Modulation of the immune response to transplantation antigens. II. The effects of heterologous antisera on the growth of tumour allografts in mice

The effects of heterologous antilymphocytic sera (ALS) and anti-tumour sera on the growth of allogeneic tumour grafts in mice have been examined. Some ALS were highly active in promoting tumour growth, whilst the antisera raised against the tumours were not. The ALS appeared to act by delaying the onset of the immune response, and although a full cytotoxic response developed later the tumour was by then too large to be rejected. No clear evidence could be obtained that immunological enhancement plays a role in the in vivo effects of the ALS.