Colony formation by T-lymphocytes infiltrating human tumours.

Cell suspensions from 10 breast cancers and 4 melanomas were cultured in soft Agar with phytohaemagglutinin-stimulated lymphocyte-conditioned medium (PHA-LCM). Between 3 and 10 days, some of the plated cells formed colonies of greater than 20 cells indentifiable as T-lymphocytes by morphology, cytochemical staining and capacity to form rosettes with sheep erythrocytes. The frequency of colony-forming T-lymphocytes was 0-32 per 2 X 10(5) viable cells plated, and correlated with the degree of lymphocytic infiltration within the tumour. This cloning procedure appeared to select for a subpopulation of T-cells which is well represented within primary tumours. It should prove useful for investigating lymphocyte tumour relationships in vivo.