Fig 5. Loss of Notch2 dimerization expands the splenic MZB compartment in the presence of mites.

A. FACS analysis of N2^RA/RA fur mite–infested mouse spleens revealed an expansion the MZB compartment relative to WT (+/+). Values for MZP, F0, and T₂ splenic B-cell populations were not significantly different; n = 11. B. The MZB cell compartment in heterozygotes. C. LPS-induced differentiation and IgM production in vitro and serum levels of IgM in vivo; n = 4. D. Peritoneal B1a B-cell compartment in mite-infested WT and N2^RA/RA mice (n = 2). E. The MZB cell compartment in N2^RA/RA mice after treatment with permethrin, an immunosuppressant used to manage fur mite infestation (PP), after LPS, or after 6 weeks of treatment with HDM extract. (*p < 0.05). Note, although a slight trend is seen in mite-free animals, power analysis indicates it would take 212 mice displaying this trend to reach significance. For LPS-treated mice, it would take 41 animals displaying this trend to reach significance. Only 4 mice were sufficient to reach significance after treatment with HDM. In (A-E) p-values generated by 2-tailed t-test. Error bars represent SD. F. Proliferation in the splenic marginal zone of mite-infested mice: (Fa) The spleen from a mite-infested control animal or (Fb) from N2^RA/RA mice. Boxed region magnified in Fc and again, in Fc’, asterisk and dot provided for orientation. Magnification noted. (Fd, d’) 60× view of marginal zone from control and HDM-treated N2^RA/RA mice. Raw data in S1 Data. F0, Filial generation 0; FACS, fluorescence-activated cell sorting; FoB, follicular B-cell; HDM, house dust mite; IgM, immunoglobulin M; LPS, lipopolysaccharide; MZB, marginal zone B-cell; N2^RA/RA, Notch 2 Arg¹⁹³⁴Ala homozygous; ns, not significant; P, postnatal day; PP, post-permethrin; T₂, type 2 cell; WT, wild-type.