Evaluation of risk and benefit of oral immunomodulation using heat-killed enterococcus faecalis FK-23 preparation in healthy dogs.

: The risk and benefit of oral immunomodulation using heat-killed Enterococcus faecalis FK-23 preparation (FK-23) were evaluated in healthy dogs. Dogs were administered perorally 100 mg/kg of FK23 daily for 3 months. FK-23 did not affect the findings of complete blood count, leukocyte differential count, blood chemistry, serum electrolyte, radiography, or physical conditions of the dogs tested. Increase in myeloid/erythroid ratio and granulocytic lineage was found in bone marrow of the FK-23 treated dogs. Neutrophil function assessed by zymosan-dependent chemiluminescence was activated by treatment of the drug. FK-23 also stimulated in vitro lymphocyte blast transformation of PHA, Con A, and LPS. FK-23 thus appears to be a useful immunomodulating drug to stimulate non-specific host immune responses without adverse side effects.