Accessibility of circulating immunoglobulin G to the extravascular compartment of solid rat tumors.

We have measured the rate of influx (kin) of normal rat immunoglobulin G (IgG) from the blood into the fluid surrounding the cells of three syngeneic rat fibrosarcomas as well as rat skin, muscle, lung, and kidney. Also measured was the rate of efflux (kout) of IgG from the tumor and tissue back into the circulation. The value of kin ranged from 0.

Factors influencing localization of labeled antibodies in tumors.

Recent success with antibody to carcinoembryonic antigen makes it desirable to survey the practicality of producing other tumor-localizing antibodies for diagnosis and therapy. General procedures for reaching these goals are outlined. Experimental animal studies show some progress; detecting moderate-sized tumors by scanning appears a reasonable goal, but there is a basic lack of knowledge regarding the extent to which tumors express tumor-specific or associated antigens in vivo.