Langerhans cells protect from allergic contact dermatitis in mice by tolerizing CD8+ T cells and activating Foxp3+ regulatory T cells

Allergic contact dermatitis is the most frequent occupational disease in industrialized countries. It is caused by CD8(+) T cell-mediated contact hypersensitivity (CHS) reactions triggered at the site of contact by a variety of chemicals, also known as weak haptens, present in fragrances, dyes, metals, preservatives, and drugs. Despite the myriad of potentially allergenic substances that can penetrate the skin, sensitization is relatively rare and immune tolerance to the substance is often induced by as yet poorly understood mechanisms. Here we show, using the innocuous chemical 2,4-dinitrothiocyanobenzene (DNTB), that cutaneous immune tolerance in mice critically depends on epidermal Langerhans cells (LCs), which capture DNTB and migrate to lymph nodes for direct presentation to CD8(+) T cells. Depletion and adoptive transfer experiments revealed that LCs conferred protection from development of CHS by a mechanism involving both anergy and deletion of allergen-specific CD8(+) T cells and activation of a population of T cells identified as ICOS(+)CD4(+)Foxp3(+) Tregs. Our findings highlight the critical role of LCs in tolerance induction in mice to the prototype innocuous hapten DNTB and suggest that strategies targeting LCs might be valuable for prevention of cutaneous allergy.

Students' awareness of and attitudes to AIDS

Students' attitudes to and knowledge and awareness of the acquired immune deficiency syndrome (AIDS) was assessed by questionnaire. The recent information campaign reached a high proportion of the sample of 1063 students and television was the most memorable medium. Students were generally aware that AIDS was not associated with social contact but there was confusion about the risk of infection from donating or receiving blood, with 17.9% of blood donors now less willing to donate blood. Most of the students were aware that the condom reduces the risk of spread of AIDS sexually but there was no indication of widespread condom usage among the 399 students who admitted they were sexually active; 39.1% of this group used condoms alone or with other protection. Almost half the sample (47.6%) would like to have the opportunity to have their blood tested for the AIDS virus; 96 students would prefer this to be at a clinic and 59 of them would not wish their family doctor to know the result. A high proportion of the sample considered that AIDS victims should be cared for at home or in a special hospice.

Behavioural consequences of imagining intergroup contact with stigmatized outgroups

We investigated whether imagining contact with an outgroup member would change intergroup behaviour. Participants who had imagined a positive interaction with an outgroup member or an unspecified stranger were told that they were about to take part in a discussion task with an outgroup member. They were taken to a room and asked to set out two chairs ready for the discussion while the experimenter left, ostensibly to find the other participant. The distance between the two chairs was then measured. Undergraduate students who imagined talking to an obese individual (Experiment 1) or a Muslim individual (Experiment 2) placed the chairs significantly closer than those in the control condition. They also reported more positive feelings and beliefs regarding Muslims. These findings highlight an important practical application of imagined contact: preparing people for successful face-to-face contact.

From imagery to intention: A dual route model of imagined contact effects

Imagined intergroup contact (Crisp & R. Turner, 2009) is a new indirect contact strategy for promoting tolerance and more positive intergroup relations. In this chapter, we review existing research on imagined contact and propose two routes-cognitive and affective-through which it can exert a positive influence on contact-related attitudes and intentions. We first review research that has established the beneficial impacts of imagined contact on intergroup attitudes via reduced intergroup anxiety, supporting its efficacy as an intervention where there exists little or no opportunity for direct contact. We then review more recent research showing that imagined contact not only improves attitudes, but can also enhance intentions to engage in future contact. These studies suggest that contact imagery provides a behavioural script that forms the cognitive basis for subsequent judgements about future contact intentions. Collectively, the findings from this research programme support the idea that imagined contact can complement more direct forms of contact-providing a way of initially encouraging an interest in engaging positively with outgroups before introducing face-to-face encounters. We discuss the implications of these findings for future theory and research, and how they can inform prejudice-reduction interventions seeking to capitalise on the beneficial effects of mental imagery.

Imagining intergroup contact reduces implicit prejudice

Recent research has demonstrated that imagining intergroup contact can be sufficient to reduce explicit prejudice directed towards out-groups. In this research, we examined the impact of contact-related mental imagery on implicit prejudice as measured by the implicit association test. We found that, relative to a control condition, young participants who imagined talking to an elderly stranger subsequently showed more positive implicit attitudes towards elderly people in general. In a second study, we demonstrated that, relative to a control condition, non-Muslim participants who imagined talking to a Muslim stranger subsequently showed more positive implicit attitudes towards Muslims in general. We discuss the implications of these findings for furthering the application of indirect contact strategies aimed at improving intergroup relations.

A test of the extended intergroup contact hypothesis: The mediating role of intergroup anxiety, perceived ingroup and outgroup norms, and inclusion of the outgroup in the self

S. C. Wright, A. Aron, T. McLaughlin-Volpe, and S. A. Ropp (1997) proposed that the benefits associated with cross-group friendship might also stem from vicarious experiences of friendship. Extended contact was proposed to reduce prejudice by reducing intergroup anxiety, by generating perceptions of positive ingroup and outgroup norms regarding the other group, and through inclusion of the outgroup in the self. This article documents the first test of Wright et al.'s model, which used structural equation modeling among two independent samples in the context of South Asian-White relations in the United Kingdom. Supporting the model, all four variables mediated the relationship between extended contact and outgroup attitude, controlling for the effect of direct contact. A number of alternative models were ruled out, indicating that the four mediators operate concurrently rather than predicting one another.

Can Imagined Interactions Produce Positive Perceptions? Reducing Prejudice Through Simulated Social Contact

The contact hypothesis states that, under the right conditions, contact between members of different groups leads to more positive intergroup relations. The authors track recent trends in contact theory to the emergence of extended, or indirect, forms of contact. These advances lead to an intriguing proposition: that simply imagining intergroup interactions can produce more positive perceptions of outgroups. The authors discuss empirical research supporting the imagined contact proposition and find it to be an approach that is at once deceptively simple and remarkably effective. Encouraging people to mentally simulate a positive intergroup encounter leads to improved outgroup attitudes and reduced stereotyping. It curtails intergroup anxiety and extends the attribution of perceivers' positive traits to others. The authors describe the advantages and disadvantages of imagined contact compared to conventional strategies, outline an agenda for future research, and discuss applications for policymakers and educators in their efforts to encourage more positive intergroup relations.

Constrained adoptive parenthood and family transition: Adopters' experience of unplanned birth family contact in adolescence

Adoption policy in the UK emphasizes its role in providing secure, permanent relationships to children in care who are unable to live with their birth families. Adoptive parents are crucial in providing this life-long, stable experience of family for these vulnerable children. This paper explores the experience of adoptive parenthood in the context of changes to adoptive kinship relationships brought about by new, unplanned contact with birth family during their child's middle adolescence. This contact was initiated via informal social networks and/or social media, with older birth siblings instrumental in negotiating renewed relationships. The contact precipitated a transition in adoptive family life resulting in emotional challenges and changes in parent/child relationships, which were experienced as additional to the normative transitions expected during adolescence. Parental concern as a dominant theme was founded in the child and birth sibling's stage of adolescence, coupled with constraints on adoptive parenthood imposed by the use of social media, by perceived professional attitudes and by parental social cognitions about the importance of birth ties. Adoptive parents' accounts are interpreted with reference to family life-cycle theory and implications are suggested for professional support of adoptive kinship relationships.

Contact and context: sharing education and building relationships in a divided society

One approach to tackling problems of division in society has been to promote collaboration and engagement between schools separated on ethno-religious lines. Based on some variant of contact theory, the received wisdom is that inter-group encounters can contribute to prejudice reduction and promote more harmonious relationships. Evidence to support this analysis is convincing; however, relatively little is known about the environmental factors that impede or enhance the potential for contact in different contexts. The importance of understanding such factors is underscored in divided jurisdictions, where separate education has been linked to the perpetuation of division and hostility. This paper adopts a qualitative approach to exploring the impact of two inter-school initiatives in Northern Ireland. The projects are located in contrasting socio-political and demographic environments, and research findings point to very different contact outcomes for participants in each. Seemingly relevant factors include the degree of congruence between school and community norms and values, the opportunity to develop relationships outside the school context, the relationships developed between the schools and local communities and the historical, political and social referents used by individuals to navigate the contact experience. The paper concludes with some reflections on factors that may help foster social harmony and on potential policy implications of the findings.

Pathogenic Yersinia enterocolitica strains increase the outer membrane permeability in response to environmental stimuli by modulating lipopolysaccharide fluidity and lipid A structure

Pathogenic biotypes of Yersinia enterocolitica (serotypes O:3, O:8, O:9, and O:13), but not environmental biotypes (serotypes O:5, O:6, O:7,8, and O:7,8,13,19), increased their permeability to hydrophobic probes when they were grown at pH 5.5 or in EGTA-supplemented (Ca(2+)-restricted) media at 37 degrees C. A similar observation was also made when representative strains of serotypes O:8 and O:5 were tested after brief contact with human monocytes. The increase in permeability was independent of the virulence plasmid. The role of lipopolysaccharide (LPS) in this phenomenon was examined by using Y. enterocolitica serotype O:8. LPS aggregates of bacteria grown in acidic or EGTA-supplemented broth took up more N-phenylnaphthylamine than LPS aggregates of bacteria grown in standard broth and also showed a marked increase in acyl chain fluidity which correlated with permeability, as determined by measurements obtained in the presence of hydrophobic dyes. No significant changes in O-antigen polymerization were observed, but lipid A acylation changed depending on the growth conditions. In standard medium at 37 degrees C, there were hexa-, penta-, and tetraacyl lipid A forms, and the pentaacyl form was dominant. The amount of tetraacyl lipid A increased in EGTA-supplemented and acidic media, and hexaacyl lipid A almost disappeared under the latter conditions. Our results suggest that pathogenic Y. enterocolitica strains modulate lipid A acylation coordinately with expression of virulence proteins, thus reducing LPS packing and increasing outer membrane permeability. The changes in permeability, LPS acyl chain fluidity, and lipid A acylation in pathogenic Y. enterocolitica strains approximate the characteristics in Yersinia pseudotuberculosis and Yersinia pestis and suggest that there is a common outer membrane pattern associated with pathogenicity.

Use of contact lenses in patients with filtering blebs

Purpose: The purpose of this study was to describe the outcome of patients with filtering blebs who were fit with contact lenses. Methods: We retrospectively studied patients with filtering blebs secondary to glaucoma or cataract surgery who were fit with contact lenses. Eight eyes from seven patients were identified. Results: Five patients (six eyes) were fit with gas permeable contact lenses and two patients (two eyes) were fit with soft contact lenses. Successful fits were achieved in all patients. No complications were observed after a mean follow-up of 64.6±28.5 months. Conclusions: No significant complications were recorded in our series of patients with filtering blebs who were fit with contact lenses. We think that when indications for fitting contact lenses are justified, patients with filtering blebs are acceptable candidates for contact lens use. However, adequate selection of cases, careful contact lens fitting, patient education, and close follow-up are necessary.