Fig. 1

Possession of an XX vs. XY sex chromosome complement influences humoral responses to HKSP immunization. Immune responses against HKSP were assessed in FCG females and males one-week post-HKSP immunization. Numbers of HKSP-specific IgM-secreting B cells (A) and percentages of CD138 + plasma cells (B) were measured using ELISpot and flow cytometry, respectively. To assess the impact of sex hormones on sex chromosome-dependent phenotypes, percentages of CD138 + plasma cells were assessed in sham-operated (Sham) vs. gonadectomized (Gdx) female and male FCG mice following the same immunization protocol (C). Main effects of chromosomes and gonadal sex on variables assessed in A and B are presented by graphing the predicted (LS) means of each variable (D). Data in A-C are represented as the mean ± SEM with each data point representing one mouse. Statistical analyses by two-way ANOVA followed by Sidak’s multiple comparisons tests (A, B) or three-way ANOVA followed by Tukey’s multiple comparisons tests (C). Comparisons in graphs are representative of multiple comparisons tests; *p < 0.05; **p < 0.01; ***p < 0.001. ANOVA main and interactive effects are provided in Additional file 9: Tables S1-S2