Engagement of the T cell receptor molecules with MHC-antigen complexes presented by B cells ascertains antigen specificity in T cell-dependent help. Ligation of MHC molecules on the surface of B cells, however, has not only been implicated in antigen-specific T-B cell interaction, but has also been linked to the induction of B cell apoptosis. To examine the role of T helper cells in either induction of immunoglobulin synthesis or B cell apoptotic death, we have facilitated T cell receptor-MHC interaction through a bacterial superantigen. CD4+ T cell clones could be categorized into two clearly distinct subsets based upon their ability to promote B cell help in the presence of superantigen. One subset of T cell clones supported immunoglobulin synthesis, and thus functioned as effective helper cells. B cells interacting with the second subset of T cells did not differentiate into antibody-secreting cells, but underwent apoptosis. Both types of helper cells were able to provide contact help after anti-CD3 stimulation. Induction of apoptosis was a dominant phenomenon; the addition of the superantigen suppressed immunoglobulin production in B cells activated by anti-CD3-stimulated helper T cells, indicating that the T cells delivered an apoptotic signal to the B cell. T cell clones providing effective MHC restrictive B cell help could be distinguished from T cells facilitating B cell apoptosis based on their lymphokine secretion profile. Induction of B cell apoptosis was a feature of T cells with a TH0 lymphokine pattern. Promotion of MHC-restricted B cell help was associated with a TH2 lymphokine profile. TH1-derived cytokines alone could not substitute for apoptosis-inducing T cells.
X He, W Zhong, J J Goronzy, C M Weyand
Usage data is cumulative from September 2023 through September 2024.
Usage | JCI | PMC |
---|---|---|
Text version | 148 | 0 |
87 | 14 | |
Figure | 0 | 1 |
Scanned page | 229 | 3 |
Citation downloads | 28 | 0 |
Totals | 492 | 18 |
Total Views | 510 |
Usage information is collected from two different sources: this site (JCI) and Pubmed Central (PMC). JCI information (compiled daily) shows human readership based on methods we employ to screen out robotic usage. PMC information (aggregated monthly) is also similarly screened of robotic usage.
Various methods are used to distinguish robotic usage. For example, Google automatically scans articles to add to its search index and identifies itself as robotic; other services might not clearly identify themselves as robotic, or they are new or unknown as robotic. Because this activity can be misinterpreted as human readership, data may be re-processed periodically to reflect an improved understanding of robotic activity. Because of these factors, readers should consider usage information illustrative but subject to change.