Shift in epitope dominance of IgM and IgG responses to Plasmodium falciparum MSP1 block 4

<p>Abstract</p> <p>Background</p> <p><it>Plasmodium falciparum </it>merozoite surface protein-1 (MSP1) has been extensively studied as a blood-stage malaria vaccine candidate, with most work focused on the conserved 19 kDa and semi-conserved 42 kDa C-terminal regions (blocks 16-17) and the hypervariable N-terminal repeat region (block 2). However, recent genotyping studies suggest that additional regions of MSP1 may be under selective pressure, including a locus of intragenic recombination designated as block 4 within the 3' region of the gene.</p> <p>Methods</p> <p>The current study examined the antibody response to the two parental and two recombinant forms of block 4 and to blocks 16-17 (3D7) in study populations from Colombia, Papua New Guinea and Cameroon that differ in malaria transmission intensity and ethnic composition.</p> <p>Results</p> <p>IgM and IgG antibodies were detected against parental and recombinant MSP1 block 4 peptides in all three populations. Overall, 32-44% of the individuals produced IgM to one or more of the peptides, with most individuals having IgM antibodies reactive with both parental and recombinant forms. In contrast, IgG seropositivity to block 4 varied among populations (range 15-65%), with the majority of antibodies showing specificity for one or a pair of block 4 peptides. The IgG response to block 4 was significantly lower than that to blocks 16-17, indicating block 4 is subdominant. Antibodies to block 4 and blocks 16-17 displayed distinct IgG subclass biases, with block 4 responses biased toward IgG3 and blocks 16-17 toward IgG1. These patterns of responsiveness were consistently observed in the three study populations.</p> <p>Conclusions</p> <p>Production of antibodies specific for each parental and recombinant MSP1 block 4 allele in different populations exposed to <it>P. falciparum </it>is consistent with balancing selection of the MSP1 block 4 region by the immune response of individuals in areas of both low and high malaria transmission. MSP1 block 4 determinants may be important in isolate-specific immunity to <it>P. falciparum</it>.</p

Foot-and-mouth disease:overview of motives of disease spread and efficacy of available vaccines

Control and prevention of foot and mouth disease (FMD) by vaccination remains unsatisfactory in endemic countries. Indeed, consistent and new FMD epidemics in previously disease-free countries have precipitated the need for a worldwide control strategy. Outbreaks in vaccinated animals require that a new and safe vaccine be developed against foot and mouth virus (FMDV). FMDV can be eradicated worldwide based on previous scientific information about its spread using existing and modern control strategies