Abstract
CD4^+ helper T cells (Th) are classified into two typical subsets, Th1 and Th2, depending on the spectrum of cytokine production. Generally, Th1 cells predominantly induce cell-mediated immunity, and Th2 cells predominantly induce antibody-mediated immunity. Differentiation of naive CD4^+ Th into these subsets is affected by various conditions, one of which is believed to be the type of antigen involved. We have previously reported that the injection of lipopolysaccharide (LPS) in rats induced a large antibody production, while that of ovalbumin (OVA) induced a small antibody production. To examine the possibility that this immunological difference is depend on the properties of Th which are induced by respective antigens, we established cloned cells, which specifically proliferated in response to OVA or LPS, from the spleen cells of rats immunized i.p. with OVA or LPS. Five of each randomly selected clones were Th type, determined by positivity for W3/13 HLK (anti-rat T cell) and anti-CD4 ; these were designated OVA-specific and LPS-specific Th clones, respectively. All the selected OVA-specific Th clones showed Th1-like properties, e.g., they produced interleukin-2 and interferon, and induced a DTH response. All the selected LPS-specific Th clones showed Th2-like properties, e.g., they had B cell helper function. In our immunization system, the type of Th subset induced by immunization seems to be dependent predominantly on the type of antigen used.
