Aβ-peptide liposomes induces a rapid, robust, and persistent antibody response independent of CD4⁺ T cells, α/β T cells, and γ/δ T cells. (A) Anti-Aβ or (B) anti-OVA IgG antibodies in the plasma of WT mice or CD4-depleted WT mice immunized with Aβ-peptide liposomes or OVA/Alum, respectively; depletion was done by weekly i.p. injections of 100 μg (optimized in house, data not shown) anti-CD4 antibody (clone YTS191.1; AbD Serotec) starting 3 days before immunization, and verified by flow cytometry on blood sampled on days 0, 7, 14, and 21. Results are expressed as mean ± SD (n = 8 per group). Arrows indicate time of immunization (d0); ***P < .001. (C) Anti-Aβ IgG antibodies in the plasma of MHC II^−/− and WT mice receiving Aβ-peptide liposomes at day 0 and 7. Results are expressed as mean + SD (n = 6 per group). (D) Anti-Aβ IgG antibodies in the sera of WT, nude, and TCR^−/− mice receiving Aβ-peptide liposomes (as indicated by arrows). Results are expressed as mean ± SD (n = 6 per group). (E) Analysis of anti-Aβ IgM in the sera of WT, nude, and TCR^−/− mice from day 7. Results are expressed as mean OD values at a dilution of 1/100 + SD (n = 6 per group). (F-H) Analysis of anti-Aβ IgG subclasses in the sera of WT, nude, and TCR^−/− mice receiving Aβ-peptide liposomes. Analysis of IgG subclasses were done on sera prepared from blood on day 28. Results are expressed as mean + SD OD values at a dilution of 1/400 (n = 6 per group).