Leishmania mexicana cysteine protease, CPB2.8, induces potent Th2 responses.

2003 APR 2 - (NewsRx.com & NewsRx.net) -- The Leishmania mexicana cysteine protease, CPB2.8, induced a potent Th2 response in mice.

"We have previously identified that Leishmania mexicana cysteine proteases (CPs) are virulence factors. We have now produced a recombinant L. mexicana CP, CPB2.8, which has similar enzymatic activity to native enzyme," researchers in Scotland report.

"Inoculation of CPB2.8 (less than or equal to5 microgram) into the footpads of BALB/c mice not only up-regulated mRNA transcripts for IL-4 and IL-4 production in the draining popliteal lymph nodes, but also polarized splenocyte anti-CD3 stimulated responses toward a Th2 bias as measured by increased IL-5 production compared with controls," stated Kevin G. J. Pollock and colleagues at the Universities of Strathclyde and Glasgow. "In agreement with promoting a Th2 response, CPB2.8 also induced strong specific IgE responses in treated mice as well as increasing whole IgE levels. Inhibition of the enzyme activity of CPB2.8 by treatment with E-64 ablated the enzyme's ability to induce IgE."

"Significantly, infection of mice with CPB-deficient parasites failed to stimulate production of IgE, unlike infection with wild-type parasites," the investigators reported. "Furthermore, enzymatically active (

The researchers concluded, "Vaccination with CPB2.8 enhanced L. mexicana lesion growth compared with control animals. Nevertheless, ...