Optimization of lymphocyte proliferation assay for cells with high spontaneous proliferation in vitro: CD4+ T cell proliferation in bovine leukemia virus infected animals with persistent lymphocytosis.

摘要

Evaluation of antigen specific lymphocyte proliferation is extremely difficult with cells displaying high spontaneous proliferation in vitro, such as bovine leukemia virus (BLV) and T cell leukemia virus type I (HTLV-I) infected cells. We introduced modifications to a standard proliferation protocol, and for the first time report antigen specific proliferation in BLV infected animals with persistent lymphocytosis (a benign proliferation of B lymphocytes). Serum (autologous, heterologous or fetal) but not medium was a major factor contributing to spontaneous proliferation. Spontaneous proliferation was strongly serum concentration dependent and reducing serum to 0.5-1% resulted in decreased background proliferation and development of a functional assay. Addition of indomethacin (3-6 micrograms/ml) further increased antigen specific responses not only from persistently lymphocytotic but also from lymphosarcoma animals. Thus, this modified proliferation protocol can be used in infections where background proliferation hinders evaluation of antigen-specific CD4+ T cells.