Effect of Oral Administration of Bacterial Extracts on the Bactericidal Capacity of Polymorphonuclear Leucocytes in Children with Recurrent Respiratory Infections

The effect of orally administered hacterial extracts givenintermittently over 16 weeks on the bactericidal capacity of polymorphonuclear leucocytes (PMNs) in children with recurrent respiratory infections was investigated using a luminol-amplified chemiluminescence assay. Chemiluminescence of PMNs stimulated with zymosan or N.formyl­ methionyl-Ieucyl-phenylalanine (fMLP) before and after treatment with bacterial extracts or intramuscular benzanthine penicillin was evaluated. Chemiluminescenceinduced by opsonizedzymosanincreased significantly (P < 0.05)after treatment with bacterial extracts, whereas no significant changes were observed in the fMLP-stimulated PMNs. Long-acting penicillin treatment did not significantly affect zymosan­ or fMLP-stimulated chemiluminescence. The data suggest that orally administered bacterial extracts can increase the opsonic capacity of serum and thus the bactericidal capacity of PMNs in subjects with recurrent respiratory infections.