Amanda Williams

Effects of microflora on the neonatal development of gut mucosal T cells and myeloid cells in the mouse

Colonization with commensal flora in very early life may profoundly influence intestinal lymphoid development and bias later immune responses. We defined gut‐homing T cell phenotypes and the influence of flora on intestinal immune development in mice. Intestinal T cells were phenotyped and quantified in conventional (CV), germfree (GF) and conventionalized germfree (GF/CV) neonatal mice by immunohistochemistry. Mucosal adressin cell adhesion molecule 1 (MAdCAM‐1) was expressed by mucosal vessels at birth in CV and GF mice and was more prevalent in CV than GF small intestine, but was distributed similarly and did not change with age. Less MAdCAM‐1 was expressed in the colon; its distribution became restricted after weaning, with no difference between CV and GF mice. CD3+β7+ cells were present in similar numbers in CV and GF intestine at birth. They were CD62L– in CV mice and were accompanied by further CD3+β7+CD62L– T cells as development progressed, but in GF and GF/CV intestine they expressed CD62L and numbers did not change. IEL numbers increased at weaning in CV mice in both small and large intestine, but showed delayed development in GF intestine. Macrophages were present at high levels from birth in GF intestine, but dendritic cells did not develop until dayu200316. Thus, fetus‐derived T cells seed the intestinal lamina propria before birth via β–MadCAM interactions. Their activation status depends on the microbiological status of the dam, and without a commensal flora they remain naive. We propose that these cells regulate antigen responsiveness of the developing mucosal T cell pool.

Intestinal αβ T Cells Differentiate and Rearrange Antigen Receptor Genes In Situ in the Human Infant

Intestinal Ag exposure during neonatal life influences appropriate adult immune responses. To define the mechanisms shaping the T cell repertoire during this period, we examined T cell differentiation and receptor diversity in the intestine of human infants. Developmental phenotypes of intraepithelial and lamina propria intestinal T cells from infants aged 1 day to 2 years were assessed ex vivo by flow cytometry and in situ by triple-fluorescent immunohistochemistry. Gene recombination-specific enzymes were assessed by PCR. TCR β-chain V region gene diversity was determined by sequencing. Several different early lineage T cell populations were present neonatally: CD3+4−8− T cells were present at birth and numbers decreased during the neonatal period; CD3+4+8+ T cells were present in low numbers throughout infancy; and CD3+4+8− or CD3+4−8+ T cells increased with age. Very early lineage T cells, CD3−2−7+ and CD3−2+7+, were present neonatally, but were essentially absent at 1 year. Most lamina propria T cells differentiated rapidly after birth, but maturation of intraepithelial T cells took place over 1 year. Intestinal samples from infants less than 6 mo old contained transcripts of T early α and TdT, and 15 of 19 infant samples contained mRNA for RAG-1, some coexpressing RAG-2. TCR β-chain repertoires were polyclonal in infants. Immature T cells, pre-T cells, and genes involved in T cell recombination were found in the intestine during infancy. T cell differentiation occurs within the neonatal human intestine, and the TCR repertoire of these developing immature T cells is likely to be influenced by luminal Ags. Thus, mucosal T cell responsiveness to environmental Ag is shaped in situ during early life.

An eye for the I: Preferential attention to the eyes of ingroup members.

Human faces, and more specifically the eyes, play a crucial role in social and nonverbal communication because they signal valuable information about others. It is therefore surprising that few studies have investigated the impact of intergroup contexts and motivations on attention to the eyes of ingroup and outgroup members. Four experiments investigated differences in eye gaze to racial and novel ingroups using eye tracker technology. Whereas Studies 1 and 3 demonstrated that White participants attended more to the eyes of White compared to Black targets, Study 2 showed a similar pattern of attention to the eyes of novel ingroup and outgroup faces. Studies 3 and 4 also provided new evidence that eye gaze is flexible and can be meaningfully influenced by current motivations. Specifically, instructions to individuate specific social categories increased attention to the eyes of target group members. Furthermore, the latter experiments demonstrated that preferential attention to the eyes of ingroup members predicted important intergroup biases such as recognition of ingroup over outgroup faces (i.e., the own-race bias; Study 3) and willingness to interact with outgroup members (Study 4). The implication of these findings for general theorizing on face perception, individuation processes, and intergroup relations are discussed.

Race Essentialism and Social Contextual Differences in Children's Racial Stereotyping

The authors explored the differential emergence and correlates of racial stereotyping in 136 children ages 4-11xa0years across two broad social contexts: Hawaii and Massachusetts. Children completed measures assessing race salience, race essentialism, and in-group and out-group stereotyping. Results indicated that the type of racial stereotypes emerging with age was context dependent. In both contexts in-group stereotyping increased with age. In contrast, there was only an age-related increase in out-group stereotyping in Massachusetts. Older children in Massachusetts reported more essentialist thinking (i.e., believing that race cannot change) than their counterparts in Hawaii, which explained their higher out-group stereotyping. These results provide insight into the factors that may shape contextual differences in racial stereotyping.

Tumour necrosis factor-alpha (TNF-α) transcription and translation in the CD4+ T cell-transplanted scid mouse model of colitis

The adoptive transfer of activated CD4+α/β T cell blasts from the spleens of immunocompetent C.B‐17+/+ or BALB/cdm2 mice into C.B‐17scid/scid (scid) mice induces a colitis in the scid recipient within 8 weeks, which progresses to severe disease within 16 weeks. T cells isolated from recipient colon show a Th1 cytokine phenotype. We have examined the relationship between the phenotype of the cellular infiltrate and the transcription and translation of the proinflammatory cytokine TNF‐α. The techniques of double indirect immunohistology and in situ hybridization using digoxigenin‐labelled riboprobes were used. The prominent myeloid cell infiltrate in diseased tissues comprised F4/80+, Mac‐l+ macrophages, neutrophils, dendritic cells and activated macrophages. TNF‐α transcription and translation were associated with activated macrophages in the lamina propria. Activated macrophages transcribing and translating TNF‐α were clustered in areas of tissue destruction. Crypt epithelium of inflamed tissues transcribed TNF‐α at a very early stage of the disease process, but translation of TNF‐α protein could only be found in advanced epithelial dysplasia. This indicates differential post‐transcriptional control of TNF‐α in activated macrophages and the epithelium.

Can 11β-hydroxysteroid dehydrogenase activity predict the sensitivity of bone to therapeutic glucocorticoids in inflammatory bowel disease?

In healthy individuals measures of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) enzyme activity predict the change in bone formation markers in response to therapeutic glucocorticoids. It is unclear whether these measures remain predictive in inflammatory disease. We therefore examined whether 11β-HSD1 activity predicts changes in bone markers and bone mineral density (BMD) in patients with inflammatory bowel disease (IBD) treated with therapeutic glucocorticoids. Prospective and cross-sectional studies were carried out in patients attending a gastroenterology clinic with active (nxa0=xa039) or clinically inactive (nxa0=xa034) IBD and healthy controls (nxa0=xa051). Urinary corticosteroid metabolite profiles were obtained on a spot urine sample and total corticosteroid metabolite excretion and 11β-HSD1 activity (measured as the ratio of tetrahydrocortisol to tetrahydrocortisone metabolites, [THF+alloTHF]/THE) determined. Patients with active disease were treated with an 8-week reducing course of oral prednisolone. The (THF+alloTHF)/THE ratio was significantly increased in patients with IBD, even those in clinical remission. The baseline (THF+alloTHF)/THE ratio failed to predict the decrease in bone formation markers or hip BMD. Measures of 11β-HSD activity do not predict bone loss during glucocorticoid treatment of active IBD, probably due to disease-related increases in 11β-HSD1 activity. Our observation of elevated 11β-HSD1 activity in clinically inactive IBD implicates gastrointestinal glucocorticoid activation in the maintenance of disease remission.

Racial microaggressions and perceptions of Internet memes

Although more blatant forms of discrimination have declined, racial prejudice continues to manifest itself in subtle ways. For example, People of Color experience racial microaggressions (i.e., subtle slights or put downs) in their face-to-face interactions (Nadal, 2011) and in online contexts (Clark etźal., 2011). This study investigates whether experiencing subtle racial discrimination offline can influence perceptions of online content, specifically racial themed Internet memes. Results indicate that although both People of Color and Whites viewed racial themed memes to be more offensive than non-racial themed memes (control images), for People of Color the ratings of racial themed memes were predicted by previous discrimination; those who reported experiencing more racial microaggressions in everyday settings rated racial themed memes as more offensive. The same pattern of results did not emerge for ratings of non-racial themed memes or for White participants. These results provide initial evidence that experiencing racial microaggressions in offline interactions may lead individuals from racial minority groups to be more likely to perceive racial discrimination in online settings. Non-Whites experienced more racial microaggressions than Whites.Regardless of race, racist memes were rated as more offensive than non-racist memes.For non-Whites, experiencing microaggressions predicted ratings of racist memes.This same relationship did not emerge for Whites.

Transforming Growth Factor-β Messenger RNA and Protein in Murine Colitis

Using a CD4+ T-cell-transplanted SCID mouse model of colitis, we have analyzed TGF-β transcription and translation in advanced disease. By in situ hybridization, the epithelium of both control and inflamed tissues transcribed TGF-β1 and TGF-β3 mRNAs, but both were expressed significantly farther along the crypt axis in disease. Control lamina propria cells transcribed little TGF-β1 or TGF-β3 mRNA, but in inflamed tissues many cells expressed mRNA for both isoforms. No TGF-β2 message was detected in either control or inflamed tissues. Immunohistochemistry for latent and active TGF-β1 showed that all cells produced perinuclear latent TGF-β1. The epithelial cell basal latent protein resulted in only low levels of subepithelial active protein, which co-localized with collagen IV and laminin in diseased and control tissue. Infiltrating cells expressed very low levels of active TGF-β. By ELISA, very low levels (0–69 pg/mg) of soluble total or active TGF-β were detected in hypotonic tissue lysates. TGF-β1 and TGF-β3 are produced by SCID mouse colon and transcription is increased in the colitis caused by transplantation of CD4+ T-cells, but this does not result in high levels of soluble active protein. Low levels of active TGF-β may be a factor contributing to unresolved inflammation.

The Reliability of Child-Friendly Race-Attitude Implicit Association Tests

Implicit attitudes are evaluations that are made automatically, unconsciously, unintentionally, or without conscious and deliberative processing (Nosek et al., 2007; Gawronski and De Houwer, 2014). For the last two decades implicit measures have been developed and used to assess people’s attitudes and social cognition, with the most widely used measure being the Implicit Association Test (IAT; Greenwald et al., 2003). This measure has been used extensively to assess racial biases and a number of studies have examined the reliability of the IAT when administered to adults (Cunningham et al., 2001; Gawronski, 2002; Greenwald et al., 2003; Nosek et al., 2005; Nosek and Smyth, 2007; Bar-Anan and Nosek, 2014). In recent years, the IAT has also been modified for use with children. Despite the potential of this measure to provide insight into the early emergence of implicit racial attitudes, little is known about the psychometric properties of these modified child-friendly IATs (Child-IATs). In the current research we examined the internal consistency of race-attitude Child-IATs when either reduced (Study 1) or traditional-length (Study 2) versions were administered to children (Studies 1 and 2) and adults (Study 2). We also examined the test–retest reliability of this measure with both child and adult participants (Study 2). We found that these measures demonstrate an internal consistency comparable to what has been seen in previous research with adults. In addition, the internal consistency of traditional-length Child-IATs completed in succession depended on the order in which they were completed; the first Child-IAT demonstrated higher internal consistency than the second for both children and adults (Study 2). Finally, we provide the first evidence that the test–retest reliability of the Child-IAT is comparable to what has been found previously with adults (Study 2). The implications of these findings for future research examining children’s implicit social cognition are discussed.

IL-6 May Modulate the Skeletal Response to Glucocorticoids During Exacerbations of Inflammatory Bowel Disease

Whether inflammatory cytokines affect the skeletal response to glucocorticoid (GC) treatment is unclear. Our objectives were to (1) identify the cytokine(s) elevated during exacerbations of inflammatory bowel disease (IBD); (2) determine whether the cytokine(s) identified in this way is related to systemic GC sensitivity; and (3) examine whether cytokines and/or measures of GC sensitivity are related to changes in bone formation or resorption following GC therapy. We designed a combined cross-sectional and prospective study, including patients with active (nxa0=xa031) and inactive (nxa0=xa034) IBD as well as controls (nxa0=xa029). We assessed circulating concentrations of cytokines, PINP and βCTX, as well as GC sensitivity in peripheral blood mononuclear cells. IL-6 was the only cytokine increased in active IBD, 2.35 (2.63) versus 1.64 (1.21) versus 1.31 (2.79) pg/μl active IBD, inactive IBD, and controls, respectively (median [interquartile range]) (Pxa0=xa00.03, ANOVA). IL-6 was positively related to magnitude of GC sensitivity (betaxa0=xa00.02, 95% CI 0.008–0.04, Pxa0=xa00.005). Following treatment with GC in active IBD, PINP decreased (Pxa0<xa00.001), whereas βCTX showed no significant change (Pxa0=xa00.2). Subsequently, multiple regression analyses revealed that plasma IL-6 concentrations were inversely related to the extent of PINP suppression following GC (betaxa0=xa03.3, 95% CI 0.2–6.4, Pxa0=xa00.04, adjusted for baseline PINP and duration of GC treatment), while no association was observed with GC sensitivity. In conclusion, IL-6 is elevated in active IBD and may protect against GC-induced suppression of bone formation via a mechanism which appears to be independent of systemic GC sensitivity.