Nutrition during perinatal period is more critical for the developme nt of the immune system than during adulthood, and the relationship between earl y nutrition and diseases in later life has been established. In hum...Nutrition during perinatal period is more critical for the developme nt of the immune system than during adulthood, and the relationship between earl y nutrition and diseases in later life has been established. In humans and labor atory animals, the plasticity of metabolic function in foetuses or neonates enab les them to adapt to malnutrition for survival; however, such an adaptation, as usually evidenced by retarded growth, stunted development of lymphoid organs and impaired immunocompetence, can maintain and persist into later life even when n utrition is improved. Early nutrition may thus programme' the immune system of a nimals. Limited experimental studies have also revealed that long-term immunity against nematode parasites in sheep can be enhanced by a short-term protein su pplementation shortly after weaning, a form of 'nutritional programming', but su ch an effect appears to vanish if the nutritional status of young animals alread y meets at least the requirement for maintenance.展开更多
Evidence from epidemiological studies indicates an inverse correlation between the incidence of certain immune-mediated diseases, including inflammatory bowel diseases (IBD), and exposure to helminths. Helminth parasi...Evidence from epidemiological studies indicates an inverse correlation between the incidence of certain immune-mediated diseases, including inflammatory bowel diseases (IBD), and exposure to helminths. Helminth parasites are the classic inducers of Th2 responses. The Th2-polarized T cell response driven by helminth infection has been linked to the attenuation of some damaging Th1 driven inflammatory responses, preventing some Th1-mediated autoimmune diseases in the host, including experimentally induced colitis. Helminth parasites (the porcine whipworm, Trichuris suis ) have been tested for treating IBD patients, resulting in clinical amelioration of the disease. As a result, there is a great deal of interest in the research community in exploring the therapeutic use of helminth parasites for the control of immune-mediated diseases, including IBD. However, recent studies have provided evidence indicating the exacerbating effects of helminths on bacterial as well as non-infectious colitis in animal models. Therefore, a better understanding of mechanisms by which helminths modulate host immune responses in the gut may reveal novel, more effective and safer approaches to helminth-based therapy of IBD.展开更多
Toll-like receptors(TLRs) are a central component of innate immune system and play a major role as the initiator of the innate immune responses to defend against bacteria,viruses,parasite and other pathogens.During ma...Toll-like receptors(TLRs) are a central component of innate immune system and play a major role as the initiator of the innate immune responses to defend against bacteria,viruses,parasite and other pathogens.During malaria infection,TLRs signaling pathways are initialed with the recognition of Plasmodium glycosylphosphatidylinositols(GPI) and hemozoin as pathogen-associated molecular patterns(PAMPs).And then,activation of TLRs signaling induces specific biological responses against malaria parasites invasion.However,TLRs are also involved in malaria pathogenesis and enhancement of immune tolerance and evasion for malaria infection.Moreover,malaria parasites regulate selectively TLRs expression on immune cells.Thus,these evidences indicated that TLRs have contrary roles on malaria infection.Understanding the complicated roles of TLRs on malaria infection will contribute us to design more effective anti-malaria drugs or vaccines.展开更多
We have previously demonstrated the ability of malaria parasites to interfere with specific immune responses. CD4 T cells specific to parasite antigens, but not CD4 T cells specific to an irrelevant antigen, ovalbumin...We have previously demonstrated the ability of malaria parasites to interfere with specific immune responses. CD4 T cells specific to parasite antigens, but not CD4 T cells specific to an irrelevant antigen, ovalbumin (OVA), are de- leted via apoptosis during malaria infection. It is of interest, therefore, to investigate the immune responses that developed following vaccination with the 19 kDa carboxylterminus of the merozoite surface protein 1 (MSP119) in mice that had previ- ously experienced malaria infection. In this study, pre-exposure of mice to Plasmodium yoelii elicited native anti-MSP119 an- tibody responses, which could be boosted by vaccination with recombinant MSP119 . likewise, infection of MSP119-primed mice with Plasmodium yoelii ( P . yoelii) led to an increase of anti-MSP119 antibodies. MSP119 vaccination of malaria pre- exposed mice or immunization by infection/cure of MSP119-primed mice enabled the mice to survive challenge infection, with the former group having slightly lower parasitaemia. The data suggest that exposure to malaria infection primes a natural im- mune response which can be boosted by vaccination. This information is relevant to the development of a vaccine for use in individuals living in malaria-endemic areas.展开更多
Both eukaryotic and prokaryotic pathogens infect the host stably via an immune evasion mecha- nism termed mutually exclusive expression. Nowadays, little is known about this epigenetic mechanism, largely limiting th...Both eukaryotic and prokaryotic pathogens infect the host stably via an immune evasion mecha- nism termed mutually exclusive expression. Nowadays, little is known about this epigenetic mechanism, largely limiting the understanding of pathogenesis of many bacterial, fungal and protozoan pathogens and therefore the development of novel drugs and vaccines. In the most severe malaria parasite, Plasrnodiurn falciparum, there is a major virulence gene family termed vat, by which the variant antigen PfEMP1 is encoded and expressed on the surface of parasite-infected erythrocytes. Each parasite carries about 60 anti- genically various vat genes, however, only one of which is expressed at a given time during infection. P. falciparum expresses PfEMP1s in this clonally variant manner to bind to different human endothelial re- ceptors, allowing the infected erythrocytes to sequester in tissues to escape the host＇s immune response in- cluding spleen killing and humoral immunity. At present, the mechanism of mutually exclusive expression of the var gene family remains largely unknown, even though there is increasing evidence suggesting im- portant roles of the epigenetic regulation involved in vat gene expression. In addition, epigenetic factors were also found in association with transcriptional regulation of other antigenic variant gene families in P. falciparum. In this paper, we review the current understanding of epigenetic regulations of P. falcipa- rum virulence genes with particular views toward the design of novel vaccines, drugs, and diagnosis to ma- laria.展开更多
文摘Nutrition during perinatal period is more critical for the developme nt of the immune system than during adulthood, and the relationship between earl y nutrition and diseases in later life has been established. In humans and labor atory animals, the plasticity of metabolic function in foetuses or neonates enab les them to adapt to malnutrition for survival; however, such an adaptation, as usually evidenced by retarded growth, stunted development of lymphoid organs and impaired immunocompetence, can maintain and persist into later life even when n utrition is improved. Early nutrition may thus programme' the immune system of a nimals. Limited experimental studies have also revealed that long-term immunity against nematode parasites in sheep can be enhanced by a short-term protein su pplementation shortly after weaning, a form of 'nutritional programming', but su ch an effect appears to vanish if the nutritional status of young animals alread y meets at least the requirement for maintenance.
基金Grant DK 074727 (R21) from the National Institutes of HealthAn unrestricted educational grant from Wyeth NutritionA research fellowship from the Research Center for High Altitude Medicine, Qinghai University Medical School, China
文摘Evidence from epidemiological studies indicates an inverse correlation between the incidence of certain immune-mediated diseases, including inflammatory bowel diseases (IBD), and exposure to helminths. Helminth parasites are the classic inducers of Th2 responses. The Th2-polarized T cell response driven by helminth infection has been linked to the attenuation of some damaging Th1 driven inflammatory responses, preventing some Th1-mediated autoimmune diseases in the host, including experimentally induced colitis. Helminth parasites (the porcine whipworm, Trichuris suis ) have been tested for treating IBD patients, resulting in clinical amelioration of the disease. As a result, there is a great deal of interest in the research community in exploring the therapeutic use of helminth parasites for the control of immune-mediated diseases, including IBD. However, recent studies have provided evidence indicating the exacerbating effects of helminths on bacterial as well as non-infectious colitis in animal models. Therefore, a better understanding of mechanisms by which helminths modulate host immune responses in the gut may reveal novel, more effective and safer approaches to helminth-based therapy of IBD.
文摘Toll-like receptors(TLRs) are a central component of innate immune system and play a major role as the initiator of the innate immune responses to defend against bacteria,viruses,parasite and other pathogens.During malaria infection,TLRs signaling pathways are initialed with the recognition of Plasmodium glycosylphosphatidylinositols(GPI) and hemozoin as pathogen-associated molecular patterns(PAMPs).And then,activation of TLRs signaling induces specific biological responses against malaria parasites invasion.However,TLRs are also involved in malaria pathogenesis and enhancement of immune tolerance and evasion for malaria infection.Moreover,malaria parasites regulate selectively TLRs expression on immune cells.Thus,these evidences indicated that TLRs have contrary roles on malaria infection.Understanding the complicated roles of TLRs on malaria infection will contribute us to design more effective anti-malaria drugs or vaccines.
文摘We have previously demonstrated the ability of malaria parasites to interfere with specific immune responses. CD4 T cells specific to parasite antigens, but not CD4 T cells specific to an irrelevant antigen, ovalbumin (OVA), are de- leted via apoptosis during malaria infection. It is of interest, therefore, to investigate the immune responses that developed following vaccination with the 19 kDa carboxylterminus of the merozoite surface protein 1 (MSP119) in mice that had previ- ously experienced malaria infection. In this study, pre-exposure of mice to Plasmodium yoelii elicited native anti-MSP119 an- tibody responses, which could be boosted by vaccination with recombinant MSP119 . likewise, infection of MSP119-primed mice with Plasmodium yoelii ( P . yoelii) led to an increase of anti-MSP119 antibodies. MSP119 vaccination of malaria pre- exposed mice or immunization by infection/cure of MSP119-primed mice enabled the mice to survive challenge infection, with the former group having slightly lower parasitaemia. The data suggest that exposure to malaria infection primes a natural im- mune response which can be boosted by vaccination. This information is relevant to the development of a vaccine for use in individuals living in malaria-endemic areas.
基金supported by the National Natural Science Foundation of China(81271863,81361120405)the Key Research Program of the Chinese Academy of Sciences(KJZD-EW-L01)
文摘Both eukaryotic and prokaryotic pathogens infect the host stably via an immune evasion mecha- nism termed mutually exclusive expression. Nowadays, little is known about this epigenetic mechanism, largely limiting the understanding of pathogenesis of many bacterial, fungal and protozoan pathogens and therefore the development of novel drugs and vaccines. In the most severe malaria parasite, Plasrnodiurn falciparum, there is a major virulence gene family termed vat, by which the variant antigen PfEMP1 is encoded and expressed on the surface of parasite-infected erythrocytes. Each parasite carries about 60 anti- genically various vat genes, however, only one of which is expressed at a given time during infection. P. falciparum expresses PfEMP1s in this clonally variant manner to bind to different human endothelial re- ceptors, allowing the infected erythrocytes to sequester in tissues to escape the host＇s immune response in- cluding spleen killing and humoral immunity. At present, the mechanism of mutually exclusive expression of the var gene family remains largely unknown, even though there is increasing evidence suggesting im- portant roles of the epigenetic regulation involved in vat gene expression. In addition, epigenetic factors were also found in association with transcriptional regulation of other antigenic variant gene families in P. falciparum. In this paper, we review the current understanding of epigenetic regulations of P. falcipa- rum virulence genes with particular views toward the design of novel vaccines, drugs, and diagnosis to ma- laria.
