Mouse lymphoblasts lose their immunogenicity and susceptibility to specific cytotoxic T lymphocyte lysis during maintenance in culture

Sustained exposure to bacterial antigen induces interferon-γ-dependent T cell receptor ζ down-regulation and impaired T cell function

T cell antigen receptor zeta chain down-regulation and impaired in vitro T cell function have been described in cancer and autoimmune and infectious diseases. However, the immunological basis for this phenomenon is unknown. Sustained exposure to antigen and chronic systemic inflammation, factors shared by the various pathologies, might account for this phenomenon. We developed an in vivo experimental system that mimics these conditions and show that sustained exposure of mice to bacterial antigens was sufficient to induce T cell antigen receptor zeta chain down-regulation and impair T cell function, provided an interferon-gamma-dependent T helper type 1 immune response developed. This indicates zeta chain down-regulation could be a physiological response that attenuates an exacerbated immune response. However, it can act as a 'double-edged sword', impairing immune responses to chronic diseases.

Heat inactivation of fetal calf serum is not required for in vitro measurement of lymphocyte functions

This study was undertaken to test whether fetal calf serum (FCS) must be heat inactivated before use in tissue culture. We tested various immune functions of lymphocytes growing in medium containing non-treated and heat-inactivated FCS. The data clearly show that heat inactivation of the serum is not mandatory. In some cases, the addition of untreated FCS resulted in elevated response levels, while maintaining immune function specificity.