. "6 Manipulating Host-Microbe Interactions: Probiotic Research and Regulations." Ending the War Metaphor: The Changing Agenda for Unraveling the Host-Microbe Relationship - Workshop Summary. Washington, DC: The National Academies Press, 2006.
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Ending the War Metaphor: The Changing Agenda for Unraveling the Host-Microbe Relationship - Workshop Summary
Research in Suzanne Cunningham-Rundles’ lab concerns the possible role of probiotic bacteria in the modulation of the host immune response. In their contributed paper, Cunningham-Rundles and coworkers describe recent studies characterizing the initial formation of mucosal immunity through interaction with the GI microflora—an interaction that may induce specific and persistent immune response patterns in the host, and which could potentially be manipulated with probiotics. In particular, they explore the potential of probiotic lactic acid bacteria to enhance systemic, as well as mucosal, immune response in infants and young children and the use of probiotic bacteria as antigen delivery vehicles or adjuvants in HIV-1-positive patients.
Based on the results of their efforts, Cunningham-Rundles noted in workshop discussion that she and her coworkers are preparing an investigational new drug (IND) application for probiotic-fortified formula intended for use in low birth-weight infants. The IND application process and its implications for probiotic development are described in the subsequent essay on U.S. probiotics regulatory issues by workshop participant Julienne Vaillancourt of the FDA’s Office of Vaccine Research and Review in the Center for Biologics Evaluation and Research, which has regulatory authority over the development and marketing of probiotics for clinical treatment indications.
To date, all probiotics on the U.S. market fit the FDA definition of a dietary supplement (“a product taken by mouth that contains a dietary ingredient intended to supplement the diet”). Although this situation is expected to change, there is little incentive for manufacturers of probiotics—currently marketed as dietary supplements—to develop them as biotherapeutics given the rigors and expense of the associated review and regulation process. A similar situation currently exists in Europe, where several countries are currently considering legislation to require proof for health claims by manufacturers of dietary supplements. In the United States, the dietary supplement/biotherapeutic dichotomy is likely to remain a part of probiotic regulations for some time. However, as Vaillancourt notes, the regulatory process for biotherapeutics is likely to expand and change to reflect new knowledge; she identifies several issues that need to be addressed through collaborative efforts between all involved parties.
It is not only clear that guidelines and regulations governing probiotics must be revised to reflect recent research findings, but also that this goal is a fast-moving target. In the final contribution to this chapter, workshop presenter Lorenzo Morelli and coworkers describe the process and considerations that produced the recent FAO/WHO guidelines for the evaluation of probiotics in food and raise a variety of cutting-edge issues that need to be addressed in subsequent guidelines, including:
new genomic techniques that allow enhanced characterization of the gut microbiota,
evaluation of emerging methods that allow assessment of bacteria-epithelial interactions,