The company has new results from a clinical trial that showed higher numbers of different types of white blood cells after subjects had consumed probiotics.
One of Probi's bacteria, not yet on the market, increased white blood cells that have previously been linked to the protection against type 1 diabetes.
"It's difficult to say how much this would do for a patient at this stage," said Per Bengtsson, the firm's chief executive.
But he added that the results could have an important role in future research into diseases in which the immune system attacks the body, such as diabetes, MS and rheumatism.
Further, the findings show "for the first time that you can get differential effects on the immune system by eating certain bacteria," Bengtsson told NutraIngredients.com.
The findings were reported at the European Conference on Probiotics and their Application in Krakow, Poland last weekend.
In another arm of the trial, carried out on 59 healthy people at the Sahlgrenska Hospital in Göteborg, Sweden, the volunteers consumed a strain of Lactobacillus plantarum for five weeks.
The researchers saw a significant increase in white blood cells known to fight disease, including CD4+ and CD8.
"These are markers of how healthy your immune system is," said Bengtsson.
"Since the results are obvious in healthy people, you would imagine that they could be quite significant in people who are ill," he added.
The study is the first clinical trial funded by Probi to investigate effects on the immune system. The firm is planning to present the results to Danone, already working with Probi on a product for gut health.
It will also approach clinical nutrition companies, said Bengtsson.