A factor isolated from Taenia solium metacestodes stimulates T lymphocytesto proliferate and produce gamma interferon

A metacestode factor (MF) isolated from live metacestodes of Taenia solium suppresses humoral and cellular responses, and inhibits the inflammatory re action around metacestodes implanted subcutaneously in mice. When this MF i s digested with RNase (dMF), it loses the suppressive capacity, but acquire s T-cell stimulant ability. By filtering MF through a Bio-gel P6 column, tw o components were separated. The first (F1) was suppressive, while the seco nd (F2) stimulated T cells to proliferate, In these experiments, F2 or dMF was used with mouse spleen cells in stimulation assays in vitro. Spleen cel ls from mice treated with F2 or dMF were also stimulated with concanavalin A (Con-A) ex vivo. Flow cytometry analyses were performed to estimate cell proliferation. intracellular cytokine production. and restoration of CD4(+) cells. Spleen lymphocytes from mice previously treated with F2 or dMF and then stimulated with Con-A ex vivo exhibited a significant increase in cell proliferation and gamma interferon production by CD4(+) (P < 0.05) and CD8 (+) cells. These effects were concentration-dependent and inversely correla ted with the amount of dMF or F2. Similar results were observed in normal m ouse spleen T cells incubated with F2 or dMF and Con-A in vitro. Finally, d MF induced a significant restoration of CD4(+) cells in mice depleted of th ese cells.