The immune status of avian sarcoma virus-infected chickens as a determinant of sarcoma growth pattern and viral antigen expression.

Patterns of sarcoma growth were compared in immune-suppressed (cyclophosphamide-treated) vs nonsuppressed avian sarcoma virus-infected chickens. Sarcomas were initially induced in suppressed or nonsuppressed line FP chickens (donors) by wing web inoculation with clone 85, an avian sarcoma virus encoding an envelope glycoprotein that is non-antigenically cross-reactive with endogenous viral glycoprotein. Sarcoma tissue from these donors was then implanted in the wing webs of suppressed or nonsuppressed recipients to compare the effects of immune suppression of donors and of recipients. Sarcoma tissue that had been excised from suppressed donors and implanted in the wing webs of nonsuppressed recipients evidenced a much greater capacity than sarcoma tissue from nonsuppressed donors to yield distal sarcomas localized to visceral organs and to induce expansion by infection-mediated recruitment of new sarcoma cells. In contrast, immune suppression of the recipients of sarcoma tissue from nonsuppressed donors was not significantly enhancing for these effects. The enhancement achieved by immune suppression of the donors correlated with a markedly increased level of virus production and viral antigen expression by the primary (wing web) sarcoma cells from these donors.