DBA/2 mice fed a casein diet develop elevated casein-specific IgE in association
with a Th2-like cytokine pattern. In such mice, i.p. injection of heat-killed Lb. plantarum
L-137 inhibited casein-specific IgE production, although IgG1 levels actually
increased, compared to saline injected controls.105 There was a concomitant increase
in IL-12p40 synthesis by unstimulated peritoneal macrophages from Lb. plantarum
injected mice and an even greater increase in macrophages restimulated with
Lb. plantarum. Secretion of IL-4 by ConA-stimulated splenocytes was diminished
in L. plantarum injected mice, whereas IFN-γ production was not affected.
Human in vitro studies have demonstrated that three LAB strains (Lb. gasseri
ATCC no. 19992, Lb. johnsonii ATCC no. 33200, and Lb. reuteri ATCC no.