripheral reservoir, and that the second wave of effector cells is engaged while the first wave undergoes exhaustion.
The Journal of …, 2005
In humans, studies of autoreactive T cells that mediate multiple sclerosis have been largely conf... more In humans, studies of autoreactive T cells that mediate multiple sclerosis have been largely confined to testing peripheral blood lymphocytes. Little is known how such measurements reflect the disease-mediating autoreactive T cells in the CNS. This information is also not ...
BMC musculoskeletal disorders, 2005
One means of treating osteoarthritis is with autologous or allogeneic osteochondral grafts. The p... more One means of treating osteoarthritis is with autologous or allogeneic osteochondral grafts. The purpose of this study was to evaluate the innate immunological response in humans toward xeno-derived osteochondral grafts that have been partially or entirely treated by the photooxidation process. The antigens tested included bovine, porcine, ovine and equine osteochondral samples that have been treated in successive steps of photooxidation. ELISPOT assays were used to evaluate the production of IL-1, IL-4, IL-6, IL-10, IL-12 and TNF-alpha by human monocytes in response to the antigens. Results indicated vigorous production of IL-1, IL-6, IL-10 and TNF-alpha in response to untreated bovine, porcine and equine specimens. This indicates that these samples are perceived as foreign, or stimulatory, by the human monocytes. There was no induction of IL-4 or IL-12, which is required for Th2 and Th1 immunity, respectively. In contrast, the processed bovine, porcine and equine samples did not in...
BMC musculoskeletal disorders, 2006
Autologous and allogeneic osteochondral grafts have been used to repair damaged or diseased carti... more Autologous and allogeneic osteochondral grafts have been used to repair damaged or diseased cartilage. There are drawbacks to both of these methods, however. Another possible source for osteochondral grafting is photooxidized xenograft scaffolds. The purpose of this study was to evaluate the adaptive immune response to unprocessed and photooxidized xenogeneic osteochondral grafts in a collagen-sensitive mouse model. Unprocessed and photooxidized bovine and human osteochondral grafts were used. The grafts were implanted subcutaneously in collagen-sensitive DBA/1LacJ mice for four or twelve weeks. ELISPOT assays were conducted with spleen cells to evaluate the number of collagen-specific T cells that produce IL-2, IL-4, IL-5 or IFN-gamma. Serum was collected and ELISA assays were performed to determine the titers of collagen-specific and total IgG, IgG1, IgG2a, or IgM antibodies. Histology was conducted on the retrieved osteochondral grafts. Results indicated that, with respect to ada...
Journal for ImmunoTherapy of Cancer, 2013
Journal for ImmunoTherapy of Cancer, 2013
Journal for ImmunoTherapy of Cancer, 2013
Viruses, 2012
Immune monitoring of T cell responses increasingly relies on the use of peptide pools. Peptides, ... more Immune monitoring of T cell responses increasingly relies on the use of peptide pools. Peptides, when restricted by the same HLA allele, and presented from within the same peptide pool, can compete for HLA binding sites. What impact such competition has on functional T cell stimulation, however, is not clear. Using a model peptide pool that is comprised of 32 well-defined viral epitopes from Cytomegalovirus, Epstein-Barr virus, and Influenza viruses (CEF peptide pool), we assessed peptide competition in PBMC from 42 human subjects. The magnitude of the peptide pool-elicited CD8 T cell responses was a mean 79% and a median 77% of the sum of the CD8 T cell responses elicited by the individual peptides. Therefore, while the effect of peptide competition was evident, it was of a relatively minor magnitude. By studying the dose-response curves for individual CEF peptides, we show that several of these peptides are present in the CEF-pool at concentrations that are orders of magnitude in excess of what is needed for the activation threshold of the CD8 T cells. The presence of such T cells with very high functional avidity for the viral antigens can explain why the effect of peptide competition is relatively minor within the CEF-pool.
Cells, 2015
Each positive well in ELISPOT assays contains spots of variable sizes that can range from tens of... more Each positive well in ELISPOT assays contains spots of variable sizes that can range from tens of micrometers up to a millimeter in diameter. Therefore, when it comes to counting these spots the decision on setting the lower and the upper spot size thresholds to discriminate between non-specific background noise, spots produced by individual T cells, and spots formed by T cell clusters is critical. If the spot sizes follow a known statistical distribution, precise predictions on minimal and maximal spot sizes, belonging to a given T cell population, can be made. We studied the size distributional properties of IFN-γ, IL-2, IL-4, IL-5 and IL-17 spots elicited in ELISPOT assays with PBMC from 172 healthy donors, upon stimulation with 32 individual viral peptides representing defined HLA Class I-restricted epitopes for CD8 cells, and with protein antigens of CMV and EBV activating CD4 cells. A total of 334 CD8 and 80 CD4 positive T cell responses were analyzed. In 99.7% of the test cas...
<b>Copyright information:</b>Taken from "Immunogenicity of unprocessed and photo... more <b>Copyright information:</b>Taken from "Immunogenicity of unprocessed and photooxidized bovine and human osteochondral grafts in collagen-sensitive mice"BMC Musculoskeletal Disorders 2006;7():32-32.Published online 17 Mar 2006PMCID:PMC1459156.Copyright © 2006 Kawalec-Carroll et al; licensee BioMed Central Ltd.
SummaryModern health care needs preventive vaccines and therapeutic treatments with stability aga... more SummaryModern health care needs preventive vaccines and therapeutic treatments with stability against pathogen mutations to cope with current and future viral infections. At the beginning of the COVID-19 pandemic, our analytic and predictive tool identified a set of eight short SARS-CoV-2 S-spike protein epitopes that had the potential to persistently avoid mutation. Here a combination of genetic, Systems Biology and protein structure analyses confirm the stability of our identified epitopes against viral mutations. Remarkably, this research spans the whole period of the pandemic, during which 93.9% of the eight peptides remained invariable in the globally predominant 43 circulating variants, including Omicron. Likewise, the selected epitopes are conserved in 97% of all 1,514 known SARS-CoV-2 lineages. Finally, experimental analyses performed with these short peptides showed their specific immunoreactivity. This work opens a new perspective on the design of next-generation vaccines ...
Journal of Experimental Medicine, 1997
Synthetic oligodeoxynucleotides (ODN) that contain unmethylated CpG motifs (CpG ODN) induce macro... more Synthetic oligodeoxynucleotides (ODN) that contain unmethylated CpG motifs (CpG ODN) induce macrophages to secrete IL-12, which induces interferon (IFN)-γ secretion by natural killer (NK) cells. Since these cytokines can induce T helper 1 (Th1) differentiation, we examined the effects of coadministered CpG ODN on the differentiation of Th responses to hen egg lysozyme (HEL). In both BALB/c (Th2-biased) and B10.D2 (Th1-biased) mice, immunization with HEL in incomplete Freund's adjuvant (IFA) resulted in Th2-dominated immune responses characterized by HEL-specific secretion of IL-5 but not IFN-γ. In contrast, immunization with IFA-HEL plus CpG ODN switched the immune response to a Th1-dominated cytokine pattern, with high levels of HEL-specific IFN-γ secretion and decreased HEL-specific IL-5 production. IFA-HEL plus CpG ODN also induced anti-HEL IgG2a (a Th1-associated isotype), which was not induced by IFA-HEL alone. Control non–CpG ODN did not induce IFN-γ or IgG2a, excepting le...
Direct measurements of the frequency and the cytokine signature of the neuroantigen-specific effe... more Direct measurements of the frequency and the cytokine signature of the neuroantigen-specific effector cells in experimental allergic encephalomyelitis (EAE) are a continuing challenge. This is true for lymphoid tissues, and more importantly, for the CNS itself. Using enzyme-linked immunospot analysis (ELISPOT) assays, we followed proteolipid protein (PLP) 139-151-specific T cells engaged by active immunization of SJL mice. The total numbers of PLP 139-151-specific CD4 cells were highest before disease onset. At this time, these cells resided in lymphoid and nonlymphoid tissues, but were not detected in the CNS. While the PLP 139-151specific cells reached high frequencies in the CNS during clinical EAE, in absolute numbers, less than 20% of them were present in the target organ, with the majority residing in the periphery throughout all stages of the disease. The numbers of PLP 139-151specific cells gradually declined in both compartments with time. While eventually this first wave of effector cells completely disappeared from the CNS, PLP 178-191-specific cells became engaged, being detected first in the CNS. These data suggest that throughout all stages of EAE, the effector cells in the CNS are recruited from a vast peripheral reservoir, and that the second wave of effector cells is engaged while the first wave undergoes exhaustion.
In humans, studies of autoreactive T cells that mediate multiple sclerosis have been largely conf... more In humans, studies of autoreactive T cells that mediate multiple sclerosis have been largely confined to testing peripheral blood lymphocytes. Little is known how such measurements reflect the disease-mediating autoreactive T cells in the CNS. This information is also not available for murine experimental allergic encephalomyelitis (EAE); the low number of T cells that can be obtained from the blood or the brain of mice prevented such comparisons. We used single-cell resolution IFN-␥ ELISPOT assays to measure the frequencies and functional avidities of myelin basic protein (MBP:87-99)-specific CD4 cells in SJL mice immunized with this peptide. Functional MBP:87-99-specific IFN-␥-producing cells were present in the CNS during clinical signs of EAE, but not during phases of recovery. In contrast, MBP:87-99-specific T cells persisted in the blood during all stages of the disease, and were also present in mice that did not develop EAE. Therefore, the increased frequency of MBP:87-99-reactive T cells in the blood reliably reflected the primed state, but not the inflammatory activity of these cells in the brain. The functional avidity of the MBP:87-99-reactive T cells was identical in the brain and blood and did not change over 2 mo as the mice progressed from acute to chronic EAE. Therefore, high-affinity T cells did not become selectively enriched in the target organ, and avidity maturation of the MBP:87-99-specific T cell repertoire did not occur in the observation period. The data may help the interpretation of measurements made with peripheral blood lymphocytes of multiple sclerosis patients.
The Journal of Infectious Diseases, 2001
To determine whether systemic immunization against Helicobacter pylori could be achieved with an ... more To determine whether systemic immunization against Helicobacter pylori could be achieved with an adjuvant approved for human use, the efficacy of vaccination with Helicobacter antigen in combination with aluminum hydroxide (AlOH) was evaluated in a murine model of Helicobacter infection. Immunization with antigen and AlOH induced interleukin-5secreting, antigen-specific T cells, and immunization with antigen and complete Freund's adjuvant induced interferon-g-secreting, antigen-specific T cells, as determined by ELISPOT assay. Both immune responses conferred protection after challenge with either H. pylori or H. felis, as confirmed by the complete absence of any bacteria, as assessed by both histology and culture of gastric biopsy samples. Protection was antibody independent, as demonstrated with antibody-deficient mMT mice (immunoglobulin-gene knockout mice), and CD4 + spleen T cells from immunized mice were sufficient to transfer protective immunity to otherwise immunodeficient rag1 Ϫ/Ϫ recipients. These results suggest an alternative and potentially more expeditious strategy for development of a human-use H. pylori vaccine. Helicobacter pylori, one of the world's most prevalent pathogens, is an extracellular bacterium that infects the gastric mucosa and plays an etiologic role in gastritis and peptic ulcer disease [1, 2]. It is generally believed that infection occurs primarily in young children. Therefore, a prophylactic vaccine administered to infants might prevent H. pylori infection and the long-term consequences that occur in adults. Vaccination strategies have focused primarily on orally and intranasally administered immunizations to induce mucosal immunity [3]. These immunizations require bacterial exotoxin adjuvants that are unsafe for use in humans. Systemic immunization has recently been reported as a possible means of inducing protective
Cellular Immunology, 2009
Immunization with vaccinia virus causes long-term immunity. Efforts have been made to characteriz... more Immunization with vaccinia virus causes long-term immunity. Efforts have been made to characterize the T cells responsible for this protection. Recently, T cell subsets were described that not only co-express multiple cytokines, but also show increased per cell cytokine productivity. These highly productive cells are often considered to be the most protective. We used ELISPOT assays to measure per cell IFN-gamma productivity of vaccinia-specific T cells in childhood immunized adults immediately before and at different time points after vaccinia re-vaccination. Apart from an increase in frequency, we found a marked increase of IFN-gamma productivity following vaccinia re-vaccination. However, these changes were short-lived as both parameters quickly returned to baseline values within 22days after re-vaccination. Therefore, increased per cell IFN-gamma productivity seems to be a sign of recent in vivo T cell activation rather than a stable marker of a distinct T cell subset responsible for long-term immune protection.
Bulletin of Experimental Biology and Medicine, 1994
It is shown that biologically active peptides inhibit the concanavalin A-induced generation of ce... more It is shown that biologically active peptides inhibit the concanavalin A-induced generation of cells which may proliferate in response to exogenous recombinant interleukin-2. Determination of the number of CD25-containing cells showed that synthetic peptides are able to lower not only the number of CD25-containing cells but the level of its expression as well.
Bulletin of Experimental Biology and Medicine, 1994
Human α-2 interferon and peptides representing parts of the amino-acid sequence 124–138 of the IF... more Human α-2 interferon and peptides representing parts of the amino-acid sequence 124–138 of the IF molecule inhibit the proliferative response of peripheral blood lymphocytes from healthy donorsin vitro induced by ConA. It is shown that neither interferon α-2 nor biologically active peptides change the level of interleukin-2 ConA-induced production by human blood mononuclears.
The Journal of Immunology, 2001
Direct measurements of the frequency and the cytokine signature of the neuroantigen-specific effe... more Direct measurements of the frequency and the cytokine signature of the neuroantigen-specific effector cells in experimental allergic encephalomyelitis (EAE) are a continuing challenge. This is true for lymphoid tissues, and more importantly, for the CNS itself. Using enzyme-linked immunospot analysis (ELISPOT) assays, we followed proteolipid protein (PLP) 139-151-specific T cells engaged by active immunization of SJL mice. The total numbers of PLP 139-151-specific CD4 cells were highest before disease onset. At this time, these cells resided in lymphoid and nonlymphoid tissues, but were not detected in the CNS. While the PLP 139-151specific cells reached high frequencies in the CNS during clinical EAE, in absolute numbers, less than 20% of them were present in the target organ, with the majority residing in the periphery throughout all stages of the disease. The numbers of PLP 139-151specific cells gradually declined in both compartments with time. While eventually this first wave of effector cells completely disappeared from the CNS, PLP 178-191-specific cells became engaged, being detected first in the CNS. These data suggest that throughout all stages of EAE, the effector cells in the CNS are recruited from a vast peripheral reservoir, and that the second wave of effector cells is engaged while the first wave undergoes exhaustion.
The Journal of …, 2005
In humans, studies of autoreactive T cells that mediate multiple sclerosis have been largely conf... more In humans, studies of autoreactive T cells that mediate multiple sclerosis have been largely confined to testing peripheral blood lymphocytes. Little is known how such measurements reflect the disease-mediating autoreactive T cells in the CNS. This information is also not ...
BMC musculoskeletal disorders, 2005
One means of treating osteoarthritis is with autologous or allogeneic osteochondral grafts. The p... more One means of treating osteoarthritis is with autologous or allogeneic osteochondral grafts. The purpose of this study was to evaluate the innate immunological response in humans toward xeno-derived osteochondral grafts that have been partially or entirely treated by the photooxidation process. The antigens tested included bovine, porcine, ovine and equine osteochondral samples that have been treated in successive steps of photooxidation. ELISPOT assays were used to evaluate the production of IL-1, IL-4, IL-6, IL-10, IL-12 and TNF-alpha by human monocytes in response to the antigens. Results indicated vigorous production of IL-1, IL-6, IL-10 and TNF-alpha in response to untreated bovine, porcine and equine specimens. This indicates that these samples are perceived as foreign, or stimulatory, by the human monocytes. There was no induction of IL-4 or IL-12, which is required for Th2 and Th1 immunity, respectively. In contrast, the processed bovine, porcine and equine samples did not in...
BMC musculoskeletal disorders, 2006
Autologous and allogeneic osteochondral grafts have been used to repair damaged or diseased carti... more Autologous and allogeneic osteochondral grafts have been used to repair damaged or diseased cartilage. There are drawbacks to both of these methods, however. Another possible source for osteochondral grafting is photooxidized xenograft scaffolds. The purpose of this study was to evaluate the adaptive immune response to unprocessed and photooxidized xenogeneic osteochondral grafts in a collagen-sensitive mouse model. Unprocessed and photooxidized bovine and human osteochondral grafts were used. The grafts were implanted subcutaneously in collagen-sensitive DBA/1LacJ mice for four or twelve weeks. ELISPOT assays were conducted with spleen cells to evaluate the number of collagen-specific T cells that produce IL-2, IL-4, IL-5 or IFN-gamma. Serum was collected and ELISA assays were performed to determine the titers of collagen-specific and total IgG, IgG1, IgG2a, or IgM antibodies. Histology was conducted on the retrieved osteochondral grafts. Results indicated that, with respect to ada...
Journal for ImmunoTherapy of Cancer, 2013
Journal for ImmunoTherapy of Cancer, 2013
Journal for ImmunoTherapy of Cancer, 2013
Viruses, 2012
Immune monitoring of T cell responses increasingly relies on the use of peptide pools. Peptides, ... more Immune monitoring of T cell responses increasingly relies on the use of peptide pools. Peptides, when restricted by the same HLA allele, and presented from within the same peptide pool, can compete for HLA binding sites. What impact such competition has on functional T cell stimulation, however, is not clear. Using a model peptide pool that is comprised of 32 well-defined viral epitopes from Cytomegalovirus, Epstein-Barr virus, and Influenza viruses (CEF peptide pool), we assessed peptide competition in PBMC from 42 human subjects. The magnitude of the peptide pool-elicited CD8 T cell responses was a mean 79% and a median 77% of the sum of the CD8 T cell responses elicited by the individual peptides. Therefore, while the effect of peptide competition was evident, it was of a relatively minor magnitude. By studying the dose-response curves for individual CEF peptides, we show that several of these peptides are present in the CEF-pool at concentrations that are orders of magnitude in excess of what is needed for the activation threshold of the CD8 T cells. The presence of such T cells with very high functional avidity for the viral antigens can explain why the effect of peptide competition is relatively minor within the CEF-pool.
Cells, 2015
Each positive well in ELISPOT assays contains spots of variable sizes that can range from tens of... more Each positive well in ELISPOT assays contains spots of variable sizes that can range from tens of micrometers up to a millimeter in diameter. Therefore, when it comes to counting these spots the decision on setting the lower and the upper spot size thresholds to discriminate between non-specific background noise, spots produced by individual T cells, and spots formed by T cell clusters is critical. If the spot sizes follow a known statistical distribution, precise predictions on minimal and maximal spot sizes, belonging to a given T cell population, can be made. We studied the size distributional properties of IFN-γ, IL-2, IL-4, IL-5 and IL-17 spots elicited in ELISPOT assays with PBMC from 172 healthy donors, upon stimulation with 32 individual viral peptides representing defined HLA Class I-restricted epitopes for CD8 cells, and with protein antigens of CMV and EBV activating CD4 cells. A total of 334 CD8 and 80 CD4 positive T cell responses were analyzed. In 99.7% of the test cas...