Both B1a and B1b cells produce IgMFt.
Rag1-/- mice reconstituted with purified B1a or B1b cells were immunized i.p. with LPSFt. (A) Total number of peritoneal B1a or B1b cells in reconstituted Rag1-/- mice. Level of IgMFt and total IgM in serum was measured on day 7 p.i. (B) Reconstituted Rag1-/- mice were then infected with Ft (4x103 cfu) and euthanized seven days later for measurement of bacteria burdens in organs. One representative experiment of two is shown. Data are expressed as mean ± SD. One-way ANOVA Tukey Post-test. *p<0.05, **p<0.01, ****p<0.0001. See also S2 Fig.