A novel CD2 staining-based flow cytometric assay for assessment of natural killer cell cytotoxicity.

BACKGROUND: Assessing cytotoxicity is fundamental to studying natural killer (NK) cell function. Various radioactive and non-radioactive cytotoxicity assays measuring target cell death have been developed. Among these methods, the most commonly used 51 Chromium-release assay (CRA) and flow cytometry-based cytotoxicity assays (FCCs) are the major representatives. Nonetheless, several drawbacks, including dye leakage and the potential effects of prior labeling on cells, curb the broad applicability of the FCCs. METHODS: Here, we report a rapid FCC for quantifying target cell death after co-incubation with NK cells. In this assay, after 4 hours of NK cell-target cell co-incubation, fluorochrome-conjugated CD2 antibody was used to identify NK cells, and SYTOX Green and Annexin V-FITC were further used to detect target cell death in CD2-negative population. In parallel, both CRA and FCC assay using CFSE/ 7-AAD were performed to validate the reproducibility and replicability. RESULTS: We observed that CD2 is exclusively positive on NK cells other than the most common hematological target tumor cells, such as K562, HL60, MOLM13, Raji, NCI-H929, rpmi8226, MM.1S, and KMS11. Assessment of target cell death using the CD2-based FCC shows a significantly higher percent specific lysis of the target cells compared to the standard CRA and the FCC assay using CFSE and 7-AAD. CONCLUSIONS: We demonstrated that this CD2-based FCC is a fast, simple, and reliable method for evaluating NK cell cytotoxicity.

Health needs in Brooklyn's Chinatown: a pilot assessment using rapid participatory appraisal.

BACKGROUND: The relatively new Chinatown of Brooklyn is medically underserved. A pilot assessment of the health needs of this community was conducted using Rapid Participatory Appraisal. METHODS: In-depth interviews with health professionals and community members plus searches of national, state, and local electronic health databases were conducted taking into account multiple determinants of health. RESULTS: Community organization, sociological factors, services, and policy were all partly responsible for unmet health needs, including the lack of an overall community structure related to health. Health concerns of all kinds were exacerbated by poverty, language barriers, immigration status, culture, and the need for acculturation. Significant health assets were present but were not adequate to address needs. DISCUSSION: While each health concern had its own unique identifiable causes, the interaction of these concerns and the limitations of assets at all levels make solutions difficult.