Immunotherapeutic effect of allogeneic tumor cells on the growth of autochthonous 3-methylcholanthrene-induced sarcomas in rats

The tumor-inhibitory effect of injections of allogeneic tumor cells was observed. Established autochthonous sarcomas induced in the subcutaneous tissue of rats by 3-methylcholanthrene (MCA) were treated with immunization by using allogeneic Hirosaki sarcoma cells. When MCA-induced sarcomas grew to approximately 1 cm in mean diameter, Hirosaki sarcoma cells were inoculated into various tissues of primary tumor-bearing rats. Immunizing procedures consisted of intraperitoneal and subcutaneous injections in one experimental group, and of intradermal and intraperitoneal injections in another. Significantly inhibitory effect on the growth of autochthonous sarcomas was observed in the initial stage up to 2 cm in diameter as compared with that of control sarcomas. No significant inhibition was seen in the course of the growth of sarcomas larger than 2 cm in diameter. This results may indicate that immunotherapy by using allogeneic tumor cells should be considered to be valuable for the treatment of human cancer.

Histochemical demonstration of enzyme activities in plastic and paraffin embedded tissue sections

Histochemical staining for enzymes is usually performed on frozen sections. This report lists the longer incubation times required to demonstrate esterase, acid phosphatase, beta-galactosidase, and cytochrome oxidase in plastic embedded and ruotine paraffin embedded tissues. The sections embedded in plastic, i.e. water soluble methacrylate (Polyscience's JB-4) and cut at 2 micrometers, were far superior to frozen sections and paraffin embedded sections both in tissue detail and in the localization of the histochemical reaction product.

Activation of alveolar macrophages exposed to lavage-procured immunoglobulin G obtained from normal rabbit lungs

Pulmonary washings from rabbits were freed of cells and added to the monolayers of homologous alveolar macrophages (AM). At 1 h after incubation with the pulmonary washings, many more cells adhered to glass, spread out, and showed enhanced Nitro Blue Tetrazolium reduction. The maximal effect of the pulmonary washings on AM activation was obtained 12 h after incubation. The AM activated by the pulmonary washings showed a higher capacity to inhibit the growth of intracellular BCG, and that capacity was correlated with the intensity of Nitro Blue Tetrazolium reduction by the AM. Gel filtration of the pulmonary washings through Sepharose 4B yielded five fractions. The factor that activated the AM functions was in fraction 4. When the immunoglobulin G in the fraction was removed by an immunoadsorbent column, AM activity was abolished. The effect of the immunoglobulin G was dose dependent, and minimal responses to 10(6) cells per ml were obtained at a protein concentration of 20 mug/ml. Lymphokines had no effect on AM activation with respect to the morphological alterations and Nitro Blue Tetrazolium reduction during the 24-h observation time. In summary, AM from normal rabbits were soon activated markedly by lavage-procured immunoglobulin G, but not by lymphokines.

Different effects of phytohemagglutinin-activated lymphocytes and their culture supernatants on macrophage function

When rabbit peritoneal exudate cells were incubated for 24 and 48 h with phytohemagglutinin-activated lymphocytes or their culture supernatants, two times as many cells remained adherent to culture slides as in the controls. More spreading cells were found among the adherent cells in the stimulated cultures. Eighty percent of spreading cells that were induced by supernatants were negative or faintly positive for beta-galactosidase. On the other hand, half of the spreading cells induced by activated lymphocytes were positive (1+ to 4+) for beta-lymphocytes and their supernatants. Under similar conditions, unstimulated peritoneal cells showed less marked activation. These findings show that macrophages can appear morphologically activated and yet not be enzymatically activated by lymphokines. Possible mechanisms of direct interaction of activated lymphocytes and macrophages are discussed.

Effect of immunization with an allogeneic tumor on the growth of primary methylcholanthrene-induced sarcomas in rats

Making use of common antigenicity among allogeneic tumors, the immunotherapy against primary 3-methylcholanthrene(MCA)-induced sarcomas in rats was attempted. At the time when MCA-induced sarcomas reached approximately 1 cm in diameter, allogeneic Usubuchi sarcoma cells were injected 5 times into the subcutaneous tissue of rats. In most cases, inhibitory effect on the growth of the tumor was observed in the early period, but none of 29 cases treated resulted in final regression. Twenty-nine non-treated cases showed uniformly progressive growth from the beginning. This result seems to indicate the possibility of using allogeneic tumor(s) for the immunotherapy against human cancer.