Effects of Malnutrition on the Expression of Daintain/AIF‐1 in the Gut Mucosa of Pigs

Abstract

The allograft inflammatory factor (AIF-1/daintain) is a hormone-like peptide produced by activated monocytic cells in a variety of traumatic, inflammatory and degenerative lesions. Gut-derived AIF-1 has been shown to modulate insulin production and to attenuate autoimmune diabetes. As the localization of this gastrointestinal peptide in the porcine duodenum is not known and the pig is a convenient model for the study of nutritional modulation of the mucosal immune compartment, we have localized expression of AIF-1 by immunohistology in the duodenum of either malnourished (energy and protein supply 50% of demands, n = 5) or optimally fed pigs (n = 5). AIF-1 macrophages were predominantly located at the villus tip. The number of positively stained cells per high-power field was significantly (P < or = 0.001) higher in the malnourished pigs (74.6 +/- 2.44; least square means +/- SEM) compared to optimally fed pigs (32.56 +/- 1.99). It is likely that the effect in malnourished pigs can be explained by a more pronounced antigen contact of macrophages due to loss of epithelial integrity. Thus, AIF-1 is a novel marker for the study of the nutritional regulation of the mucosal immune system of the pig. AIF-1 expression in the duodenum was further validated by polymerase chain reaction and sequencing. Surprisingly, we detected a slight deviation from the original sequence (probably representing an allelic variation) and an AIF-1 splice variant, previously not known to occur in pigs.

Allograft inflammatory factor‐1 regulates trinitrobenzene sulphonic acid‐induced colitis

“…It was also shown in a human system that mRNA of AIF‐1 was expressed in the liver, colon and small intestine 10,14 . However, immunological functions of AIF‐1 in the gastrointestinal tract have been totally unclear, although Mentschel et al 15 . reported that AIF‐1 expression was elevated in the gut mucosa of malnourished pigs compared to optimally fed controls.…”

Preparation and Identification of Monoclonal Antibodies Against Daintain

“…(3) Also, daintain is a novel marker for the study of nutritional regulation of the mucosal immune system of the pig. (4) Daintain shares a widespread identical amino acid sequence with allograft inflammatory factor-1 (AIF-1), (5) which is a 17-kDa interferon-␥-inducible Ca 2ϩ -binding protein and is encoded within the HLA class III genomic region. (6) AIF-1 was originally cloned from activated macrophages in a rat undergoing chronic transplant rejection.…”