Figure 4. Mice carrying a T-cell specific deletion of PARP-2 in a PARP-1-deficient background display defects in specific antibody response to T-dependent antigens.

Ten-to-twelve-week-old Cd4-cre;Parp-2^+/+;Parp-1^+/+, Cd4-cre;Parp-2^f/f;Parp-1^+/+, Cd4-cre;Parp-2^+/+;Parp-1^−/−, and Cd4-cre;Parp-2^f/f;Parp-1^−/− mice were i.p. injected with the T-dependent antigen TNP-KLH and sigma-system adjuvant. (A) T_fh cell development is impaired in Cd4-cre;Parp-2^f/f;Parp-1^−/− mice. Spleen samples from no-immunized mice and fourteen days after immunization, were collected and cells were counted and stained to detect by flow cytometry total CD4⁺ T-cells and T_fh cells (CD4⁺CXCR5⁺ PD1⁺ ICOS⁺). Graph showing the number of CD4⁺ and number and percentage of T_fh cells. (B) Serum was collected at the indicated time point, and TNP-specific IgM, IgG1, IgG2a, IgG2b and IgG3 were assayed by ELISA. Bars represent the mean ± SEM values of at least 7 mice of each genotype. *P < 0.05; **P < 0.01; ***P < 0.001.