Search

Tumor antigen (TA) associated with the canine transmissible venereal sarcoma (CTVS) was detected in the sera of dogs bearing the tumor. Rabbit antisera specific for tumor antigen and 3 M KCl extracts of CTVS cells were used in both a competitive enzyme-linked immunosorbent assay (ELISA) and antigen-capture ELISA to quantify levels of circulating TA. In a study of 29 dogs bearing the transplanted CTVS, levels of circulating TA correlated positively with tumor volume. In a longitudinal study of four dogs receiving a transplant of 10(8) viable CTVS cells, circulating CTVS antigen was detected transiently 2 days after transplantation, while persistent levels of TA associated with increasing tumor volume were demonstrable 19-34 days after transplantation. In three of four tumor-bearing dogs, levels of serum TA correlated inversely with values obtained with peripheral blood leukocytes in the leukocyte adherence inhibition (LAI) assay; elevated levels of circulating TA found in dogs with large (greater than 7 cm3) tumors were associated with decreased LAI reactivity of peripheral blood leukocytes. TA could not be detected in sera 48-72 h after surgical removal of CTVS whereas LAI reactivity of peripheral blood leukocytes to CTVS antigen rebounded 1-3 weeks following tumor excision. Results of this study support the use of the competitive ELISA and LAI techniques in assessing levels of circulating tumor antigen, tumor burden and tumor-specific immunity.

The structure of canine transmissible venereal sarcoma (CTVS) has been examined from 14 to 71 days after implantation. During early growth, the tumour appears to be composed primarily of loosely arranged, round cells and a few fibroblast-like cells. As the tumour mass increases, the round cells become tightly packed with highly interdigitating plasma membranes. The number of irregularly shaped round cells and fibroblast-like cells increases with increasing tumour mass. Collagen and reticular fibres can be found in early tumours, frequently in association with the round cells, and in regions devoid of fibroblast-like cells. During tumour regression, cellular degradation is evident in fibroblast-like and irregularly shaped cells as well as round cells. The data suggest that transformation may occur in the course of tumour growth, causing morphological change from round to fibroblast-like cells, and that CTVS is an undifferentiated round-cell sarcoma capable of differentiation in a fibroblastic direction. Also present, primarily in tumour cells from newborn dogs, are cytoplasmic lamellar arrays and crystalline virus-like structures, both previously described in other forms of tumor cells. Images Figs. 1-3 Fig. 4 Figs. 5-8 Fig. 9 Figs. 10-12 Figs. 13-14

Electron microscopic study of the canine transmissible venereal sarcoma (N = 26) at different stages of growth showed that tumors in a progressive phase of growth (N = 12) were comprised mostly of large, round cells with prominent nuclei and nucleoli, a few spindle-shaped cells and collagen fibers, focal areas of necrosis, and lymphocyte infiltrates. Regressing tumors (N = 9) had the fewest viable round cells, greater numbers of infiltrating leukocytes, and were comprised almost entirely of connective tissue (collagen bundles) in the latest stages of regression. The infiltrating leukocytes consisted primarily of lymphocytes, some eosinophils, and neutrophils, but very few macrophages. Round-cell nuclei contained numerous perichromatin and interchromatin granules. Their cytoplasm often had annulate lamellae complexes and large deposits of glycogen. Loosely packed tumor cells had extensive proliferation and elongation of cytoplasmic extensions (filopodia). Evidence for cell-mediated tumor cell lysis was demonstrated by degenerative changes in tumor cells which were closely apposed to lymphocytes. Spindle-shaped cells in regressing tumors had intravacuolar collagen fragments, suggesting a possible degradative capacity by these cells. Canine transmissible venereal sarcoma, also called transmissible venereal tumor of dog and Sticker's sar- coma, is a naturally occumng round cell neoplasm of the genital tracts of male and female dogs. Although normally transmitted through coitus, tumors may be induced experimentally by inoculation of viable tumor cells into normal, non-preconditioned dogs. In either neonatal or immunosuppressed dogs, this sarcoma usu- ally grows vigorously and meta~tasizes,~.~~ but the his

We examined the regulation of leukocyte glass adherence and tube leukocyte adherence inhibition (LAI) reactivity by serum factors in dogs with regressing or progressing canine transmissible venereal sarcomas (CTVS). Both regressor and progressor peripheral blood leukocytes (PBL), draining and non-draining lymph node cells (LNC), and splenic leukocytes were significantly responsive to CTVS antigen extract in tube LAI. In contrast, a significant decrease in basal glass adherence of progressor PBL, draining and non-draining LNC, and splenic leukocytes was observed. Normal glass adherence was restored to progressor leukocytes by extensive washing with warm serum-free media, while significant tube LAI responsiveness to CTVS antigen extract was maintained. Preincubation of regressor PBL and LNC with progressor sera in two-stage tube LAI decreased the basal glass adherence of treated leukocytes. This effect of progressor sera was heat labile, a characteristic of CTVS antigen. Collectively, these findings suggest that progressor leukocytes and progressor sera treated regressor leukocytes were activated by interaction with serum CTVS antigen and thus behaved in tube LAI as stimulated cells, even in the absence of CTVS antigen. Regressor but not progressor sera were shown to contain anti-CTVS IgG with specific arming activity for normal dog PBL, but not LNC in two-stage tube LAI. The nonadherent response of peripheral blood neutrophils in two-stage tube LAI was proportional to the concentration of arming IgG, whereas no change was observed in glass adherence of PBL. The results of this study define the role of progressor and regressor serum factors in the mechanism of tube LAI and demonstrate a relationship between leukocyte glass adherence and the clinical course of CTVS. These findings show that tube LAI is a simple and reproducible measure of active factors in the immune response to a tumor.

Intraarticular inoculation of Mycoplasma bovis into the joints of six-week-old calves caused severe arthritis in five inoculates and mild arthritis in a sixth. Intraarticular inoculation of killed M. bovis did not cause arthritis.Arthritic calves had fever, joint swelling, lameness, neutrophilia, and intercurrent pneumonia from which M. bovis could not be recovered.Gross lesions were massive fibrinosuppurative synovitis and tenosynovitis, erosion of cartilage, and its replacement by polypoid granulation tissue. Histologic lesions were extensive ulceration of synovial membranes, leukocytic infiltration of the suhsynovium, congestion, hyperemia, and thrombosis of the subsynovial vessels. Cartilage erosion was accompanied by chronic osteomyelitis and formation of pannus tissue.The presence of thrombi and platelet aggregates suggests that the inflammatory process in the synovium may arise from the interaction of M. bovis with the vasculature and the coagulation process of the host.