QUANTIFICATION OF ANTIGEN-SPECIFIC IMMUNOGLOBULIN-A AFTER ORAL BOOSTER IMMUNIZATION WITH OVALBUMIN IN MICE MONO-ASSOCIATED WITH SEGMENTED FILAMENTOUS BACTERIA OR CLOSTRIDIUM-INNOCUUM

Segmented filamentous bacteria (SFB) are known to stimulate the mucosa l immune system. Here, the effect of SFB on oral booster immunization with ovalbumin was investigated. Mice mono-associated with SFB or Clos tridium innocuum were sensitized by intraperitoneal administration of 100 mu g ovalbumin with Freunds complete adjuvant. After 4 weeks, mice received 80 mg ovalbumin orally. A maximum IgA response was found 5 d ays after this booster immunization. Comparison of mice with SFB and m ice with C. innocuum revealed a much higher level of IgA in the gut lu men and more IgA secreting cells in the lamina propria of the SFB-asso ciated mice. However, no differences between both groups of animals we re found in specific levels of IgA secreting cells or luminal IgA agai nst ovalbumin. It is concluded that there is no enhancing effect of SF B after booster immunization when mice are primed intraperitoneally wi th ovalbumin. (C) 1997 Elsevier Science B.V.