MODULATION OF A SPECIFIC HUMORAL IMMUNE-RESPONSE AND CHANGES IN INTESTINAL FLORA MEDIATED THROUGH FERMENTED MILK INTAKE

This study was undertaken to elucidate whether eating a fermented milk containing Lactobacillus acidophilus La1 and bifidobacteria could ind uce changes in intestinal flora and modulate the immune response in ma n. Volunteers consumed a fermented milk containing L. acidophilus La1 and bifidobacteria over a period of three weeks during which an attenu ated Salmonella typhi Ty21a was administered to mimic an enteropathoge nic infection. A control group ate no fermented foods but received the S. typhi Ty21a. Faecal flora analyses showed an increase in L. acidop hilus and bifidobacterial counts during fermented milk intake. The spe cific serum IgA titre rise to S. typhi Ty21a in the test group was > 4 -fold and significantly higher (P = 0.04) than in the control group. A n increase in total serum IgA was also observed. These results indicat e that lactic acid bacteria which can persist in the gastrointestinal tract can act as adjuvants to the humoral immune response.