Cross-reactive cellular and humoral immunity to carcinogen-induced chicken fibrosarcomas. II. Effect of prior immunization with transplantable tumors on primary tumor incidence.

Primary carcinogen-induced (7,12-dimethyl-benz[a]anthracene; DMBA) tumor-bearing SC chickens (B2/B2) frequently showed antibodies in their sera which reacted with cells from their autochthonous tumors, chicken embryo fibroblasts (CEF), tumor cells from some transplantable tumor lines, and from approximately 10% of other primary tumors. Similar results were obtained by ELISA on glutaraldehyde-fixed cells and by immunofluorescence on viable cells. The serum antibody reactivity could be removed by absorption with CEF but not with non-cross-reacting primary tumor cells or a variety of normal tissues. Although sera from normal chickens never showed significant reactivity, a high percentage of sera from chickens that had been injected with DMBA but failed to develop detectable tumors showed antibody activity to a transplantable DMBA-induced tumor and to CEF. On the basis of previously established cross-reactivity patterns in protective immunity to transplantable carcinogen-induced fibrosarcomas, attempts were made to protect against chemical carcinogenesis by prior immunization with selected DMBA-induced transplantable tumors. Tumor-immune chickens showed a significant decrease in the development of tumors during the first 3 mo after injection of DMBA (p = 0.001) or methylcholanthrene (p = 0.033) when compared to controls. This resistance to tumor induction in immune chickens was correlated to the degree of tumor immunity to the immunizing tumor present 1 mo after carcinogen injection (p = 0.046). There was, however, no detectable difference in the incidence of tumors arising later than 3 mo after carcinogen injection. The reduction in tumor incidence in immune as compared to control chickens at 5 mo was therefore less striking than the reduction seen at 3 mo. Immunization with CEF and adjuvants or with adjuvants alone afforded no protection to tumor induction.

Defective bursa regeneration after irradiation of young thymectomized chickens.

The ability of the bursa of Fabricius to regenerate after gamma-irradiation and bone marrow reconstitution was examined in chickens thymectomized (TX) immediately after hatching. Irradiation (2 X 500 R) 3 weeks after hatching was followed by impaired bursa regeneration, as judged both by bursa/body weight ratios and by bursa follicle development 3-6 weeks later in TX as compared to control birds. Germinal center formation in the spleen was deficient, and immune responses to sheep erythrocytes (SRBC) and B. abortus (BA) were moderately reduced in the TX as compared to control birds irradiated at 3 weeks but not in TX birds irradiated at 5 weeks of age.

Derivation of transplantable 7,12-dimethylbenz[a]anthracene-induced chicken fibrosarcoma lines: differences in metastasizing properties and organ specificity.

Several transplantable 7,12-dimethylbenz[a]anthracene-induced SC chicken fibrosarcoma (CHCT-NYU) lines were studied for their ability to grow in internal organs after iv injection (artificial metastases) into 1- to 3-week-old chickens. Some tumor lines were recently derived, whereas others were studied after many serial subcutaneous transplantations. STriking similarities as well as differences were found between tumor lines' ability to grow in various organs. Artificial metastases were seen primarily in the stomach, pancreas, lungs, heart, and muscle, and occasionally also in the kidneys and in the liver. Agammaglobulinemic recipients showed more extensive organ involvement than normal recipients of the same age. Whole-body gamma-irradation also enhanced the incidence of artificial metastases, particularly in lungs. Antibody from the serum of a primary tumor-bearing host reduced the growth of the corresponding tumor in many organs. The metastatic pattern of line CHCT-NYU4 was a relatively stable property, since there was little difference in the internal localization of these tumor cells studied before and after 15 serial subcutaneous transplants. However, intravenous transplantation of tumor cells from line CHCT-NYU4 taken from the liver, lungs, and pancreas of a single recipient established sublines with changes in organ specificity. After a few such serial transplants of liver-derived tumor, a line was derived that grew virtually in the liver alone. A subline with preference for growth in lungs was also obtained, but its ability to grow in the pancreas persisted. A pancreas-derived tumor line also grew in the liver and lungs. Subcutaneous transplants of tissue fragments of the lung-derived tumor line caused the appearance of spontaneous metastases in lungs. The incidence of spontaneous metastases with the lung-derived line was much greater than that with the liver-derived line or with the original CHCT-NYU4 line.

gamma-Irradiation-induced mortality: protective effect of protease inhibitors in chickens and mice.

Chickens (Gallus domesticus) were protected from the acute gamma-irradiation-induced mortality (within 24 hours) by the proteolytic enzyme inhibitors, soy-bean trypsin inhibitor (SBTI), lima bean inhibitor (LBTI), antipain, alpha-N-benzoyl-L-arginine ethyl ester HCl (BAEE), trasylol, and leupeptin. Several other enzyme inhibitors, p-tosyl-L-arginine methyl ester HCl (TAME), alpha-tosyl-lysyl-chloromethyl ketone HCl (TLCK) and epsilon-amino caproic acid (EACA), did not protect. EACA even increased the mortality caused by gamma-irradiation. The pattern of protective enzyme inhibitors suggests involvement of a kallikrein-like enzyme. SBTI and antipain also protected against low range lethal gamma-irradiation exposures, 690 R in BALB/c and 880 R in SJL/J mice. It is suggested that enhanced vascular permeability, which in chickens is known to be the cause of the irradiation mortality during the first 24 hours, may also contribute to the mortality in mice during the first week after irradiation.