FIG. 2.

Lymph node T-cell proliferative responses in BALB/c and C57BL/6 mice immunized with PfLSA-1-based synthetic peptides. All mice were immunized with 60 to 70 μg of peptide in CFA, and 10 to 12 days later cells from the draining lymph nodes were cultured for 100 h with various concentrations of homologous peptides. Concanavalin A (5 μg/ml) was used as a positive control. All values are means of quadruplicate determinations with standard deviations not more than 20% of the means. The results are expressed as SIs, defined as counts per minute in stimulated cultures divided by counts per minute in unstimulated cultures. An SI value of more than 2.0 was scored as positive result. Background counts per minute ranged from 235 to 5,560 for BALB/c mice and from 160 to 6,446 for C57BL/6 mice in all cases. The results shown are from three experiments performed separately, and results are expressed as maximum SI obtained at a given peptide concentration.