F(ab)(2)'-immunoglobulin (
Ig) fragments induced by site-directed designed immunogens are emerging as novel tools of potential utility in the treatment of clinical episodes of transmissible diseases such as
malaria. Immunogens based on reduced
amide pseudopeptides based on site-directed molecular modifications represent structural probes that could be considered as novel
vaccine candidates, as we have previously demonstrated. We have obtained F(ab)(2)'-Ig rabbit
antibodies induced against the N-terminal sequence of the native
Merozoite Surface Protein-1 (MSP-1) of Plasmodium falciparum and a set of five MSP-1-derived reduced
amide pseudopeptides. Pseudopeptides were designed for inducing functional neutralizing mono-specific polyclonal
antibodies with potential applications in the control of
malaria. Following a classical
enzyme immunoglobulin fractionation, F(ab)(2)'-Ig fragments were tested for their ability to suppress blood-stage
parasitemia by passive immunization in
malaria-infected mice. Some of these fragments proved totally effective in suppressing a lethal blood-stage challenge
infection and others reduced malarial
parasitemia. These data suggest that protection against Plasmodium yoelii
malaria following passive transfer of structurally well-defined β-strand F(ab)(2)'-Ig fragments can be associated with specific
immunoglobulins induced by site-directed designed
MSP-1 reduced
amide pseudopeptides.