CD4+ T cell responses to an invariant CSP epitope present in RTS,S have been associated with natural protection against infection [15], and recent genetic analysis of csp sequences encoding theTh2R and Th3R epitopes in 238 isolates from Thailand does not support the notion that diversity in these epitopes is generated in response to selection by sequence-specific human immunity in that population [16]. This evidence concerns the gene DNAJC5 and infection.