Antibodies to liver stage associated with malaria ...( Duffy Director of the Malaria Antigen ...)

Duffy is also an author on the study. "When we repeated the study with a smaller group the following year we saw a similar trend."

Kurtis and Duffy are quick to point out that these results do not prove that high antibody levels to LSA-1 are the cause of disease resistance, only that they are correlated with it.

"We recognize this as a very useful marker for predicting who might have resistance," says Duffy. "The key question is, what is the immune response that is mediating protection? It seems unlikely that the antibody response to LSA-1 alone is enough to prevent infection."

"Other immune responses against LSA-1 are associated with infection as well. In our minds, targeting a vaccine against LSA might be an important component of a malaria vaccine strategy," says Kurtis.

One finding that caught the researchers' attention was that the antibodies that were associated with protection were not those that are typically associated with long-term immunity, the IgG antibodies, but instead were those most commonly seen during and just after an acute infection, the short-term or IgM antibodies.

"In future research we need to seek to better understand how the cells that make IgG and IgM, called B-cells, are stimulated and modulated during malaria infection," says Duffy. "Why don't people mount long-term responses to malaria antigens? Once we figure that out we can translate that information into developing new long-lasting vaccines and therapies."

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Contact: Jim Sliwa
jsliwa@asmusa.org
202-942-9297
American Society for Microbiology
12-Nov-2001