Linked Life Data

2952281

Source:http://linkedlifedata.com/resource/pubmed/id/2952281

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1987-6-5
pubmed:abstractText
Myoglobin-specific, Iad-restricted cloned helper T cells and T hybridomas were found to directly kill Iad-bearing, myoglobin-pulsed B lymphoma targets and could also kill bystander targets, but only in the presence of antigen-pulsed antigen presenting cells (APC). The induction of the killing requires recognition of processed antigen in the context of class II major histocompatibility complex (MHC) molecules. Despite the specificity of induction, the bystander killing suggests a nonspecific lytic mechanism. The direct killing can be inhibited only by cold specific targets, whereas the bystander killing can be blocked by both specific and nonspecific targets. The cold target inhibition seems to be due to interference with effector-to-target contact or proximity rather than due to high-dose suppression of T-cell activation. Experiments using T-cell supernatants or cyclosporin A suggested that the helper T cells kill targets by synthesizing short-range soluble factor(s) with nonspecific killing activity de novo during the effector phase, but only while antigen-specific signal transduction is occurring. The mechanism of cold target inhibition appears to be absorption or consumption of a short-acting cytotoxic lymphokine by cells which must be able to interact closely with the effector cell. Normal spleen B cells, despite their capability for activating the helper T cells, cannot inhibit specific killing or be killed by helper T cells, even after lipopolysaccharide stimulation. Thus, although killing by helper T cells may play a negative feedback role in the normal immune response, our data raise the possibility that the helper T-cell-mediated killing may contribute to the immune surveillance against malignancy by virtue of the preferential killing of tumor cells either directly or indirectly.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0008-8749
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
105
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
301-16
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1987
pubmed:articleTitle
Cloned protein antigen-specific, Ia-restricted T cells with both helper and cytolytic activities: mechanisms of activation and killing.
pubmed:publicationType
Journal Article, Comparative Study