When the post-infection fold increase (absorbance ratio: day 42/day 0) was plotted against the CD4+ cell counts “Fig 5” to determine if there was a relationship between post-infection increase in anti-peptide IgG and CD4+ cells counts (results not shown), Spearman’s test revealed no significant relationship between the CD4+ cell counts and the memory increase of antibody against peptides MSP-3, GLURP and HRPII. This evidence concerns the gene CD4 and infection.