Divergent effects of silica on lymphocyte proliferation and immunoglobulin production.
Silicosis is an interstitial lung disorder that is frequently associated with hypergammaglobulinemia and increased numbers of lymphocytes at sites of disease. To determine the effect of silica on the generation of immunoglobulin-secreting cells, mononuclear cells were stimulated with antigens or mitogens and placed into 1) high-density cultures (2.5 X 10(6) cells/ml) that were not exposed to silica, in which pokeweed mitogen (PWM)-induced generation of immunoglobulin-secreting cells was suppressed by the presence of monocytes; or 2) low-density cultures (0.5 X 10(6) cells/ml) that were not exposed to silica, in which PWM-induced generation of immunoglobulin-secreting cells was not suppressed. Silica added to PWM-stimulated high-density cultures significantly increased the numbers of immunoglobulin-secreting cells. Silica also significantly increased the numbers of immunoglobulin-secreting cells in high-density cultures stimulated with purified protein derivative and tetanus toxoid and augmented the proliferation of phytohemagglutinin-stimulated mononuclear cells (P less than 0.05). In contrast to high-density cultures, silica added with PWM to low-density cultures reduced the numbers of immunoglobulin-secreting cells. These studies suggest that silica can have potent regulatory effects on various cellular immune processes that are relevant to the lung.
Moseley
P L
PL
Department of Internal Medicine, Veterans Administration Hospital, Iowa City, Iowa.
Monick
M
M
Hunninghake
G W
GW
D002470:Cell Survival / Q000187:drug effects; D015232:Dinoprostone; D006801:Humans; D007136:Immunoglobulins / Q000096:biosynthesis*; D008213:Lymphocyte Activation / Q000187:drug effects*; D008214:Lymphocytes / Q000187:drug effects / Q000276:immunology*; D011043:Pokeweed Mitogens / Q000494:pharmacology; D011458:Prostaglandins E / Q000096:biosynthesis; D012822:Silicon Dioxide / Q000494:pharmacology*; D013745:Tetanus Toxoid / Q000494:pharmacology
D007136:Immunoglobulins; D011043:Pokeweed Mitogens; D011458:Prostaglandins E; D013745:Tetanus Toxoid; D012822:Silicon Dioxide; D015232:Dinoprostone