Figure 5.

Passive immunization protects ΔF508 mice from Coxsackievirus B3 (CVB3) infection and tissue damage. Antibody-positive (immune) and negative (nonimmune) sera was prepared from previously infected wt mice, as described in the Supplementary Material Methods section. Passive immunizations were performed 24 hours prior to CVB3 challenge by the administration of 400 µl (intraperitoneal) immune or nonimmune sera to the ΔF508 mice. A, The neutralizing capacity of sera drawn at 24 hours after passive immunization was measured at 2 separate dilutions, 1:100 and 1:1000, as described in the Supplementary Material Methods. The percentage of animals that had sera with virus-neutralizing capacity is shown as the percentage of all animals in each respective group. Black and white bars indicate animals receiving immune (AB⁺; n = 5) and nonimmune (AB⁻; n = 5) sera, respectively. B, C, Passively immunized ΔF508 mice were infected with CVB3 (10² plaque-forming units [PFU]/mouse). Blood was drawn on days 3 and 4 postinfection for viremia measurements (B). C, On day 7 postinfection, the mice were sacrificed and the indicated organs were retrieved for histological analysis and measurements of replicating virus particles. Note that in the group receiving nonimmune serum, one mouse had to be sacrificed on day 6 postinfection due to CVB3-induced illness. The results are presented as log₁₀(PFU/g wet tissue or mL blood) and represents means ± SD. D, Representative images of pancreas sections from CVB3-infected ΔF508 mice receiving antibody-negative (AB⁻; n = 5) or antibody-positive (AB⁺; n = 5) sera, respectively. Upper panels, H&E staining. Lower panels, immunohistochemistry using primary antibody detecting insulin positive cells within the pancreas parenchyma. Original magnification × 10. *P < .05, **P < .01. Fisher exact test (A) and Mann–Whitney test (B, C).