Social learning and innovation. Ice fishing communities on Lake Milles Lacs

Social learning took place largely outside the sphere of government and spurred substantial technological and institutional innovation. Unique patterns of networks, informal institutions and social learning environments delineate options for social learning that are more likely to succeed, to lead to implementation. The history of social learning on lake Mille Lacs showed that new formal institutions are not necessarily the best sites for social learning, and that forms of innovation and modes of learning cannot be separated. Interdependence and shared goals, and flexibility in role distribution appear as success factors. The diversity of learning sites in a community should not be understood as a problem, as an obstacle to central steering and education by government: it enables the community to adapt and survive

GIA EC₅₀ values of anti-PfRH5 and anti-PfAMA1 IgG against various Cambodian parasite isolates and the 3D7 parasite clone.

<p>Total IgG EC₅₀ value for Cambodian parasite isolates is the median of observed values for five individual rabbits; values in italics are extrapolated from observed values. Antigen-specific antibody EC₅₀ values are derived from fitting of a single curve to all available GIA data points for each antigen and each parasite (as depicted in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002991#ppat-1002991-g001" target="_blank">Figure 1E</a> and <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002991#ppat-1002991-g002" target="_blank">Figure 2</a>). For comparison, estimated EC₅₀ values of the total and antigen-specific IgG against the 3D7 parasite clone are also shown. 3D7 antigen-specific IgG values are as calculated in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002991#ppat-1002991-g001" target="_blank">Figure 1E</a>, whereas total IgG values are a mean, with 95% CI in parentheses, from eight independent experiments that have estimated the total IgG EC₅₀ of anti-PfRH5 and anti-PfAMA1, with a total of five immunized rabbits for each antigen (<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002991#ppat-1002991-g001" target="_blank">Figure 1B</a>, <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002991#ppat-1002991-g004" target="_blank">Figure 4A–B</a>, Reference 17]).</p

PfRH5 genotypes in parasites isolated from Cambodia.

<p>Amino acids are represented by single letter codes. ‘Polymorphism’ denotes the reference (3D7) allele, amino acid number and non-reference allele. The presence of two amino acids at a single locus indicates a mixed genotype. ‘?’ indicates unknown. ‘Non-3D7 allele frequency’ denotes the proportion of sequenced loci with a non-3D7 allele at that locus: Lab = 22 laboratory lines previously sequenced 14–16]. For comparison, we show allele frequencies estimated by genome sequencing for three major endemic regions 33], using the online database provided at <a href="http://www.malariagen.net/data" target="_blank">http://www.malariagen.net/data</a>. SEA = South East Asia (81 samples from Thailand and Cambodia), AFR = Africa (125 samples from Kenya, Mali and Burkina Faso) and PNG = Papua New Guinea (21 samples).</p><p>(S) indicates synonymous SNPs; italic text indicates SNPs not previously identified in laboratory-adapted parasite lines and with non-reference allele frequency >5% in at least one population of parasite isolates; bold text indicates SNPs with non-reference allele frequency >5% of laboratory-adapted parasite lines and parasite isolates; for all other SNPs, the non-reference allele frequency is ≤5% in all sequenced populations of parasite isolates.</p

GIA effects of anti-PfRH5 IgG in combination with polyclonal antibody specific for other merozoite antigens.

<p>Percentage GIA against the 3D7 parasite clone over increasing concentrations of total purified IgG from rabbits immunized with <b>A</b>) PfRAP3, <b>B</b>) PfMSP1, <b>C</b>) PfAMA1, <b>D</b>) Pf38, <b>E</b>) PfEBA175, <b>F</b>) PfRH2 and <b>G</b>) PfRH4, with (blue line) or without (solid black line) the addition of a fixed low concentration of PfRH5-immunized rabbit IgG (0.156 mg/mL) which, when used alone, gives approximately 25% GIA (dashed black line). Predicted additive effects were calculated according to Bliss independence (see <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002991#s4" target="_blank">Materials and Methods</a>) and illustrated as the red line on each graph. Data points represent the mean of triplicates from two independent experiments. Bars indicate SEM for all six replicates over two experiments. Asterisks indicate that the predicted and observed values differed significantly (*<i>P</i><0.05; **<i>P</i><0.01; ***<i>P</i><0.001, 2-way ANOVA with Bonferroni post-hoc testing).</p

Contour plots and isobolograms of GIA achieved by anti-PfRH5 IgG in combination with either anti-PfRH4 or anti-PfAMA1 IgG.

<p><b>Panel A,B</b>–Contour plots of GIA versus concentration of total IgG combined from rabbits immunized with either PfRH5 or PfRH4 (A), or with either PfRH5 or PfAMA1 (<b>B</b>). Each experiment was conducted independently. Black lines are contours linking anti-PfRH5 and anti-PfRH4 IgG combinations inducing 25%, 50% and 75% GIA (as labelled), obtained by interpolation between observed GIA values. Shaded area indicates 0–25% GIA (blue), 25–50% GIA (green), 50–75% GIA (orange), and 75–100% GIA (pink). Thin diagonal dashed line from origin indicates line of equal concentration of IgG from each component. <b>Panel C,D</b> – 50% GIA isobologram for anti-PfRH5 and anti-PfRH4 IgG (<b>C</b>) and anti-PfRH5 and anti-PfAMA1 IgG (<b>D</b>) combinations. Red line links the observed combination of anti-PfRH5 IgG and either anti-PfRH4 or anti-PfAMA1 IgG that induced 50% GIA, plotted on axes of anti-PfRH5 and anti-PfRH4/anti-PfAMA1 IgG concentration expressed as percentage of the EC₅₀. Dashed line illustrates 50% contour predicted if anti-PfRH5 IgG and the other antibody are Loewe additive. Diagonal x = y line from origin links points at which anti-PfRH5 and anti-PfRH4/PfAMA1 IgG concentrations (as proportion of EC₅₀) are equal; the letters M and N indicate the line intersections used to calculate Hewlett's synergy index. <b>Panel E</b> – GIA attained by mixing equal concentrations of anti-PfRH5 with anti-PfRH4 IgG (blue line), plotted against the total IgG concentration in the well shown on the lower x-axis (i.e. twice the concentration of each individual component). The solid red line indicates the GIA effect when anti-PfRH5 IgG is used alone at the concentrations on the lower x-axis (i.e. twice the concentration of anti-PfRH5 IgG in the antibody mixture), and the dashed red line indicates the GIA effect of anti-PfRH5 IgG alone at the concentration shown on the upper dashed x-axis (i.e. the concentration of anti-PfRH5 IgG present in the antibody mixture). The solid and dashed black lines indicate the same relationship for anti-PfRH4 IgG.</p

Measurement of GIA EC₅₀ of antigen-specific anti-PfRH5 and anti-PfAMA1 polyclonal rabbit antibodies.

<p><b>Panel A</b> - CFCA-measured antigen-specific antibody as a proportion of total IgG (measured by spectrometry) for each of ten rabbits. Individual points indicate mean of three measurements. <b>Panel B</b> - GIA vs. total IgG concentration, with lines connecting data for each of five PfRH5-vaccinated rabbits (red) and five PfAMA1-vaccinated rabbits (black). Each point is the mean of three replicate wells in two independent experiments, i.e. <i>n</i> = 6. Error bars indicate SEM. <b>Panel C</b> - GIA (from the experiments depicted in panel <b>B</b>) vs. antigen-specific antibody concentration (calculated for each sample using the data in panel <b>A</b>), for each of five PfRH5-vaccinated rabbits (red) and five PfAMA1-vaccinated rabbits (black). Each point is the mean of triplicate wells in two independent experiments. <b>Panel D</b> - antigen-specific antibody EC₅₀ values for PfRH5 and PfAMA1, calculated by interpolation from the data in panel <b>C</b>. Individual data-points and the median are shown. <b>Panel E</b> - Dose-response curve fitted to all GIA vs. antigen-specific antibody concentration data for the 3D7 parasite clone (multiple IgG dilutions for each of five rabbits for PfRH5 and PfAMA1). Dashed vertical lines indicate the fitted EC₅₀ value for anti-PfRH5 (red) or anti-PfAMA1 (black) IgG. Each GIA value is the mean of triplicate wells in each of two experiments (<i>n</i> = 6). Red indicates anti-PfRH5 samples; black indicates anti-PfAMA1 samples.</p

GIA synergies against the vaccine-heterologous FVO parasite clone.

<p>Percentage GIA against the FVO parasite clone over increasing gradients of concentrations of IgG from rabbits immunized with <b>A</b>) PfEBA175, <b>B</b>) PfRH2 or <b>C</b>) PfRH4 with (blue line) or without (solid black line) the addition of a fixed low concentration of PfRH5-immunized rabbit IgG (0.156 mg/mL) which, when used alone, gives approximately 20% GIA (dashed black line). Predicted additive effects were calculated according to Bliss independence (see <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002991#s4" target="_blank">Materials and Methods</a>) and illustrated as the red line on each graph. Data points represent the mean of triplicates from two independent experiments. Bars indicate SEM for all six replicates over two experiments. Asterisks indicate that the predicted and observed values differed significantly (*<i>P</i><0.05; ** <i>P</i><0.01; 2-way ANOVA with Bonferroni post-hoc testing).</p

Antigen-specific EC₅₀ estimation for anti-PfRH5 and anti-PfAMA1 IgG against short-term-adapted Cambodian parasite isolates.

<p>Dose-response curves were fitted to all GIA versus antigen-specific antibody concentration data for <b>A</b>) CP803, <b>B</b>) CP806, <b>C</b>) CP830, <b>D</b>) CP845 and <b>E</b>) CP887 (multiple IgG dilutions for each of five rabbits for PfRH5 and each of four rabbits for PfAMA1). Dashed vertical lines indicate the fitted EC₅₀ value for anti-PfRH5 IgG (red) or anti-PfAMA1 (black) IgG for that isolate. Each value is the mean of three wells in a single experiment. Red indicates anti-PfRH5 samples; black indicates anti-PfAMA1 samples.</p

Associations between IgG antibody avidity and total IgG ELISA titer.

<p>Associations are reported between anti-MSP1₁₉ ETSR allele or anti-AMA1 3D7 allele total IgG ELISA titer readouts (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0107903#pone-0107903-g001" target="_blank">Figure 1B, D</a>) and the corresponding IgG avidity measurement by NaSCN-displacement ELISA (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0107903#pone-0107903-g003" target="_blank">Figure 3E, F</a>). Groups were assessed according to vaccination and/or parasite exposure status as outlined in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0107903#pone-0107903-g003" target="_blank">Figure 3E, F</a>. In all cases, Spearman’s rank correlation coefficient and <i>P</i> value are shown. n.d. = not done (too few positive responders). *Data from vaccinees receiving only a single vaccine (i.e. MSP1-only or AMA1-only) were used for this analysis.</p><p>Associations between IgG antibody avidity and total IgG ELISA titer.</p

Assessment of antibody isotype profiles following vaccination, CHMI and natural exposure.

<p>Isotype profiles of serum antibody responses were assessed by ELISA. (A) Individual and median anti-MSP119 serum antibody isotype responses are shown for MSP1-only vaccinees at the peak after the MVA MSP1 boost (“Vaccine”, <i>n</i> = 12) and at dC+35 following CHMI (“Vaccine+CHMI”, <i>n</i> = 11) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0107903#pone.0107903-Sheehy3" target="_blank">[21]</a>; at dC+35 for 18 infectivity control volunteers from three separate CHMI studies <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0107903#pone.0107903-Sheehy3" target="_blank">[21]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0107903#pone.0107903-Ewer1" target="_blank">[22]</a>; and from 20 naturally-exposed immune adults from Kilifi, Kenya. (B) Individual and median anti-AMA1 serum antibody isotype responses are shown for AMA1-only vaccinees at the peak after the MVA AMA1 boost (<i>n</i> = 9) and at dC+35 following CHMI (<i>n</i> = 9) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0107903#pone.0107903-Sheehy3" target="_blank">[21]</a>; and for infectivity control volunteers and naturally-exposed immune adults from Kilifi, Kenya as in panel A.</p