BASIC SURFACE-PROPERTIES OF MONONUCLEAR-CELLS FROM DIDELPHIS-MARSUPIALIS

The electrostatic surface charge and surface tension of mononuclear ce lls/monocytes obtained from young and adult marsupials (Didelphis mars upialis) were investigated by using cationized ferritin and colloidal iron hydroxyde, whole cell electrophoresis, and measurements of contac t angles. Anionic sites were found distributed throughout the entire i nvestigated cell surfaces. The results revealed that the anionic chara cter of the cells is given by electrostatic charges corresponding to - 18.8 mV (cells from young animals) and -29.3 mV (cells from adult anim als). The surface electrostatic charge decreased from 10 to 65.2% afte r treatment of the cells with each one of trypsin, neuraminidase and p hospholipase C. The hydrophobic nature of the mononuclear cell surface s studied by using the contact angle method revealed that both young a nd adult cells possess cell surfaces of high hidrofilicity since the a ngles formed with drops of saline water were 42.5 degrees and 40.8 deg rees, respectively. Treatment of the cells with trypsin or neuraminida se rendered their surfaces more hydrophobic, suggesting that sialic ac id-containing glycoproteins are responsible for most of the hydrophili city observed in the mononuclear cell surfaces from D. marsupialis.