Detectability of cytokine and chemokine using ELISA, following sample-inactivation using Triton X-100 or heat

Figures

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  Fig. 1. Detection of IL-1α in heat- and Triton X-100- treated versus untreated control samples from (a) ETTA, (b) NP Swab, and (c) Plasma. Paired aliquots of the same sample (connected with a line) were inactivated by exposure to 60 °C for 1 h (▲), or Triton X-100 (0.05%, ♦), or left untreated on ice (○). Some samples were unpaired due to unavailability of sample to be tested in all three conditions. One sample in 1c is missing the Triton X-100 treated aliquot. The levels of IL-1α detected in these samples were assayed and compared using paired t-test: ‘*’ denotes p < 0.05, ‘**’ denotes p < 0.005.

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  Fig. 2. The magnitude of effects of heat and Triton X-100 on the detection of IL-1α measured in percentage changes from the untreated samples. Paired aliquots of the same sample (connected with a line) were inactivated by exposure to 60 °C for 1 h (▲), or Triton X-100 (0.05%, ♦), or left untreated on ice. Some samples were unpaired due to unavailability of sample to be tested in all three conditions. The magnitude of effects on IL-1α detection in percentage was tested against a hypothetical value ‘0’ (dashed line on the graph) using “Wilcoxon Signed Rank Test”. The dashed line represents ‘0%’ deviation from the detected level of cytokine/chemokine in the untreated samples and is calculated as [(Streated−Suntreated Ctrl)/ Suntreated Ctrl × 100%].The p-values were shown near x-axis. The difference in the magnitude effects between the two inactivation-methods was tested using "Wilcoxon matched-pairs signed rank test". ‘*’p < 0.05, ‘**’p < 0.005.

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  Fig. 3. Summary of the effects of heat and Triton X-100 on the detectability of cytokine/chemokine, expressed as percent change, in ETTA, NP Swab, and plasma samples. Each dot represents a cytokine or chemokine in a clinical sample treated by either heat 60 °C for 60 min or 0.5% Triton X-100. Dot colour-scale is based on median % value. Using untreated sample as reference, decrease or increase in % of cytokine/chemokine detected in the treated samples were shown in blue or red color, respectively. Grey color depicts ‘no difference’ from the untreated reference sample. Exact percent change values can be found in Table S2. The size of the dot represents log10 p-values. The larger the dot in diameter, the lower the p-values (Pratt two-tailed Wilcoxon Signed Rank Test).