Colony formation by bone marrow cells after incubation with neuraminidase. II. Sensitivity of erythroid progenitor cells for burst promoting activity and erythropoietin and restoration of reduced spleen colony formation in mice pretreated with desialated erythrocyte membrane fragments
Ploemacher, R.E.; Brons, N.H.; de Vreede, E.; van Soest, P.L.
Experimental Hematology 9(2): 156-167
1981
ISSN/ISBN: 0301-472X PMID: 6113156 Document Number: 181872
Incubation of bone marrow cells (BMC) with neuraminidase (NA) reduces their ability to form colonies in the spleen of lethally irradiated mice. In vivo the largest reduction was observed in the erythrocytic colonies, whreas in vitro an inhibiting effect of NA incubation was observed on the plating efficiency of erythrocyte precursors (CFUE and day 7 BFUE). Masking the receptors for neuraminidase-treated cell surface determinants in the recipient's body by injection of desialated erythrocytes (NA-Ery) or erythrocyte membrane fragments (NA-Efr) largely restored the reduced colony formation of NA-BMC with respect to both the total number of spleen colonies and their type. Pretreatment of irradiated hosts with NA-Ery, but not with NA-Efr, led to a slight polycythemia as judged by the number of erythrocytic and undifferentiated colonies as well as by the surface colony diameter. The reduced erythrocytic colony formation of NA-BMC was considerably enhanced in anemic irradiated recipients (from 25-70% of respective controls). Under all experimental circumstances the erythrocytic colony formation of NA-BMC never exceeded that of normal BMC (N-BMC). In normal or anemic recipients whether or not treated with NA-Efr, the diameters of the spleen surface colonies in NA-BMC injected animals were smaller than in recipients of control-incubated BMC. In vitro experimentation indicated that the reduced plating efficiency of CFUE and BFUE following incubation could not be attributed to a decreased sensitivity to erythropoietin. Day 7 BFUE with deficient cell surface sialic acid residues had a decreased sensitivity to burst promoting activity. The desialated colony forming cells that give rise to erythrocytic colonies in vivo apparently have higher requirements for early regulatory factors than granulocytic precursor cells. In contrast to the normal postirradiation situation the level of these factors could be increased in recipients, which are bled subsequent to irradiation. Neuraminidase-treated CFU are evidently fully capable of exhibiting normal, although delayed, colony formation in vivo in animals with covered receptors for galactosyl residues.