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Prion exclusion by antibodies?
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to survive. A body of evidence suggests that CD4+ T cells initiate autoimmune responses against myelin antigens in MS, and according to Markovic-Plese and colleagues, the subset they have found might play an important role in the inflammatory response within the central nervous system seen in MS. These so-called ‘costimulation-independent’ T cells have a CD4+CD28– phenotype and display prominent growth characteristics and increased survival after activation. Their ability to bypass normal regulation could be due to the fact that they persistently lack the expression of the important costimulatory molecule CTLA-4 on their surface. The team postulate that it could be that this group of independent T cells have the potential to initiate the autoimmune responses that underly the pathology seen in MS. J. Clin. Invest. (2001) 108, 1185-1194 AL
Self-hypnosis boosts immune system Stress has long been suspected to hinder immune responses. Researchers from Ohio State University in Columbus, USA have now reported that the stressrelieving technique of self-hypnosis can help to protect against the adverse effects of stress on the immune system. In a study of medical students under exam-time stress, investigators found that those who received hypnoticrelaxation training did not show the same reduction in the activity of T cells and other immune-system defenses as their untrained colleagues. The investigators found that during exam time, the self-hypnosis students exhibited stronger immune responses compared with students who did not learn the technique. Moreover, the more often students practised the relaxation strategy, the stronger their immune response became. J. Consult. Clin. Psychol. (2001) 69, 674–682 SW
Hormonal link between early miscarriage and Fas ligand Normally, corticotropin-releasing hormone (CRH) is secreted by the mother and the embryo soon after it implants itself in the http://immunology.trends.com
TRENDS in Immunology Vol.22 No.12 December 2001
uterus. Without it, researchers have found that the embryo might be vulnerable to attack from the mother’s immune system. CRH triggers the production of Fas ligand (FasL). When activated T cells, a potential threat to the developing embryo, engage FasL they are triggered to die. Thus, rejection of the developing embryo by maternal T cells is prevented by the protective FasL barrier. Blocking the action of CRH inhibited embryo implantation and reduced the number of successful pregnancies. Thus, women who cannot sustain a pregnancy might be unable to control these immune reactions. Nat. Immunol. (2001) 10, 1018–1024 SW
Limited effect of vaccine in foot-and-mouth model Vaccination during the recent foot-andmouth epidemic would have had little effect, according to a recently developed model of the epidemic. Researchers from the University of Edinburgh and Department for Environment, Food and Rural Affairs (DEFRA) developed a model to estimate the regional risk of transmission of the virus amongst livestock. However, when they explored vaccination strategies, they found that although vaccination in the early stages of the epidemic would have been advantageous, culling was more effective at limiting the epidemic. Their analysis showed that vaccination, even at high levels, during the later stages of the epidemic would have had little effect on transmission. Dr Keeling from the University of Edinburgh says that the team is ‘currently following up these initial results with a more extensive analysis of the use of vaccination’. The current policy of local culls was successful in their model, such that the number of infections was reduced by 50% compared with the numbers documented when infected animals alone were killed. Science (2001) 294, 813–817 AL
Prion exclusion by antibodies? Preventing the invasion of the CNS by prions is a challenge. Vaccination with prion proteins was unsuccessful initially because they are not particularly immunogenic.
661
Using a mouse lacking endogenous prion protein, high-affinity IgG1 antibodies have been developed, sequenced, expressed as transgenes and used to breed mouse strains expressing these specific antibodies. In some of these strains, deposition of scrapie in the spleen or CNS was prevented by the antibodies. This technique suggests that the refinement of B-cell responses, by whatever means, might offer a route to limit the invasion of the CNS by prion agents. Furthermore, this murine model suggested that such a process does not induce autoimmunity necessarily. Science (2001) 294, 178–182 CM
Mapping dendritic-cell responses
A crucial and early element in host responses is determined by dendritic cells, but how variable are their responses to the patterns of molecules presented to them by different pathogens? Genetic expression in dendritic cells has been assayed by isolating mRNA following culture with appropriate stimuli, and analyzing this mRNA on Affymetrix oligonucleotide arrays. Huang and colleagues have demonstrated distinctive responses to E. coli, influenza and Candida albicans, involving 1330 genes, with an overlapping set of some 166 genes activated in all situations. Such wide variation in dendriticcell responses must have a significant effect on the characteristics and dynamics of the subsequent immune response. Science (2001) 294, 870–875 CM
Antibiotics increase risk of intestinal problems in infants Giving young infants the antibiotic erythromycin, particularly in the first two weeks of life, increases their risk of the gastrointestinal complication infantile hypertrophic pyloric
1471-4906/01/$ – see front matter © 2001 Elsevier Science Ltd. All rights reserved.
to survive. A body of evidence suggests that CD4+ T cells initiate autoimmune responses against myelin antigens in MS, and according to Markovic-Plese and colleagues, the subset they have found might play an important role in the inflammatory response within the central nervous system seen in MS. These so-called ‘costimulation-independent’ T cells have a CD4+CD28– phenotype and display prominent growth characteristics and increased survival after activation. Their ability to bypass normal regulation could be due to the fact that they persistently lack the expression of the important costimulatory molecule CTLA-4 on their surface. The team postulate that it could be that this group of independent T cells have the potential to initiate the autoimmune responses that underly the pathology seen in MS. J. Clin. Invest. (2001) 108, 1185-1194 AL
Self-hypnosis boosts immune system Stress has long been suspected to hinder immune responses. Researchers from Ohio State University in Columbus, USA have now reported that the stressrelieving technique of self-hypnosis can help to protect against the adverse effects of stress on the immune system. In a study of medical students under exam-time stress, investigators found that those who received hypnoticrelaxation training did not show the same reduction in the activity of T cells and other immune-system defenses as their untrained colleagues. The investigators found that during exam time, the self-hypnosis students exhibited stronger immune responses compared with students who did not learn the technique. Moreover, the more often students practised the relaxation strategy, the stronger their immune response became. J. Consult. Clin. Psychol. (2001) 69, 674–682 SW
Hormonal link between early miscarriage and Fas ligand Normally, corticotropin-releasing hormone (CRH) is secreted by the mother and the embryo soon after it implants itself in the http://immunology.trends.com
TRENDS in Immunology Vol.22 No.12 December 2001
uterus. Without it, researchers have found that the embryo might be vulnerable to attack from the mother’s immune system. CRH triggers the production of Fas ligand (FasL). When activated T cells, a potential threat to the developing embryo, engage FasL they are triggered to die. Thus, rejection of the developing embryo by maternal T cells is prevented by the protective FasL barrier. Blocking the action of CRH inhibited embryo implantation and reduced the number of successful pregnancies. Thus, women who cannot sustain a pregnancy might be unable to control these immune reactions. Nat. Immunol. (2001) 10, 1018–1024 SW
Limited effect of vaccine in foot-and-mouth model Vaccination during the recent foot-andmouth epidemic would have had little effect, according to a recently developed model of the epidemic. Researchers from the University of Edinburgh and Department for Environment, Food and Rural Affairs (DEFRA) developed a model to estimate the regional risk of transmission of the virus amongst livestock. However, when they explored vaccination strategies, they found that although vaccination in the early stages of the epidemic would have been advantageous, culling was more effective at limiting the epidemic. Their analysis showed that vaccination, even at high levels, during the later stages of the epidemic would have had little effect on transmission. Dr Keeling from the University of Edinburgh says that the team is ‘currently following up these initial results with a more extensive analysis of the use of vaccination’. The current policy of local culls was successful in their model, such that the number of infections was reduced by 50% compared with the numbers documented when infected animals alone were killed. Science (2001) 294, 813–817 AL
Prion exclusion by antibodies? Preventing the invasion of the CNS by prions is a challenge. Vaccination with prion proteins was unsuccessful initially because they are not particularly immunogenic.
661
Using a mouse lacking endogenous prion protein, high-affinity IgG1 antibodies have been developed, sequenced, expressed as transgenes and used to breed mouse strains expressing these specific antibodies. In some of these strains, deposition of scrapie in the spleen or CNS was prevented by the antibodies. This technique suggests that the refinement of B-cell responses, by whatever means, might offer a route to limit the invasion of the CNS by prion agents. Furthermore, this murine model suggested that such a process does not induce autoimmunity necessarily. Science (2001) 294, 178–182 CM
Mapping dendritic-cell responses
A crucial and early element in host responses is determined by dendritic cells, but how variable are their responses to the patterns of molecules presented to them by different pathogens? Genetic expression in dendritic cells has been assayed by isolating mRNA following culture with appropriate stimuli, and analyzing this mRNA on Affymetrix oligonucleotide arrays. Huang and colleagues have demonstrated distinctive responses to E. coli, influenza and Candida albicans, involving 1330 genes, with an overlapping set of some 166 genes activated in all situations. Such wide variation in dendriticcell responses must have a significant effect on the characteristics and dynamics of the subsequent immune response. Science (2001) 294, 870–875 CM
Antibiotics increase risk of intestinal problems in infants Giving young infants the antibiotic erythromycin, particularly in the first two weeks of life, increases their risk of the gastrointestinal complication infantile hypertrophic pyloric
1471-4906/01/$ – see front matter © 2001 Elsevier Science Ltd. All rights reserved.