Studies on FeSV induced sarcomata in sheep with particular reference to the regional lymphatic system

Abstract

Summary.-Inocula of cultured sheep cells that had been transformed with FeSV were injected into the legs of sheep so that the changes in the cellular and humoral composition of the efferent lymph from the regional node could be studied throughout the immune responses. The times at which immunoblasts and specific antibodies appeared in the lymph were similar to those recorded during responses to conventional antigens. The antibodies were mainly 7S, Gl immunoglobulins directed against virion antigens on the membranes of the transformed cells.Larger doses of transformed cells were injected into 12 sheep so that 4 of them developed locally invasive, poorly differentiated fibrosarcomata. Two tumours regressed spontaneously; 2 grew progressively and one of these gave rise to regional metastases. The progressive tumours were not infiltrated with host cells and grew in the presence of high titres of antibody. The tumours that regressed were infiltrated heavily with round cells and detectable antibody was low or absent.The flow and composition of peripheral lymph coming from the tumours showed that the failure of the host to control tumour growth could not be accounted for by a failure of the tumour capillaries to allow the normal transmigration of host cells and humoral factors.

Levels of adenosine deaminase in some experimental animal tumours and the possible therapeutic effect of the ADA inhibitor 2-deoxy-coformycin

“…The enzyme was present in nearly all the tumours examined but, unlike human leukaemic lymphoblasts, the rodent leukaemias and lymphomas did not have particularly high levels. However, high levels occurred in the rat plasma-cell tumour that secreted IgA, in all generations of the Hall et al, 1975;1969;(5) Bazin et al, 1972. tumour examined, irrespective of whether it had been grown in the peritoneal cavity or subcutaneously. Because of this it was selected for treatment with deoxy-coformycin.…”

“…Hall et al, 1975) 1I0 ml of distilled water was added and the mixture was teased and divided as finely as possible with scalpel blades and, where possible, made into a slurry by forcing it repeatedly through a hypodermic needle by means of a syringe. A non-ionic detergent ("Brij 58"; see Hall et al, 1975) was added to a final concentration of 0.10% and the mixture placed in an ice bath for 30 min and agitated vigorously every 5 min. The tonicity and pH of the mixture was then restored to physiological levels by adding 1/10th vol.…”

The shedding of viable cells into the local lymph by tumours growing in the gut of rats

“…The first step in the metastasis of malignant tumours is likely to be the shedding of cells into the local tissue fluid (lymph) but it is difficult to study this process under anything approaching "physiological" conditions (Weiss et al, 1980). The lymphatic systems of laboratory rodents are too small usually for direct experimentation, and although this difficulty of size can be overcome by using tumour-bearing sheep (Hall et al, 1975) the nature of the available tumours and the lack of inbred animals pose other severe problems.By excising the mesenteric lymph nodes, allowing a period for the regeneration of the lymphatic vessels, and then cannulating the thoracic (or intestinal) duct, it is possible to collect peripheral (i.e. afferent to the erstwhile mesenteric nodes) intestinal lymph (Hall et al, 1977).…”

“…The first step in the metastasis of malignant tumours is likely to be the shedding of cells into the local tissue fluid (lymph) but it is difficult to study this process under anything approaching "physiological" conditions (Weiss et al, 1980). The lymphatic systems of laboratory rodents are too small usually for direct experimentation, and although this difficulty of size can be overcome by using tumour-bearing sheep (Hall et al, 1975) the nature of the available tumours and the lack of inbred animals pose other severe problems.…”

“…The lymphatic systems of laboratory rodents are too small usually for direct experimentation, and although this difficulty of size can be overcome by using tumour-bearing sheep (Hall et al, 1975) the nature of the available tumours and the lack of inbred animals pose other severe problems.…”