Haruhisa Hayashi

Analysis of electrophoretic mobility histograms of mouse splenocytes and thymocytes during tumor growth and after combined chemotherapy and immunotherapy.

Changes in electrophoretic mobility histograms of splenocytes and thymocytes were studied in plasmacytoma X5563-bearing mice as an indicator of response to treatment with mitomycin C (MMC) alone or combined with the immunomodulator Krestin (PSK). Tumor growth was inhibited by 80-90% in the MMC-treated and was further inhibited in the MMC and PSK-treated group. Electrophoretic mobility histograms of splenocytes were used to determine the fraction of cells having intermediate mobility between high mobility (T cells) and low mobility (B cells). This fraction of intermediate-mobility cells increased in tumor-bearing mice, but a normal electrophoretic mobility pattern was obtained following successful antitumor treatment. In the electrophoretic mobility histogram of thymocytes, on the other hand, the low-mobility cells (cortical thymocytes) decreased in number during tumor growth and were further reduced in the MMC-treated group. This reduction was less in the MMC and PSK-treated group. These results suggest that combined therapy with MMC and PSK prevents damage of the host defence mechanism and allows more efficient antitumor treatment. Analysis of electrophoretic mobility histograms of splenocytes and thymocytes using a fully automated cell electrophoretic instrument makes possible the rapid evaluation of the immunological effects of drug therapy of tumor-bearing mice.

Tumor Growth-Promoting Effect of Immunosuppressive Substance in Mice

The effect of immunosuppressive (IS) substance obtained from cancerous ascitic fluid on tumor growth and host immunity in plasmacytoma X5563-bearing C3H/He mice is described. IS substance given in three injections, before and after tumor inoculation caused: (a) enhanced tumor growth, (b) marked reduction in survival times, (c) inhibition on Con-A response of spleen cells. Depressed natural killer (NK) activity was observed in normal and tumor-bearing mice treated with IS substance. The data presented here suggest that IS substance suppresses both humoral and cellular immunoresponsiveness and tumor cells evade immune surveillance or immunologically mediated removal.

Determination of an immunosuppressive substance in serum by latex particle electrophoresis

The level of immunosuppressive substance (IS), which increases in the serum of patients with cancer, was determined by an assay based on particle electrophoresis. Polystyrene latex particles (PLP) were coated with IS, which was extracted from the ascitic fluid of patients with cancer. The IS was a glycoprotein with a molecular weight of about 52,000, and an isoelectric point in the range pH 2.7-3.3. When the IS on the surface of the PLP reacted with the anti-IS antibody, the mean electrophoretic mobility of the PLP changed from -3.16 to +0.21 micron.s-1.V-1.cm in the medium of pH 7.2 and ionic strength I = 0.0154. After preincubation of anti-IS antiserum and tested serum, the PLP coated with IS were added to this solution. It was incubated again and then the surface charge of the PLP was measured by an automatic cell-electrophoretic instrument. This method was used to determine the IS concentration in the serum of cancer patients and pregnant women. When compared to healthy controls, the serum IS level was significantly higher in patients with cancer, and lower in pregnant women. The assay based on latex-particle electrophoresis proved to be a sensitive and rapid method for determining the IS level in serum.