GRANULOCYTE MACROPHAGE COLONY-STIMULATING FACTOR ENHANCES MACROPHAGE ACCESSORY FUNCTION IN CON-A-STIMULATED T-CELL PROLIFERATION

Granulocyte-macrophage colony-stimulating factor (GM-CSF) has been reported to augment various macrophage (Mφ) functions, including antigen presentation in the antibody-producing response. We investigated the augmentative effect of GM-CSF on Mφ A-cell activity in concanavalin A-stimulated T-cell proliferation. Pretreatment with GM-CSF of peritoneal Mφ enhanced the T-cell proliferative response. This effect of GM-CSF was dose dependent and GM-CSF supplementation was needed at the beginning of Mφ culture. We observed that GM-CSF induced Mφ spreading and firm attachment accompanied with enlargement of the cytoplasm, but could not induce de novo expression of Ia antigen. GM-CSF treatment enabled Mφ to produce more interleukin (IL)-1 and IL-6 upon stimulation with lipopolysaccharides or polyinosinic-polycytidylic acid, but was unable to stimulate Mφ directly. This was confirmed by Northern blot analysis. These results indicate that GM-CSF augments Mφ A-cell activity through the enhancement of the capacity of Mφ to produce IL-1 and IL-6. © 1990.