129 mice possess fewer Paneth cells than B6 mice.

<p>(A) Lysozyme (Lyz) staining of ileal tissue shown at 20× magnification from B6 and 129 mice. Inset shows high power view (40×) of single crypt. (B) Flow cytometry was used to quantify Lyz⁺ cells from the ileal epithelium of B6 and 129 mice. Data are representative of 3 independent experiments. (C) <i>Lyz</i> transcripts were measured using quantitative RT-PCR of ileal RNA extracts from SPF and GF mice. Copy number is normalized to <i>Gapdh</i>, and fold change is relative to the GF B6 group (*<i>P</i><.0001).