The immune activation mechanism of heat killed probiotics 

(High concentrated heat killed probiotics more than 1 trillion/g = Immunobiotics) 

For decades, 'to reach the intestines alive' marketing strategy has led the probiotics market. 
However, consumers are now perplexed with the usage of the slain bacteria(Killed probiotics) by leading lactobacillus manufacturers. 

◎ Physiological activation of living lactic acid bacteria (LAB)

Let's look at the physiology of the living lactic acid bacteria(containg probiotics) and then start. 
Living lactic acid bacteria can reach the intestine and increase its population as a beneficial intestinal bacteria to prevent the settlement and proliferation of harmful bacteria. 
It has a purpose of living probiotics.

Therefore, as a functional health food, it specifies the function of ‘Increasing the useful bacteria & decreasing the harmful bacteria and helping the defecation activities’. Now, the most important factor in evaluating probiotics is “Does the probiotics really reach the intestines alive?” Regretfully, academic authority has strong negative views on consumed living bacteria settling and surviving in the intestinal tract. In fact, yogurt starter which is used for fermented milk in the market is often chosen for its stable fermentation and taste rather than for its health benefits. In short, it is for the production of fermented milk products.  

It was mentioned publically that "There is no possibility that Bulgaricus, Thermophilus, etc. will survive the bile acid or stomach acid and survive in the intestinal tract (S. Gilland, Microbiology Review, 1990). 

This immunization occurs in the Peyer's Patch, an immune system that is distributed in the intestine, and more precisely, it's the M-cell(microfold cell) inside the Peyer's Patch that allows microbes to come in and meet with the dendritic cell, or the macrophage. Through these mechanisms the information transfer in cell chain is made. 

It not only suppresses the infection bacillus, but also indicates antigen that is important to the immune system and creates cytokines as well. 
Mecinikov also studied killed lactic acid bacteria (heat treated Bulgaricus more than 100 years ago) and found & noted that even the slain bacteria(Heat-killed bacteria) had a physiological effect.  

Later, a vaccine by using the slain bacteria was developed by Pasteur. Through this development of the new vaccine, the slain bacteria was able to emerge from its dishonorable image of being just ‘dead and useless germ’, and furthermore, show its true value.  

The advantage of LAB is that it is okay to consume in large quantities because there are no side effects, making it simple & easy to consume enough amounts to show physiological activity. 

As mentioned above, ingestion of these killed lactic acid bacteria stimulates immune cell, and becoming food for white blood cells, it produces various cytokines such as Interleukin, Tumor necrosis factor, Interferon, and also performs immune-modulation by inhibiting them.