Document Detail

Helper T-cell subsets: phenotype, function and the role of lymphokines in regulating their development.
MedLine Citation:
PMID:  1684776     Owner:  NLM     Status:  MEDLINE    
We have concentrated here on the lymphokines which might serve to regulate the different pathways of precursor development. We suggest that, as a result of antigenic stimulation, specific precursor cells both proliferate and become committed to develop into either an effector cell, a memory cell or an anergized cell. Anergy has not been dealt with in this review, but it is likely to be one of the options available. The development of an effector population takes 4-7 d (quite analogous to the time it takes for CTLp to become CTL and for resting B to become Ab-forming cells). The effector populations are large, generally IL-2R-positive cells. These cells have upregulated many adhesion molecule systems [e.g., Pgp-1, LFA-1 and ICAM-1 (Swain unpublished)], but downregulated the Mel-14 homing receptor. Effectors are ready to respond to APC such as specific B cells with a rapid synthesis and secretion of lymphokines. The effector population is then quickly downregulated, both by the turn off of lymphokine synthesis/secretion and possibly by its own suicide. This kind of pattern makes teleological sense since the cells making such high titers of lymphokines could have many potent pleitropic effects. It also seems to be the strategy employed in the generation of other terminally differentiated effectors (such as CTL and plasma cells). The requirement for restimulation and the requirement for direct and perhaps prolonged contact between the helper effector and the APC-B cell can be expected to help ensure that these lymphokines are localized (reviewed in Swain & Dutton 1987, Swain & Croft 1990) and effectively delivered to specific responding cells. We postulate that at the same time, or perhaps subsequent to this, another set of signals drives precursors to generate prememory cells. Our studies suggest these emerging memory cells may be phenotypically unique and we postulate that they are specialized to become a "long-lived" population of memory cells that will persist indefinitely as a protective population of increased frequency for the antigen encountered and which is also able to respond more rapidly and effectively. The greater effectiveness of the memory response would thus be due to dramatically increased frequency, to characteristic and stable changes in adhesion molecule expression and to the fact that, in addition to IL-2, resting memory cells also secrete at least low titers of IL-3, IL-4, IFN-gamma and other lymphokines upon initial restimulation.(ABSTRACT TRUNCATED AT 400 WORDS)
S L Swain; L M Bradley; M Croft; S Tonkonogy; G Atkins; A D Weinberg; D D Duncan; S M Hedrick; R W Dutton; G Huston
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Publication Detail:
Type:  Journal Article; Review    
Journal Detail:
Title:  Immunological reviews     Volume:  123     ISSN:  0105-2896     ISO Abbreviation:  Immunol. Rev.     Publication Date:  1991 Oct 
Date Detail:
Created Date:  1992-02-13     Completed Date:  1992-02-13     Revised Date:  2005-11-16    
Medline Journal Info:
Nlm Unique ID:  7702118     Medline TA:  Immunol Rev     Country:  DENMARK    
Other Details:
Languages:  eng     Pagination:  115-44     Citation Subset:  IM    
Department of Biology, University of California, San Diego, La Jolla 92093-0063.
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MeSH Terms
CD4-Positive T-Lymphocytes / immunology
Lymphocyte Activation
Lymphokines / immunology*
T-Lymphocyte Subsets / immunology
T-Lymphocytes, Helper-Inducer / immunology*
Reg. No./Substance:

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