Regulation of corneal collagenase production: stimulation of serially passaged stromal cells by blood mononuclear cells.

After three or more passages, stromal cell outgrowths from explants of normal rabbit corneas and from corneas previously burned with alkali did not produce collagenase until they were stimulated by the addition of rabbit blood-derived mononuclear cells or media conditioned by them. Normal stromal cells required stimulation by lymphocytes or their products from alkali-burned animals, whereas those from alkali-burned corneas were stimulated by lymphocytes from either normal or alkali-burned rabbits.