Utility of Surveillance Research to Inform Physical Activity Policy: An Exemplar From Canada.

BACKGROUND: There are several well-known risk factor monitoring systems, but few examples of comprehensive surveillance systems designed specifically to inform physical activity (PA) policy. This paper examines the utility of Canada`s Physical Activity and Sport Monitoring System in guiding policy and practice. METHODS: Indicators were determined in conjunction with government, nongovernmental associations and academics. Serial measures were collected from representative population (telephone interviews, n = 4000 to 11,000) and setting-based (postal surveys, n = 1425 to 4304) surveys. RESULTS: Adult PA was higher in 2014 (47%) than 1998 (37%). The prevalence of knowledge about sufficient PA to meet national guidelines increased (31% to 57%). Most adults (66%) reported having many safe places to walk locally. Having policies to encourage walking and cycling when redeveloping communities increased by community size (5% to 37%). PA promotion was available in 10% to 15% of workplaces. Most parents (64%) provided transportation to support their child's PA. The prevalence of policies mandating daily PE increased 2001 to 2011 (36% to 55%), as did having no policy to hire qualified PE teachers (25% to 34%). CONCLUSIONS: Canada's surveillance system has provided information for guiding policy planning, resource allocation, setting and tracking national goals, assessing changes in PA determinants, and evaluating national campaigns, naturally occurring experiments, and innovative policies.

Disruption of HLA class II antigen presentation in Burkitt lymphoma: implication of a 47,000 MW acid labile protein in CD4+ T-cell recognition.

While Burkitt lymphoma (BL) has a well-known defect in HLA class I-mediated antigen presentation, the exact role of BL-associated HLA class II in generating a poor CD4(+) T-cell response remains unresolved. Here, we found that BL cells are deficient in their ability to optimally stimulate CD4(+) T cells via the HLA class II pathway. This defect in CD4(+) T-cell recognition was not associated with low levels of co-stimulatory molecules on BL cells, as addition of external co-stimulation failed to elicit CD4(+) T-cell activation by BL. Further, the defect was not caused by faulty antigen/class II interaction, because antigenic peptides bound with measurable affinity to BL-associated class II molecules. Interestingly, functional class II-peptide complexes were formed at acidic pH 5·5, which restored immune recognition. Acidic buffer (pH 5·5) eluate from BL cells contained molecules that impaired class II-mediated antigen presentation and CD4(+) T-cell recognition. Biochemical analysis showed that these molecules were greater than 30,000 molecular weight in size, and proteinaceous in nature. In addition, BL was found to have decreased expression of a 47,000 molecular weight enolase-like molecule that enhances class II-mediated antigen presentation in B cells, macrophages and dendritic cells, but not in BL cells. These findings demonstrate that BL likely has multiple defects in HLA class II-mediated antigen presentation and immune recognition, which may be exploited for future immunotherapies.