Linked Life Data

12782589

Source:http://linkedlifedata.com/resource/pubmed/id/12782589

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
11
pubmed:dateCreated
2003-6-3
pubmed:abstractText
Although they are considered as antigen-presenting cells, the role of antigen-unspecific B lymphocytes in antigen presentation and T-lymphocyte stimulation remains controversial. In this paper, we tested the capacity of normal human peripheral activated B cells to stimulate T cells using melanoma antigens or melanoma cell lysates. B lymphocytes activated through CD40 ligation and then pulsed with tumor antigens efficiently processed and presented MHC class II-restricted peptides to specific CD4(+) T-cell clones. This suggests that CD40-activated B cells have the functional and molecular competence to present MHC class II epitopes when pulsed with exogenous antigens, thereby making them a relevant source of antigen-presenting cells to generate T cells. To test this hypothesis, CD40-activated B cells were pulsed with a lysate prepared from melanoma cells and used to stimulate peripheral autologous T cells. Interestingly, T cells specific to melanoma antigens were generated. Additional analysis of these T-cell clones revealed that they recognized MHC class II-restricted epitopes from tyrosinase, a known melanoma tumor antigen. The efficient antigen presentation by antigen-unspecific activated B cells was correlated with a down-regulation in the expression of HLA-DO, a B cell-specific protein known to interfere with HLA-DM function. Because HLA-DM is important in MHC class II peptide loading, the observed decrease in HLA-DO may partially explain the enhanced antigen presentation after B-cell activation. Results globally suggest that when they are properly activated, antigen-unspecific B-lymphocytes can present exogenous antigens by MHC class II molecules and stimulate peripheral antigen-specific T cells. Antigen presentation by activated B cells could be exploited for immunotherapy by allowing the in vitro generation of T cells specific against antigens expressed by tumors or viruses.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0008-5472
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
63
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2836-43
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
CD40-stimulated B lymphocytes pulsed with tumor antigens are effective antigen-presenting cells that can generate specific T cells.
pubmed:affiliation
National Cancer Institute, NIH, Bethesda, Maryland 20892, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't