Table 1. Experimental procedures and summary of the results.

	aly/aly reconstituted with		Gut LP
Experimental system	Type of B cells	Stromal cells	IgM+ B cells	IgA+ plasma cells	Data shown in
BM	Naive	-	-	-	Fig. 1
BM plus spleen	Naive	-	-	-	Fig. 1
PP	Primed	-	+	+	Fig. 1
Parabiosis with GFP Tg	Primed	-	+	+	Fig. 2
BM and parabiosis with RAG-2-/-	Primed	-	+	+	Fig. 3
BM B6 and	Naive	-	+	+	Fig. 4
LP GFPTg	Primed	+
BM GFP Tg and	Naive	-	+	+	Fig. 4
LP RAG-2-/-	-	+