Polyclonal activation of human lymphocytes by bacteria

The proliferative response of human unseparated lymphocytes, T cells, and B cells to various bacterial strains was investigated. All the bacteria tested induced a proliferative response in unseparated lymphocytes and B cells. T cells were stimulated only after reconstitution with monocytes. Stimulation of umbilical cord blood lymphocytes suggests that the response is polyclonal. We interpret these and previous data as an indication of a common mechanism of resistance against infectious diseases.