Extended Data Fig. 3: IgM natural antibodies and sera from naive animals bind to Leishmania parasites.
From: Leishmania genetic exchange is mediated by IgM natural antibodies
(a,b) Sera from naive or Leishmania-infected adult mammals were used as indicated. IgG (a) or IgM from naïve serum (b) ELISA performed using recombinant K39 (rK39) protein or Leishmania lysate (LL) as target antigens. Statistical analysis by Mann-Whitney test between groups, *P < 0.05, **P ≤ 0.01. n = 4. (c) Leishmania clumping pattern 2 h after incubation with naïve or Leishmania-infected sera. L. major parasites were incubated in complete Schneider’s supplemented with 5% naïve or Leishmania-infected sera from adult mammals as indicated (n = 4-5). Scale bars = 50 µm. (d) Western blot of L. major enriched cell wall membrane preparation incubated with naïve adult human sera detected by anti-IgM (left panel). Right panel, L. major enriched cell wall membrane preparation incubated with only secondary antibody as control. n = 2. (e) Purified naïve IgM (IgMn) binding to Leishmania performed ELISA using LL or a negative control protein (bovine serum albumin) as target antigens. Statistical analysis by Mann-Whitney test between groups, ****P ≤ 0.0001. n = 3. (f) PNA agglutination does not promote Leishmania hybrid formation. Images taken 12 h after incubating parasites with varying concentrations of PNA. Scale bars = 50 µm. (g) Data summary of hybrid formation from in vitro crossing of L. major parental lines 1 and 2. Mating wells were prepared with 50 µg/mL IgM or with 6.25, 12.5, 25 and 50 µg/mL PNA in complete Schneider’s media. ELISAs data represented by individual values scatter plots. Dashed bars, medians.
