Figure 6. CD4⁺ T cells-dependent B cell activation on vaccine efficacy.

Selective depletion of CD4⁺ T cells prevented activation of 6OXY-specific B cells and subsequent 6OXY-KLH effects in C57Bl/6 mice. A) Depletion of CD4⁺ T cells, but not CD8⁺ T cells in peripheral lymph nodes and spleen. T cells are shown as log₁₀. B) The frequency of 6OXY-specific IgM^high and swIg B cells in enriched blood 14 days after the first immunization. C) Depletion of CD4⁺ T cells blunted vaccine efficacy against oxycodone distribution measured on day 35, 7 days after the last immunization. D) In C57Bl/6 mice, an increased number of 2W1S-specific CD4⁺ T cells in spleen biopsy prior to immunization correlated to subsequent greater efficacy against oxycodone in mice vaccinated with 6OXY-OVA^2W. Data are mean±SEM. Data consists of two independent experiments for a total of (A-C) n=6 and (D) n=9 each group. *** p<0.001 compared to control or as indicated by brackets.