Commensal bacteria in the gastrointestinal tract play an integral role in both innate and humoral immunity. It is well established that this protective role can be maintained or modulated by the ingestion of probiotics. More recently, it has been shown that specific probiotic strains can influence the secretion of cytokines to help direct naïve helper T cells towards either a Th1 dominant, cell-mediated immune response or towards a Th2 dominant, humoral immune response. This paper will review current knowledge of the Th1: Th2: Th3/ Treg model of humoral immunity as well as introduce how strain-specific probiotics can be used therapeutically to help balance this immune response and therefore, help prevent and treat disease.
Leah G. Gillingham, MSc
Keywords: probiotics, immunity, Th-1 cells, Th-2 cells, cytokines