Lung infections caused by the opportunistic pathogenPseudomonas aeruginosa can present as a spectrum of clinical entities from a rapidly fatal pneumonia in a neutropenic patient to a multi-decade bronchitis in patients with cystic fibrosis. P. aeruginosa is ubiquitous in our environment, and one of the most versatile pathogens studied, capable of infecting a number of diverse life forms and surviving harsh environmental factors. It is also able to quickly adapt to new environments, including the lung, where it orchestrates virulence factors to acquire necessary nutrients, and if necessary, turn them off to prevent immune recognition. Despite these capabilities, P. aeruginosa rarely infects healthy human lungs. This is secondary to a highly evolved host defence mechanism that efficiently removes inhaled or aspirated pseudomonads. Many arms of the respiratory host defence have been elucidated using P. aeruginosa as a model pathogen. Human infections with P. aeruginosa have demonstrated the importance of the mechanical barrier functions including mucus clearance, and the innate immune system, including the critical role of the neutrophilic response. As more models of persistent or biofilm P. aeruginosa infections are developed, the role of the adaptive immune response will likely become more evident. Understanding the pathogenesis of P. aeruginosa, and the respiratory host defence response to it has, and will continue to, lead to novel therapeutic strategies to help patients.Key words: biofilm, innate immunity, mucosal immunity, Pseudomonas aeruginosa, respiratory infection. INTRODUCTIONPseudomonas aeruginosa is a common bacterium found in waterborne environments throughout nature.1 It has a large genome containing a myriad of pathogenic and metabolic capabilities allowing it to infect many organisms, including plants, amoebas, nematodes and vertebrate animals.2 Given its pathogenic potential, it is perhaps surprising that human infections from this organism are not more commonplace. Lung infections caused by P. aeruginosa are limited to patients who are immunocompromised, or who have defective mucociliary clearance, previous epithelial injury or foreign body placement. Given its ubiquitous presence in our environment and pathogenic potential, it is clear that a normally functioning host defence is very well adapted to prevent P. aeruginosa infection. Despite this, P. aeruginosa infections can be devastating in the hospitalized or sick. Understanding the failures of the host defence in these patients will help us understand how P. aeruginosa is converted from a common environmental exposure to a deadly pathogen. PSEUDOMONAS AERUGINOSA RESPIRATORY INFECTIONSPseudomonas aeruginosa rarely infects the human lung without an underlying defect in immunity or mechanical barrier. Clinically, P. aeruginosa infections are frequently classified into 'acute' and 'chronic' infections although the distinctions between these groups are not always clear. New acquisition of P. aeruginosa results in symptomology that prompts...

In seeking to support diversity, one challenge lies in adequately supporting and assessing science cognitions in a writing-intensive Biochemistry laboratory course when highly engaged Asian English language learners (Asian ELLs) struggle to communicate and make novice errors in English. Because they may understand advanced science concepts, but are not being adequately assessed for their deeper scientific understanding, we sought and examined interventions. We hypothesized that inquiry strategies, scaffolded learning through peer evaluation, and individualized tools that build writing communication skills would increase confidence. To assess scientific thinking, Linguistic Inquiry Word Count (LIWC) software measured underlying analytic and cognitive features of writing despite grammatical errors. To determine whether interventions improved student experience or learning outcomes, we investigated a cross-sectional sample of cases within experimental groups (n = 19) using a mixed-methods approach. Overall trends of paired t-tests from Asian ELLs’ pre/post surveys showed gains in six measures of writing confidence, with some statistically significant gains in confidence in writing skill (p=0.025) and in theory (p≤0.05). LIWC scores for Asian ELL and native-English-speaking students were comparable except for increased cognitive scores for Asian ELLs and detectable individual differences. An increase in Asian ELLs’ cognitive scores in spring/summer over fall was observed (p = 0.04), likely as a result of greater cognitive processes with language use, inquiry-related interventions, and peer evaluation. Individual cases further elucidated challenges faced by Asian ELL students. LIWC scores of student writing may be useful in determining underlying understanding. Interventions designed to provide support and strengthen the writing of Asian ELL students may also improve their confidence in writing, even if improvement is gradual.

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Worldwide, there are an estimated 216 million cases of malaria annually and of those affected 655,000 will succumb to the disease. Antibody responses to infection have been shown to be critical in limiting infection and disease, but the mechanisms by which these are acquired or lost are poorly understood. Various hypotheses have been proposed for dysfunctional humoral responses including B cell exhaustion, germinal center architectural disruption, parasite antigenic variation and inhibitory innate immune signaling. However, the relative infrequency of malaria specific B cells in the periphery has limited targeted detection of these cells. We present a strategy for phenotypic analyses of malaria specific B cells in peripheral blood using tetramerized biotinylated malaria antigen coupled to phycoerythrin labeled streptavidin, magnetic bead enrichment and cytometric flow analysis. Using this technique, we demonstrate the detection of an antigen specific germinal center reaction in B6 mice after immunization with P.pastoris expressing recombinant Plasmodium falciparum apical membrane antigen-1 and circumsporozoite protein. Preliminary results in humans identified low frequency B cells specific to these two antigens. Overall, our results suggest that this technique will be a valuable tool in studying naturally acquired and vaccine derived malaria specific B cell responses.