Figure 9.

Antigen-specific responses in TLN lymphocyte recall assays. Cytokine concentrations in supernatants of TLN cells that were harvested at day 20 pi and then stimulated with antigen were measured with cytometric bead arrays. Nb Ag, a crude Nb adult lysate, and recombinant Pcc clone AS merozoite surface protein, MSP-1₁₉, were used as antigens in vitro. Although all cytokines shown in Figure 8 were measured, only IL-13 in response to Nb Ag (A), IL-5 in response to Nb Ag (B), IL-6 in response to MSP-1₁₉ (C), and TNF-α in response to MSP-1₁₉ (D) were above levels of spontaneous secretion. These figures thus depict antigen-specific cytokine (in ng/ml above background). Statistically significant differences among groups included increased NbAg-specific IL-13 in all Nb mice (P < 0.0001), increased Nb Ag-specific IL-5 in co-infected (Nb+Pcc) mice compared to both Nb (P = 0.0025) and Pcc mice (P < 0.0001), and increased MSP-1₁₉-specific IL-6 in Nb+Pcc compared to both Nb (P = 0.0163) and Pcc mice (P = 0.0112). Bars indicate mean ± SEM for 4-8 mice per group. The symbol ¶ indicates significance of the difference between co-infected and Nb mice, while § indicates significance of the difference between co-infected and Pcc mice (P values included above and in Results text).