increase of immune responses?

[hbkg at hitel.kol.co.kr]

It is well known that bacterial substances like fragmented poly
peptides in the blood can increase immune responses..
By the way, eating bacterial extracts (like Lactobacillus) 
for a long time orally is  helpful for that purpose?
Bacterial materials on the surface of white cells will
probably induce immune responses. I am curious about its
effectiveness in vivo...