Opposing impact of <i>L. sigmodontis</i> adults and MF on humoral response to TD vaccination.

<p><b>(A)</b> Six- to eight-week-old BALB/c mice received 10,000 MF i.v. (green squares, n = 10) or were left untreated (white squares, n = 10). Both groups were vaccinated with 100 µg DNP-KLH/Alum i.p. immediately. Control mice (black circles, n = 2) received 10,000 MF i.v. but were not immunized. DNP-specific IgG1, IgG2a and IgG2b was quantified in sera. Results are expressed as mean ± SEM of pooled data derived from two independent experiments. Asterisks indicate significant differences of the mean of DNP-specific Ig in non-treated and MF-treated mice (Two-way ANOVA). <b>(B)</b> Six- to eight-week-old BALB/c mice were naturally infected with <i>L. sigmodontis</i> (closed squares) or left non-infected (white squares, n = 8). Day 60 <i>L. sigmodontis</i>-infected mice received 10,000 MF i.v. additionally (purple squares, n = 10) and all groups were vaccinated with 100 µg DNP-KLH/Alum i.p. immediately. Control mice were also vaccinated with 100 µg DNP-KLH/Alum i.p. and either infected for 60 days (blue squares, n = 2) or received purified MF only (green squares, n = 4). Non-vaccinated control mice were infected for 60 days and received MF i.v. (black squares, n = 2) or just received MF i.v. (black circles, n = 2). DNP-specific IgG2a was quantified in sera. Results are expressed as mean ± SEM of pooled data derived from two experiments. Black asterisks indicate significant differences of the mean of DNP-specific Ig in non-infected and infected BALB/c mice. Purple asterisks indicate significant differences of the mean of DNP-specific Ig in non-infected and infected MF-treated mice. Green asterisks indicate significant differences of the mean of DNP-specific Ig in MF-treated non-infected and MF-treated day 60 <i>L. sigmodontis</i>-infected mice (student's t-test).