Aβ-peptide liposomes induce IgG responses independent of CD40L and CD28. (A) Anti-Aβ IgG antibodies in the sera of WT, CD40L^−/−, and CD28^−/− mice receiving Aβ-peptide liposomes as indicated by arrows. Results are expressed as mean ± SD (n = 6 per group). (B) Analysis of anti-Aβ IgM and in the sera of WT, CD40L^−/−, and CD28^−/− mice from day 7. Results are expressed as mean OD values at a dilution of 1/100 + SD (n = 6 per group). (C-E) Analysis of anti-Aβ IgG subclasses in the sera of WT, CD40L^−/−, and CD28^−/− mice receiving Aβ-peptide liposomes. Analysis of IgG subclasses were done on sera prepared from blood on day 28. Results are expressed as mean OD values at a dilution of 1/400 + SD (n = 6 per group).