M108

We previously reported that the monoclonal antibody M108 recognized a 40 kDa protein both in the nucleus and the cytoplasm. This nuclear 40 kDa antigen was located in the nuclear envelope in interphase cells and in the perichromosomal region during mitosis. Now, we have analyzed this nuclear 40 kDa protein (p40) further, through morphological and biochemical approaches. At the beginning of mitosis, the perinuclear p40 detached from the nuclear envelope and moved to surround the condensing chromatin, while in the late stage of mitosis, the perichromosomal p40 moved back to the reassembled nuclear envelope. Most of the perichromo-somal p40 on the metaphase chromosome was solubilized only by DNase I treatment, not by either high salt or detergent treatment. On the other hand, the perinuclear p40 was not solubilized by DNase1 alone, or high salt detergent alone. Sequential treatments with DNase I and high salt detergent were required to extract p40 in interphase nuclei. These results suggest that p40 was associated both with the nuclear envelope and chro-matin DNA in interphase nuclei, while it bound only to chromatin DNA in mitosis.

Monocytes have been demonstrated to play an important role in acute serum sickness (AcSS) nephritis. Because accumulation of monocytes within the glomeruli could be the result of local lymphokine production, we studied migration inhibition factor (MIF) activity in supernatants from glomerular cultures, analyzed its temporal relationship with monocyte and lymphocyte accumulation, and tested the effect of anti-T lymphocyte monoclonal antibody on local MIF production. AcSS was induced in 12 rabbits, and one additional rabbit had antigen elimination without proteinuria. Single nephrectomy was performed at the time of antigen elimination in all animals; the remaining kidney was removed four days (4 rabbits) or 14 days afterwards (5 rabbits). In glomerular cross sections (gcs), lymphocytes were identified using monoclonal antibody M108, and monocytes by nonspecific esterase stain (ES). MIF activity was determined in supernatants of cultures of isolated glomeruli by the agarose microdroplet method. Peak of MIF activity (84.3 +/- 2.6%, SEM) was observed the first day of proteinuria in association with peak of lymphocyte infiltration (1.15 +/- 0.1 lymphocytes/gcs) and monocyte infiltration (2.4 +/- 0.3 mean ES score/gcs). MIF activity diminished by day 4 (66.0 +/- 6.3%) and reached control levels by day 14 (12.8 +/- 3.2%). There was a significant correlation between lymphocyte infiltration and MIF activity (r = 0.776, P less than 0.0001) as well as between MIF activity and monocyte accumulation (r = 0.858, P less than 0.0001). In five additional rabbits with AcSS, glomeruli were isolated, treated successively with M108 and normal rabbit serum, and supernatants harvested from 24-hour cultures were tested for MIF activity.(ABSTRACT TRUNCATED AT 250 WORDS)