Opposing changes in electrokinetic potential of spleen cells induced by factors from different tumour supernatants

Tumour supernatants were tested on normal spleen cells electrophoretic mobility. In the case of two tumours, characterized by a fast growth rate (RV2 and VFM1), supernatants produced an increase in the mean electrophoretic mobility. For the two other tumours, characterized by a slow growth rate (VMM2 and VMM1), supernatants produced a decrease in the mean electrophoretic mobility. Electrophoretic mobility analysis of mouse spleen cells showed that after treatment with RV2 tumour supernatant, the percentage of 'slow' cells decreased by about 20%. VMM2 supernatant produced an increase in 'slow' cells of about 20%. The effect of dialysed supernatants (with mol. wt cutoff 12,000) was different. VMM2 and VMM1 dialysed supernatants modify spleen cells mobility as VMM2 and VMM1 undialysed supernatants. RV2 and VFM1 dialysed supernatants induced a significant slowing in the mobility in regard to RV2 and VFM1 undialysed supernatants. RV2 and VMM2 tumour supernatants were fractionated into four fractions on Sephacryl S-300. Fraction II (mol. wt of about 400,000) from VMM2 supernatant was found to reduce significantly the spleen cells' mobility. In contrast, fraction IV (mol. wt less than 12,000) from RV2 supernatant increases significantly the mobility, and fraction IV (mol. wt less than 12,000) from VMM2 supernatant reduced the mobility significantly. These different charge changes in spleen cells after contact with supernatants from slow and fast growth rate tumours might influence the contact between tumour and lymphocytes.