Studies of the paw test and tumor-associated immunosuppression in mice.

Specific paw test reactivity to tumor cells was transferred to normal mice using lymphoid cells or serum from mice with a growing or surgically excised methylcholanthrene-induced transplantable sarcoma. When the donors had been sensitized to PPD and to tumor, normal recipients of lymphoid cells became reactive by specific paw test to tumor cells and PPD. Normal recipients of serum from the same donors also became reactive to tumor cells. Normal recipients of serum from tumor-bearing mice developed depressed PHA paw tests. Adoptive transfer with cells or serum of paw test reactivity to tumor and PPD was unsuccessful when recipients had large tumors. This was the case when the recipients had either tumor of the same line or that of a separate line that did not cross-react antigenically.