Switch to
| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
11
|
| pubmed:dateCreated |
1995-6-22
|
| pubmed:abstractText |
Alveolar macrophages form the first line of defense against inhaled droplets containing Mycobacterium tuberculosis by controlling mycobacterial growth and regulating T cell responses. CD4+ and gamma delta T cells, two major T cell subsets activated by M. tuberculosis, require accessory cells for activation. However, the ability of alveolar macrophages to function as accessory cells for T cell activation remains controversial. We sought to determine the ability of alveolar macrophages to serve as accessory cells for resting (HLA-DR-, IL-2R-) and activated (HLA-DR+, IL-2R+) gamma delta T cells in response to M. tuberculosis and its Ag, and to compare accessory cell function for gamma delta T cells of alveolar macrophages and blood monocytes obtained from the same donor. Alveolar macrophages were found to serve as accessory cells for both resting and activated gamma delta T cells in response to M. tuberculosis Ag. At high alveolar macrophage to T cell ratios (> 3:1), however, expansion of resting gamma delta T cells was inhibited by alveolar macrophages. The inhibition of resting gamma delta T cells by alveolar macrophages was dose-dependent, required their presence during the first 24 h, and was partially overcome by IL-2. Alveolar macrophages did not inhibit activated gamma delta T cells even at high accessory cell to T cell ratios, and alveolar macrophages functioned as well as monocytes as accessory cells. Monocytes were not inhibitory for either resting or activated gamma delta T cells. These findings support the following model. In the normal alveolus the alveolar macrophage to T cell ratio is > or = 9:1, and therefore the threshold for resting gamma delta T cell activation is likely to be high. Once a nonspecific inflammatory response occurs, such as after invasion by M. tuberculosis, this ratio is altered, favoring gamma delta T cell activation by alveolar macrophages.
|
| pubmed:grant | |
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
AIM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Jun
|
| pubmed:issn |
0022-1767
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:day |
1
|
| pubmed:volume |
154
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
5959-68
|
| pubmed:dateRevised |
2007-11-14
|
| pubmed:meshHeading |
pubmed-meshheading:7751639-Antigen-Presenting Cells,
pubmed-meshheading:7751639-Flow Cytometry,
pubmed-meshheading:7751639-Humans,
pubmed-meshheading:7751639-Lymphocyte Activation,
pubmed-meshheading:7751639-Macrophages, Alveolar,
pubmed-meshheading:7751639-Monocytes,
pubmed-meshheading:7751639-Mycobacterium tuberculosis,
pubmed-meshheading:7751639-Receptors, Antigen, T-Cell, gamma-delta,
pubmed-meshheading:7751639-T-Lymphocyte Subsets
|
| pubmed:year |
1995
|
| pubmed:articleTitle |
Alveolar macrophages as accessory cells for human gamma delta T cells activated by Mycobacterium tuberculosis.
|
| pubmed:affiliation |
Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
|
| pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, U.S. Gov't, Non-P.H.S.,
Research Support, Non-U.S. Gov't
|