INHIBITION OF MONOCYTE COMPLEMENT RECEPTOR ENHANCEMENT BY LOW-MOLECULAR WEIGHT MATERIAL FROM HUMAN-LUNG CANCERS

  • 1 January 1981
    • journal article
    • research article
    • Vol. 43  (3) , 540-548
Abstract
The effect of dialysates from lung cancer homogenates to alter complement (C3b [complement component 3b]) receptor expression per se and to inhibit leucoattractant-induced complement rosette enhancement on monocytes from healthy individuals was studied. Enhancement and enhancement-inhibition by tumor extracts were compared with material derived from normal lung excised some distance from the tumor. There was no significant difference between tumor homogenate (TH) and normal lung homogenate (NLH) in terms of enhancement of complement rosettes per se. TH produced a dose- and time-dependent inhibition of leucoattractant-induced enhancement of C3b rosettes which was significantly different from that obtained with NLH. This enhancement-inhibition was observed with 4 undifferentiated, 4 squamous and 3 adenocarcinomas of the lung. The degree of enhancement-inhibition was not related to the type of tumor or varying accompanying histological features such as necrosis and the degree of inflammatory cell infiltration. Following gel filtration on Sephadex G-50 each type of cancer gave a major inhibitory activity peak which eluted with molecules having an apparent molecular size of approximately 3000 daltons. A 2nd larger peak (8000-10,000 daltons) was also detectable with extracts from the undifferentiated and adenocarcinomas. Apparently, anti-macrophage/monocyte principles are elaborated from certain tumor types.