Reports by a number of investigators have described the thymus-derived (T)-cell dependence of immunoglobulin synthesis by pokeweed mitogen (PWM) stimulated human peripheral blood bone marrow-derived (B) cells. Because of the cooperative nature of this in vitro system, it was chosen for examination of the differential effects of low density lipoprotein inhibitor (LDL-In) on B- and T-cell functions. Supernates from 7-d cultures that contained either peripheral blood mononuclear cells (PBM) or combinations of isolated lymphocyte populations were assayed for immunoglobulin (Ig)G by competitive inhibition radio-immunoassay. LDL-In suppression of whole PBM IgG synthesis occurred at 5-20 μg protein/ml and was independent of PWM concentration. Maximal suppression required preincubation of cells with LDL-In before stimulation. Suppression was also observed when B cells alone were exposed for 24 h to LDL-In before PWM stimulation; these suppressed B cells were not rescued by normal T cells. Exposure of T cells alone to low doses of LDL-In for 24 h augmented, but high doses suppressed, IgG synthesis, suggesting a differential effect on T-helper vs T-suppressor cell populations. Independent LDL-In exposure of T-helper or T-suppressor cell enriched populations, separated by rosetting with IgG- or IgM-coated ox erythrocytes, identified the T-suppressor cell populations as the most sensitive of the lymphocyte populations tested. The sensitivities of lymphocyte subpopulations to LDL-In, relative to PBM, were 2.8, 1.2, and 0.3 for the T-suppressor cells, B cells and T-helper cells, respectively. Thus, both B and T lymphocytes are sensitive to and can be regulated by LDL-In. In addition, the biologic activity observed when unseparated PBM are exposed to LDL-In appears to represent a composite of the sensitivity of each of the lymphocyte subpopulations.
Linda K. Curtiss, Thomas S. Edgington
Usage data is cumulative from July 2023 through July 2024.
Usage | JCI | PMC |
---|---|---|
Text version | 125 | 0 |
66 | 21 | |
Scanned page | 173 | 4 |
Citation downloads | 18 | 0 |
Totals | 382 | 25 |
Total Views | 407 |
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.