TABLE 2.

Reciprocal recombination experiment^a

Cell type	Fragmentb	RVS IgAa (OD units)	RVS IgAb (OD units)	Total IgAa (ng/ml)	Total IgAb (ng/ml)
B1a/non-B1b	SI	0	1.68 ± 0.54	160 ± 32	306 ± 93
	LI	0	1.31 ± 0.60	212 ± 58	374 ± 136
B1b/non-B1a	SI	2.07 ± 0.23	0	285 ± 70	122 ± 13
	LI	2.05 ± 0.50	0	367 ± 114	201 ± 63
PECa	SI	3.25 ± 0.60	0	204 ± 63	0
	LI	3.22 ± 0.43	0	228 ± 62	0
PECb	SI	0	1.82 ± 0.04	0	156 ± 1
	LI	0	1.78 ± 0.28	0	165 ± 6

^aThe production of RV-specific and total IgA in small and large intestinal lymphoid tissues of RV-infected SCID mice reconstituted with peritoneal B1 and non-B1 cells of a versus b allotypes is shown. SCID mice were inoculated with EDIM RV at 12 weeks of age and 3 weeks later were reconstituted with reciprocal combinations of peritoneal B1 and non-B1 cells of allotypes a versus b (indicated as roman superscripts). Unseparated peritoneal exudate cells (PEC) of each allotype served as positive controls. Cultures of small and large intestine fragments were performed 2 to 3 months later, and supernatants were tested by ELISA for the presence of RV-specific and total IgA of allotypes a and b. The data represent the means ± the SEM. The number of fragments per tissue per group of mice ranged from 12 to 24. 

^bSI, small intestine; LI, large intestine.