Candida albicans morphology and dendritic cell subsets determine T helper cell differentiation.

Candida albicans is a dimorphic fungus responsible for chronic mucocutaneous and systemic infections. Mucocutaneous immunity to C. albicans requires T helper 17 (Th17) cell differentiation that is thought to depend on recognition of filamentous C. albicans. Systemic immunity is considered T cell independent. Using a murine skin infection model, we compared T helper cell responses to yeast and filamentous C. albicans. We found that only yeast induced Th17 cell responses through a mechanism that required Dectin-1-mediated expression of interleukin-6 (IL-6) by Langerhans cells. Filamentous forms induced Th1 without Th17 cell responses due to the absence of Dectin-1 ligation. Notably, Th17 cell responses provided protection against cutaneous infection while Th1 cell responses provided protection against systemic infection. Thus, C. albicans morphology drives distinct T helper cell responses that provide tissue-specific protection. These findings provide insight into compartmentalization of Th cell responses and C. albicans pathogenesis and have critical implications for vaccine strategies.

Skin dendritic cells induce follicular helper T cells and protective humoral immune responses.

BACKGROUND: The contribution of individual subsets of dendritic cells (DCs) to generation of adaptive immunity is central to understanding immune homeostasis and protective immune responses. OBJECTIVE: We sought to define functions for steady-state skin DCs. METHODS: We present an approach in which we restrict antigen presentation to individual DC subsets in the skin and monitor the effects on endogenous antigen-specific CD4(+) T- and B-cell responses. RESULTS: Presentation of foreign antigen by Langerhans cells (LC) in the absence of exogenous adjuvant led to a large expansion of T follicular helper (TFH) cells. This was accompanied by B-cell activation, germinal center formation, and protective antibody responses against influenza. The expansion of TFH cells and antibody responses could be elicited by both systemic and topical skin immunization. TFH cell induction was not restricted to LCs and occurred in response to antigen presentation by CD103(+) dermal DCs. CD103(+) DCs, despite inducing similar TFH responses as LCs, were less efficient in induction of germinal center B cells and humoral immune responses. We also found that skin DCs are sufficient to expand CXCR5(+) TFH cells through an IL-6- and IFN-α/ß receptor-independent mechanism, but B cells were required for sustained Bcl-6(+) expression. CONCLUSIONS: These data demonstrate that a major unappreciated function of skin DCs is their promotion of TFH cells and humoral immune responses that potentially represent an efficient approach for vaccination.

"What's My Line?": Pseudo-Improvised Teaching When the Clinical Teaching Script Is Blank.

ABSTRACT: Commitment to clinical education often requires significant forethought and attention to provide a comprehensive learning experience for trainees. In these settings, teaching is typically time-limited, prompted by a clinical scenario, and requires preparation. However, it is not uncommon for teachers to have insufficient time to prepare or to encounter a clinical scenario in which they have not yet developed a teaching script.In this article, the authors share 5 categories of teaching techniques that instructors can pull from regardless of the prompt or busyness of the clinical setting and that are ideal for using when the teaching script is "blank." They call this approach of having scenario-independent teaching techniques ready to be applied with minimal preparation, "pseudo-improvised teaching."Drawing from the literature, their own experience, and borrowing from improvisational theater, the authors share a toolkit of pseudo-improvised teaching techniques spanning from pathophysiology to clinical skills to work-life integration. In addition to highlighting several techniques, they describe models of meta-structure for teaching in which the use of themes for the day (i.e., longitudinal themes) and routines can ease some of the cognitive load felt by both learners and educators.

Weight Status and Weight Perception in Relation to Mental Distress and Psychosocial Protective Factors Among Adolescents.

OBJECTIVE: To measure how weight status and weight perception relate to mental distress and psychosocial protective factors in adolescents. METHODS: Adolescents in 8th, 9th, and 11th grade participating in the 2013 Minnesota Student Survey (N = 122,180) were classified on the basis of weight perception (overweight or not overweight) and weight status (not overweight, overweight, obese). Bivariate tests were used to assess the relationship of weight status and weight perception with internal mental distress, and generalized linear models were used to measure the association between weight status and weight perception with psychosocial protective factors including parent, school, and friend connectedness, social competency, and positive identity. Logistic regressions measured the relationship between psychosocial protective factors and internal mental distress. RESULTS: Prevalence of internal mental distress ranged from 14.5% for overweight boys who perceived themselves as not overweight to 55.0% for girls who were not overweight but self-perceived as overweight. Across all weight-status categories, adolescents who perceived themselves as overweight, compared to those who did not, had higher internal mental distress and lower mean levels of psychosocial protective factors. All psychosocial protective factors were related to lower odds of internal mental distress, with significant small differences by weight status and weight perception. CONCLUSIONS: Weight status and weight perception affected both mental distress and psychosocial protective factors. Those who perceived themselves as overweight, regardless of weight status, had the highest prevalence of mental distress and the lowest levels of psychosocial protective factors. Health care providers should consider screening for weight perception to provide a tailored approach to adolescent care.