Induction of NK cytotoxicity of canine CD5/CD21 double negative cells by CD5lo NK cells
Date Issued
2011
Date
2011
Author(s)
Chang, Chun-Pei
Abstract
Natural killer (NK) cells play important roles in both early protection against viruses or tumor cells and in regulating immune functions. However, only a few studies have focused on the characterization of canine NK cells. We previously demonstrated that canine peripheral blood lymphocytes with low surface CD5 density (CD5lo) are closely associated with NK cell characteristics, and are considered to be an important NK population. NK cells in most mammals do not express T cell markers. However, CD5lo cells expressed surface molecules such as CD3, CD8, and α/βTCR, making canines a unique model to study comparative immunology in NK cells.
In this study, we discovered that although CD5lo (CD5lo-ne) and CD21 double negative cells were originally low in NK cytotoxicity, they became highly activated in NK cytotoxicity when cultured with CD5lo NK cells. The cytotoxicity was not activated as in the culture of other types of cells, such as CD5hi cells and CD21+. The CD5lo-ne population comprises CD5- and CD5hi cells, which were sorted separately by fluorescent density with a FACSAria TM flow cytometer. We first tested CD5- cells and found that these cells were initially low in NK cytotoxicity or after being cultured in IL-2 when CD5lo cells were absent in the culture (4.16±3.51% at ET ratio of 50:1), but as CD5lo cells were added in similar medium, the NK activity became greatly enhanced (22.42±18.07at ET ratio of 50:1). The other population of CD5lo-ne, CD5hi cells, was always NK inactive, no matter whether or not it was cultured alone or with CD5lo cells (3.60±2.92% or 3.07±2.08% at ET ratio of 50:1). We further verified that CD5- cells carrying no CD21 surface molecules, i.e. CD5/CD21 double negative cells were the cell type in CD5- cells population whose NK cytotoxicity was activated by CD5lo cells. This is the first report to present that NK cells enhanced NK-inert cells to become NK cytotoxic. It also concluded that in beagles, besides CD5lo cells, CD5/CD21 double negative cells also exhibited NK activity. However, it depended on the presence of CD5lo cells
Subjects
canine natural killer cells
peripheral blood lymphocytes (PBLs)
lymphokine-activated killers (LAKs)
CD5lo cells
CD5- cells
non-T non-B
natural cytotoxicity
Type
thesis
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