The general goal of this project is to define the mechanism of mitogenesis in nontransformed human lymphocytes and the relationship of transforming gene products to this process. The work focuses on the transition of resting, GO phase lymphocytes from peripheral blood into the cell cycle in response to three required signals: (1) mitogenic lectin or antigen; (2) serum factors; and (3) interactions between cell types. In transformed cells control of proliferation by these signals is relaxed. The aims concentrate on defining the role of a limited number of intracellular proteins that are preferentially expressed or synthesized in response to these signals. The hypothesis is that these proteins are part of the intracellular signal transduction pathway leading to cell proliferaton. The aims are: (1) determination of the expression and synthesis of proteins associated with proliferative response in mononuclear cell subsets and transformed cells; (2) determination of kinetics of production and degradation of response-associated proteins and relationship to known transforming gene products; and (3) determination of association between signal type and expression of proteins. The methods are designed to dissect the effects of each signal type on protein expression and resulting proliferation, aggregation, or adhesion of the cells. The methods include: separation of cell types by surface markers and density, determination of patterns of protein expression and synthesis by one-\and two-dimensional eletrophoresis, kinetic assays for proliferation, binding of antibodies to known oncogene products, and tentative steps toward physical isolation of response-associated proteins. A major justificstion for working with this complex cell system is that it represents a normal rather than an imposed quiescent state in cells that can be moved partway along the signal transduction pathways by separate signals. The results are expected to contribute significantly to the understanding and ultimate control of human malignancy. (LB)